Sansui QRS5500 quadrophonic receiver

This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

 

I hope you mean a QRX, not QRS. They got it at hifiengine, it shows a fuse for the dial lamps, F 01, 5 amps. It also feeds a rectifier for about an 8 volt source that feeds the stereo light, also off the fuse. While at this age those lamps may have blown one at a time by now, you would have noticed it.

the cap in the protection, the failure mode is weird. They are usually 10 volts and sometimes go right across B to E of a transistor so they never charge more than like a half a volt. they get leakier and leakier over time. They are usually fed by a high value resistor, like 100K or more. I didn't look at that part of the circuit but since it is fine, fukit.

Not a badly designed piece. Full comp outputs, current source instead of a bootstrap, DC coupled. Theoretical peak RMS short tem power is 76.5 WPC. The rating is 30, so splitting the difference I would say you got about 1.5 dB or so dynamic headroom. It is probably over 3 dB for a couple milliseconds, but in real life not so much.

Tuner is pretty conventional, uses ceramic filters but still a standard ratio detector. No pilot cancel, but all that doesn't mean it doesn't sound good.

Tone controls OK, filters only 6 dB, don't use the filters. he variomatrix looks like a good thing, like Marantz varimatrix I would guess. You have control over the L+R attenuatoin in the rear.

I don't see amp strapping in it though, or pre out/main in.

Enough commentary, if it is QRX the manual is at hifiengine.com. It is probably ready for the FM to be tweaked, but it might not be so bad. Other than fixing the lights, if all the channels sound good I don't recommend anything. You could go in with an ESR meter and replace caps if you feel like it. Just never short the speaker wires because it has no current limiting at all.

 

[David Farber]

jurb6006@gmail.com wrote:

I hope you mean a QRX, not QRS. They got it at hifiengine, it shows a
fuse for the dial lamps, F 01, 5 amps. It also feeds a rectifier for
about an 8 volt source that feeds the stereo light, also off the
fuse. While at this age those lamps may have blown one at a time by
now, you would have noticed it.

the cap in the protection, the failure mode is weird. They are
usually 10 volts and sometimes go right across B to E of a transistor
so they never charge more than like a half a volt. they get leakier
and leakier over time. They are usually fed by a high value resistor,
like 100K or more. I didn't look at that part of the circuit but
since it is fine, fukit.

Not a badly designed piece. Full comp outputs, current source instead
of a bootstrap, DC coupled. Theoretical peak RMS short tem power is
76.5 WPC. The rating is 30, so splitting the difference I would say
you got about 1.5 dB or so dynamic headroom. It is probably over 3 dB
for a couple milliseconds, but in real life not so much.

Tuner is pretty conventional, uses ceramic filters but still a
standard ratio detector. No pilot cancel, but all that doesn't mean
it doesn't sound good.

Tone controls OK, filters only 6 dB, don't use the filters. he
variomatrix looks like a good thing, like Marantz varimatrix I would
guess. You have control over the L+R attenuatoin in the rear.

I don't see amp strapping in it though, or pre out/main in.

Enough commentary, if it is QRX the manual is at hifiengine.com. It
is probably ready for the FM to be tweaked, but it might not be so
bad. Other than fixing the lights, if all the channels sound good I
don't recommend anything. You could go in with an ESR meter and
replace caps if you feel like it. Just never short the speaker wires
because it has no current limiting at all.

Just a hunch here but I remember there were many Sansui models manufactured
in that era that had faulty rotary function selector switches. The result
was that the panel lights would flicker or go out completely. No amount of
switch cleaning would restore them to good health. If you wiggle the
function selector switch, do the lights flicker or does the meter function
momentarily?

--
David Farber
Los Osos, CA

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

I think that I know what the problem is. I first sprayed the main
selector switch with a silicon based cleaner that contains a mild
lubricant, figuring that one of the phenolic wafer sections in the
..switch that was switching the power for the lamps perhaps was dirty.
This stuff evaporates quickly and it didn't solve the problem. After
more fruitless probing, in a last ditch effort I hit all the segments
of the switch with No Ox. This stuff is like "Blue Stuff" but a bit
more oily. I worked the switch to distribute the material and then
powered the unit on. No Ox works wonders with controls and switches
but it is some what messy.To my utter dismay I noticed smoke coming
off part of the selector switch. (This was probably from the sector
that is switching the high current lamp power. I now have to pull the
front panel and hope that I then will be able to get a better eyeball
of the selector switch. If the section is burned though I don't know
what I could possibly do though. A selector switch problem....... My
worst fear becomes a reality. Is today the thirteeth by any chance?
Lenny

On 6/22/18, Ardell Faul ardellfaul@gmail.com [tv-repair]
- Show quoted text -
Quick Reply
To: tv-repair@yahoogroups.com

 

Jump out the switch and see if it blows the 5 amp fuse.

I think 5 amps is a bit much for that type of switch.

 

[Chuck]

On Fri, 22 Jun 2018 13:35:43 -0700 (PDT), captainvideo462009@gmail.com
wrote:

This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Lenny,
See my answer on the Yahoo tv-repair group. Chuck

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:

This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

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I had actually thought of that. It wouldn't be a problem if the lamps
were on for each mode. I just wish that I could see the burned section
of the switch but it's an impossible jungle of wires.

Two weeks ago before I knew about the lighting problem I picked up a
5500 to use for parts, because my quad section has never worked and I
have been thinking that it would be nice to swap a couple o boards and
see what happens. So I have a switch however there is no way I'm
going to tackle replacing that switch.

I thought o something else. Back in the late 60's and early to mid
seventies when VHF TV tuners were built with multisection switches I
used to run across a fair number of them that just wouldn't respond to
a good cleaning with a silicon based tuner cleaner. Then they came
out with "Blue Stuff". As long as you didn't spray it on the
neutralizing capacitors it was a miracle of bringing back intermittent
tuners to life once again. I
So I thought I might try degreasing the switch first and then give it
a good cleaning with Blue stuff. and then see what happens. Probably
nothing will come of it but it doesn't hurt to try I guess. Lenny

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Hey guys I really need some more help with this one. It's on the bench and even though I'm working on it my wife is flipping out over the entertainment center all torn apart in the living room. But that's a woman for you, can't appreciate the beauty of a repaired 1974 receiver...

Anyway in looking at the schematic I can see that there is a 6 volt winding referenced to ground. The blue 6 volt transformer wire goes through a 5 amp fuse the output of which directly feeds AC to a bunch of lamps in parallel. The output of the fuse also feeds a rectifier and filter which then feeds DC to some other lamps through some other switches. I just can't make any sense out of it.

For one thing although I can see a multi pole switch feeding individual lamps and I'm assuming they are indicators I can't tell for sure which lamps are for which function, (panel lights or indicators) and so I'm not certain where to jump because I can't tell which lamps would need to powered by AC or DC. Most of the ones that seem to be indicators such as phono, tape, etc.. seem to light now and it would be nice to retain that after jumping out whatever I need to to restore the other lights.

Another weird thing which is also troubling is that every once in awhile the signal meter seems to illuminate although it doesn't seem like it's fully bright and there is never any signal level response on it. I never had trouble with that either. Can one of you guys please help me with determining where to "jump" the switch and get all the lamps working? Then I'll have to figure out this signal meter problem. Thanks, Lenny

 

[Chuck]

On Sun, 24 Jun 2018 10:24:54 -0700 (PDT), captainvideo462009@gmail.com
wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Hey guys I really need some more help with this one. It's on the bench and even though I'm working on it my wife is flipping out over the entertainment center all torn apart in the living room. But that's a woman for you, can't appreciate the beauty of a repaired 1974 receiver...

Anyway in looking at the schematic I can see that there is a 6 volt winding referenced to ground. The blue 6 volt transformer wire goes through a 5 amp fuse the output of which directly feeds AC to a bunch of lamps in parallel. The output of the fuse also feeds a rectifier and filter which then feeds DC to some other lamps through some other switches. I just can't make any sense out of it.

For one thing although I can see a multi pole switch feeding individual lamps and I'm assuming they are indicators I can't tell for sure which lamps are for which function, (panel lights or indicators) and so I'm not certain where to jump because I can't tell which lamps would need to powered by AC or DC. Most of the ones that seem to be indicators such as phono, tape, etc. seem to light now and it would be nice to retain that after jumping out whatever I need to to restore the other lights.

Another weird thing which is also troubling is that every once in awhile the signal meter seems to illuminate although it doesn't seem like it's fully bright and there is never any signal level response on it. I never had trouble with that either. Can one of you guys please help me with determining where to "jump" the switch and get all the lamps working? Then I'll have to figure out this signal meter problem. Thanks, Lenny

Lenny,
Jumper Pin 02 on F-1483 board to the end of R0118 that goes to PL01.
Jumper the B+ end of PL707 to B+ end of PL713. Jumper B+ end of PL 701
to B+ end of PL704. This should allow all lights except for mode ones
to light. I'd put a 100 watt light bulb in series with the AC in just
in case I screwed up. As a retiree, my mind isn't what it once was.
Good luck.

 

[John-Del]

On Sunday, June 24, 2018 at 5:09:26 PM UTC-4, Chuck wrote:

On Sun, 24 Jun 2018 10:24:54 -0700 (PDT), captainvideo462009@gmail.com
wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Hey guys I really need some more help with this one. It's on the bench and even though I'm working on it my wife is flipping out over the entertainment center all torn apart in the living room. But that's a woman for you, can't appreciate the beauty of a repaired 1974 receiver...

Anyway in looking at the schematic I can see that there is a 6 volt winding referenced to ground. The blue 6 volt transformer wire goes through a 5 amp fuse the output of which directly feeds AC to a bunch of lamps in parallel. The output of the fuse also feeds a rectifier and filter which then feeds DC to some other lamps through some other switches. I just can't make any sense out of it.

For one thing although I can see a multi pole switch feeding individual lamps and I'm assuming they are indicators I can't tell for sure which lamps are for which function, (panel lights or indicators) and so I'm not certain where to jump because I can't tell which lamps would need to powered by AC or DC. Most of the ones that seem to be indicators such as phono, tape, etc. seem to light now and it would be nice to retain that after jumping out whatever I need to to restore the other lights.

Another weird thing which is also troubling is that every once in awhile the signal meter seems to illuminate although it doesn't seem like it's fully bright and there is never any signal level response on it. I never had trouble with that either. Can one of you guys please help me with determining where to "jump" the switch and get all the lamps working? Then I'll have to figure out this signal meter problem. Thanks, Lenny
Lenny,
Jumper Pin 02 on F-1483 board to the end of R0118 that goes to PL01.
Jumper the B+ end of PL707 to B+ end of PL713. Jumper B+ end of PL 701
to B+ end of PL704. This should allow all lights except for mode ones
to light. I'd put a 100 watt light bulb in series with the AC in just
in case I screwed up. As a retiree, my mind isn't what it once was.
Good luck.

Hmmmm... I would probably drill holes in the backs of all the gauges and just globally light up the entire inside of the receiver...

Lenny, I've got about a dozen receivers abandoned from repairs over the years and some of them are quite vintage, although none are quad to my recollection. If you want one, stop by next time you're coming through CT and you can pick out what you want.

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck

First, thank you very much for the power supply jumper information. I hope that I will not have to use it but it is comforting to have it. The reason I say this is because in the interim I tried my Blue Stuff treatment. I sprayed the switch sections quite liberally and I really worked the switch through all of it's positions.

What I had previously written about the effect that Blue had on the intermittent phenoclic switches in the old tuners was not an overstatement. My display lamps are all on now and there is no smoke. I guess that I would say that I'm "cautiously optimistic" that I may actually have restored these tarnished contacts before they actually had a chance to burn.

I've turned the receiver on a few times now since the Blue Stuff treatment and and the display has come on strong without flickering each time. I guess we'll see.

Now I have to address the other problem with the non functioning signal meter. As I had said it always worked before and never caused a problem. But now it just lights up and does not indicate signal.

I really don't see how but could this be some crazy kind of coincidence, or perhaps something associated with the lighting system problem?

The tuner section of the schematic, F-1479-2A shows two meters and one small 6V 100ma lamp. Please correct me if I'm wrong but M705 looks like it could be the signal level meter and M706 looks like it is connected to the discriminator output for station centering. Then there is that small 6 volt 100ma. lamp which is connected off pin 12 of the board. Could that be the stereo lamp? To troubleshoot the signal level problem would M705 simply get a DC output off that HA1120 chip and through the transistor proportional to signal strength? Thanks for any further help. It is very much appreciated.
Lenny

 

>"non functioning signal meter"

Also goes through the switch, usually.

 

[John-Del]

On Wednesday, June 27, 2018 at 3:30:53 AM UTC-4, captainvi...@gmail.com wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck

First, thank you very much for the power supply jumper information. I hope that I will not have to use it but it is comforting to have it. The reason I say this is because in the interim I tried my Blue Stuff treatment. I sprayed the switch sections quite liberally and I really worked the switch through all of it's positions.

What I had previously written about the effect that Blue had on the intermittent phenoclic switches in the old tuners was not an overstatement. My display lamps are all on now and there is no smoke. I guess that I would say that I'm "cautiously optimistic" that I may actually have restored these tarnished contacts before they actually had a chance to burn.

I've turned the receiver on a few times now since the Blue Stuff treatment and and the display has come on strong without flickering each time. I guess we'll see.

Now I have to address the other problem with the non functioning signal meter. As I had said it always worked before and never caused a problem. But now it just lights up and does not indicate signal.

I really don't see how but could this be some crazy kind of coincidence, or perhaps something associated with the lighting system problem?

The tuner section of the schematic, F-1479-2A shows two meters and one small 6V 100ma lamp. Please correct me if I'm wrong but M705 looks like it could be the signal level meter and M706 looks like it is connected to the discriminator output for station centering. Then there is that small 6 volt 100ma. lamp which is connected off pin 12 of the board. Could that be the stereo lamp? To troubleshoot the signal level problem would M705 simply get a DC output off that HA1120 chip and through the transistor proportional to signal strength? Thanks for any further help. It is very much appreciated.
Lenny

IIRC, the Blue Stuff product contained an actual abrasive along with the blue schmutz carrier. If the abrasive scoured the contacts into working, I think I'd follow it up with a non residue cleaner to get the blue carrier off. I remember the blue carrier thickening into a stiff almost glue like consistency over time.

 

[Chuck]

On Wed, 27 Jun 2018 00:30:50 -0700 (PDT), captainvideo462009@gmail.com
wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck

First, thank you very much for the power supply jumper information. I hope that I will not have to use it but it is comforting to have it. The reason I say this is because in the interim I tried my Blue Stuff treatment. I sprayed the switch sections quite liberally and I really worked the switch through all of it's positions.

What I had previously written about the effect that Blue had on the intermittent phenoclic switches in the old tuners was not an overstatement. My display lamps are all on now and there is no smoke. I guess that I would say that I'm "cautiously optimistic" that I may actually have restored these tarnished contacts before they actually had a chance to burn.

I've turned the receiver on a few times now since the Blue Stuff treatment and and the display has come on strong without flickering each time. I guess we'll see.

Now I have to address the other problem with the non functioning signal meter. As I had said it always worked before and never caused a problem. But now it just lights up and does not indicate signal.

I really don't see how but could this be some crazy kind of coincidence, or perhaps something associated with the lighting system problem?

The tuner section of the schematic, F-1479-2A shows two meters and one small 6V 100ma lamp. Please correct me if I'm wrong but M705 looks like it could be the signal level meter and M706 looks like it is connected to the discriminator output for station centering. Then there is that small 6 volt 100ma. lamp which is connected off pin 12 of the board. Could that be the stereo lamp? To troubleshoot the signal level problem would M705 simply get a DC output off that HA1120 chip and through the transistor proportional to signal strength? Thanks for any further help. It is very much appreciated.
Lenny
Lenny,

Does the meter work on AM? If it does then either there is a bad
connection from VR2 on the F1479 board to the meter or, more commonly,
the potentiometer is faulty. If it doesn't work on AM, either the
meter coil is open or the wire to ground or the plus wire from the
circuit board is open or C 98 is shorted. Hope one of these hunches is
correct. Chuck

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck
I put a remote near the antenna and it does respond to AM. I did see it respond to FM at one point too. But then it didn't seem to after awhile. The thing is I can't find VR2 that you mentioned. Which meter is the signal meter? Lenny

 

[Chuck]

On Wed, 27 Jun 2018 15:43:58 -0700 (PDT), captainvideo462009@gmail.com
wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck
I put a remote near the antenna and it does respond to AM. I did see it respond to FM at one point too. But then it didn't seem to after awhile. The thing is I can't find VR2 that you mentioned. Which meter is the signal meter? Lenny

Lenny,
M705. I wonder if the the meter movement is sticky?

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck
I'm embarrassed to say that I think I know what happened. The RF
section on this receiver is pretty hot and so for servicing it on my
bench I didn't bother connecting the old outside VHF/FM antenna that
is now used just for FM, throughout our house. I was getting what I
thought was a decent signal in my basement with just a short piece of
wire connected to the high side of the 300 ohm terminals. Apparently
in spite of the fact that the FM stations I was tuning in sounded OK
there must be a signal threshold that must be met before the signal
meter will move. With the unit connected to the outside antenna the
signal; meter is now working fine. I don't think that there was ever
a problem with it.
It was more aptly due to "operator head space"

So now I'm at the final stage of this repair. I have owned this
receiver for over thirty years now. I originally bought it from the
junk man at our town dump who was going to strip it, for 5.00 It has
been a great receiver for all this time,however the 4 channel
circuitry never seemed to work properly on it. I worked on it, John
Del, also a contributor to this thread worked on it as well, but we
never seemed to be able to resolve it. So for that time I have lived
with it.

A few weeks ago I was browsing Craig's List and found a guy about 30
miles from my house who had one of these for sale. I went out, and
looked at it and thought it might need a discriminator alignment, and
I picked it up for parts. So today, first I swapped out the 2048
board. I now have output on all 4 channel positions except the first
and last, which seems like it should be. I have 4 speakers connected
to speaker A front and back terminals. It seems to sound "OK:" but I
can hear a very slight "popping" way down in the mud in the rear
speakers.

So I was going to swap out the 2047 board, however in spite of the
fact that it would fit in the same slot as my original, the board from
the donor receiver is totally different. For one thing there are 7
potentiometers on the donor board and only three on my original board.
There are also two 8 pin chips on the original board but it seems to
be all discrete components on the donor board. So for boards that fit
into the same positions in the chassis are these boards forward and
backward compatible? After all this I would hate to make a swap and
because it was incompatible wind up destroying something.
Lenny

 

[Chuck]

On Thu, 28 Jun 2018 14:11:48 -0700 (PDT), captainvideo462009@gmail.com
wrote:

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in
parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck
I'm embarrassed to say that I think I know what happened. The RF
section on this receiver is pretty hot and so for servicing it on my
bench I didn't bother connecting the old outside VHF/FM antenna that
is now used just for FM, throughout our house. I was getting what I
thought was a decent signal in my basement with just a short piece of
wire connected to the high side of the 300 ohm terminals. Apparently
in spite of the fact that the FM stations I was tuning in sounded OK
there must be a signal threshold that must be met before the signal
meter will move. With the unit connected to the outside antenna the
signal; meter is now working fine. I don't think that there was ever
a problem with it.
It was more aptly due to "operator head space"

So now I'm at the final stage of this repair. I have owned this
receiver for over thirty years now. I originally bought it from the
junk man at our town dump who was going to strip it, for 5.00 It has
been a great receiver for all this time,however the 4 channel
circuitry never seemed to work properly on it. I worked on it, John
Del, also a contributor to this thread worked on it as well, but we
never seemed to be able to resolve it. So for that time I have lived
with it.

A few weeks ago I was browsing Craig's List and found a guy about 30
miles from my house who had one of these for sale. I went out, and
looked at it and thought it might need a discriminator alignment, and
I picked it up for parts. So today, first I swapped out the 2048
board. I now have output on all 4 channel positions except the first
and last, which seems like it should be. I have 4 speakers connected
to speaker A front and back terminals. It seems to sound "OK:" but I
can hear a very slight "popping" way down in the mud in the rear
speakers.

So I was going to swap out the 2047 board, however in spite of the
fact that it would fit in the same slot as my original, the board from
the donor receiver is totally different. For one thing there are 7
potentiometers on the donor board and only three on my original board.
There are also two 8 pin chips on the original board but it seems to
be all discrete components on the donor board. So for boards that fit
into the same positions in the chassis are these boards forward and
backward compatible? After all this I would hate to make a swap and
because it was incompatible wind up destroying something.
Lenny

Lenny,
The board compatibility question I can't answer. Back in the day we
never switched out whole boards on Sansuis. Always troubleshot to the
component level. Sorry. Chuck

 

On Friday, June 22, 2018 at 4:35:46 PM UTC-4, captainvi...@gmail.com wrote:
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

Chuck
I took a leap of faith assuming that if the second 4 channel board fit mechanically it would work electronically. And to my great luck and surprise it did! I'm not sure if I now have two earlier or later versions of the quad boards in there now but they were apparently compatible. And the retrofit worked quite well too. The very slight "popping" noise that I had previously heard out of the rear speakers was gone, the dead rear channel is restored, and in fact the sound was clean through all the speakers. I have never heard "4 channel" out of this unit so this is going to be thrilling uncharted waters.

Now I do realize that no one broadcasts 4 channel analog any more and I also know that sources to reproduce it including any records, or tapes, etc are probably few and far between anyway. But I was wondering if you might have any information on that?

The guy that I bought the organ donor from included a large plasticized sheet with it showing all possible hookups. It also had brief explanations of all controls and their positions and there seems to be a couple of "synthesized" positions that according to this hookup sheet can apparently simulate 4 channel sound. I think that those look like "hall" and "surround". I do feel like When listening in some of these positions, perhaps I may be imagining it but the sound does seem to take on a whole new spaciousness to it..

I recall hearing years ago when I first contacted Sansui for a service manual that the 5500 sold for over 900.00 back in it's hey day. In 1974 I was living in a small apartment over a restaurant with my cat. I wouldn't have been able to afford the carton to pack this in.

So now after all these years I that finally own that has the capability to be used in ways that were not available to me before I don't really know what to expect from it. And so I was wondering if you might be willing to comment on that experience and maybe 4 channel analog in general. Thanks again.. Lenny

 

Wanna buy a Marantz CD-400B CD-4 disk demodulator ?
Cosmetically fair, and I checked that is works by injecting a carrier from a generator with a VCG function and modulated it. It was loosely coupled capacitively to the input, a wire near the jacks with the cover off. The signal came out of the outputs. I have a picture of that setup working.

Of course I have no CD-4 records, and no compatible cartridge, but I know it works.