Toshiba TV29C90 problem; Image fades to black...

[Mark D. Zacharias]

And while you're at it, lose the "top-posting" nonsense. No one elected you
sheriff of this one-horse town.

Mark Z.


Simoc wrote:

Hi!

I got Technics 323 tuner amp, which is lacking a volume pot. It has
balance adjustment on the same knob, too. The knob came with it, it
has a "head" and "sleeve" which both have the same radius, and have no
space between them.

So might the balance adjustment be done so that the "head" just
adjusts one channel and the sleeve the other, and thus their ratio
could be adjusted, and when the volume is adjusted, both of them (ie.
the entire knob) are turned same amount?

What might be the name of the pot of such kind (a stereo pot having
the both channels separately adjustable?)

Then there is one more problem. There is a 5-wire ribbon cable for
connection of the pot...what might be the pinout? Or if anyone doesn't
know, how could I analyze it with a scope maybe? It just cannot be
easily done by analyzing the circuit, since the mainboard is very
complex and has a lot of stuff above it, and the device hasn't a
detachable bottom, so disassembling for analyzing the circuit would be
quite an infernal job...:

 

[Homer J Simpson]

<lsmith2660@aol.com> wrote in message
news:1164294597.995724.139640@j44g2000cwa.googlegroups.com...

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

Gas, electric, heat pump?

 

[Jumpster Jiver]

lsmith2660@aol.com wrote:

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

When I opened up where the switch is located it made a spark and then
nothing else happend, did the switch burn out?

Please help!

Thank You.

Most AC elctrical switches will spark when turned off and sometimes a

spark can be seen when turning it on.
If it sparks when switched it is probably OK and there's something else
causing it to not work.
If you don't know how to safely troubleshoot your system or don't know
where to look next, you should call a repair service.
Whether it's electric or gas, oil or any other system, you can be
injured or damage or destroy your home if the system is incorrectly
serviced.
As always, if you smell gas leave the house immediately without
switching lights on or off and call the fire department from a different
location.

 

[CJT]

lsmith2660@aol.com wrote:

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

When I opened up where the switch is located it made a spark and then
nothing else happend, did the switch burn out?

Please help!

Thank You.

There are often multiple points at which current enters an HVAC system.

Be careful.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.

 

[Arfa Daily]

"b" <reverend_rogers@yahoo.com> wrote in message
news:1164278349.614423.199500@j44g2000cwa.googlegroups.com...

Arfa Daily ha escrito:

"b" <reverend_rogers@yahoo.com> wrote in message
news:1164233121.094084.21630@k70g2000cwa.googlegroups.com...

Arfa Daily ha escrito:

Hi

Has anyone got schematics for an Aiwa MX-Z9500MK that they could
either
have
a look at for me, or scan ? Need to know how the VFD filament supply
is
derived - and before everyone rushes to say " I think it's via a cap
",
in
this Aiwa model, it's not.

Thanks


Nothing listed for this model. I'm not desperate, as the system is not
worth
that much, but as it was apart on the bench, and I had sorted the
missing -24v problem, it was a bit annoying that I still had trouble with
the filament supply. This appears to be switched with a couple of
transistors near to the -24v reg. They actually derive the -24 on this
model, direct from a rectifier, rather than by the more traditional Aiwa
voltage multiplier. I don't really know why they bother switching the
filament supply to unused displays when the unit is off. Possibly to
preserve their life, I guess, but I have seen plenty of units where the
filament supply is always on. Anyway, having found these transistors, I
went
looking for a control signal, but I couldn't find anything in the area
that
moved when you switched from standby to on. There is a little surface
mount
digital transistor that looks as though it ought to control this lot, and
what should be the base leg, has print disappearing off towards the front
panel, but as I say, no movement of voltages around it. Just for sport, I
tried shorting across the switch transistor, and this immediately
restored
filament volts, and display on the amp, but still no filament volts up
the
bus to the graphic, so that remained dead. That was the point that I
called
it a day, and posted the request just to see if anyone had a manual.

No matter though, I have wrapped it back up now, and told the shop that
booked it in that the only way that it is going ahead, is if a service
manual could be found. They have indicated that they don't think that
their
customer will want to be bothered, so it will finish up now as just
another
of those jobs that end up only just about covering their time ... Thanks
for
the suggestion anyway.

Arfa

I've generally found mini systems horrible things to work on. if it's
not dismantling the thing to access the front bit, its the awful audio
output stages and board layout etc. Often, for anything more
complicated than cap replacement, mechanical or electro- mechanical
stuff, a service manual seems to be the order of the day.....
good luck
-B

Yep, know what you mean, This one is actually a big stacking 5-piece, about

the same size as those hateful Kenwood stackers that were so popular a few
years back, but still it is a pain to work on. To do anything to the main
board in the amp unit, it has to come out, which involves removing the front
and back panels. Happy days ...

Arfa

 

[bz]

lsmith2660@aol.com wrote in news:1164294597.995724.139640
@j44g2000cwa.googlegroups.com:

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

When I opened up where the switch is located it made a spark and then
nothing else happend, did the switch burn out?

Please help!

From the level of knowldege about elecricity evidenced by your question, I
would strongly recommend that you have a licensed repairman fix it.

I know of cases where the homeowner was electrocuted while trying to fix
such things, and one case where a licensed air conditioning repairman was
electrocuted while working on an air conditioning system.

If you knew more about what you were doing, the answer might be different,
but it sounds like you have no idea what is going on.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

 

[James Sweet]

lsmith2660@aol.com wrote:

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

When I opened up where the switch is located it made a spark and then
nothing else happend, did the switch burn out?

Please help!

Thank You.

Sure you can replace it yourself, however from what you've said here, it
sounds like with your level of experience you should call an
electrician, or at least get a book on home wiring. This isn't something
to be poking around in blindly.

 

[Mike]

David Naylor wrote:

Mike wrote:
David Naylor wrote:

Mike wrote:


Set will not power up. Has 162V on primary of switching transformer.
Nothing on secondary. No shorts evident in secondary.

Thanks for your help. Mike.


change out the buffer q 507 i belive and the zenor d 507 and the opto
look for puffed caps in the deflection board , what happens is the
buffer leaks and sends the b + up to 200 plus, on a 127 line caops
don;t like that.


Unfortunately can not locate Q507 or D507.

Thanks.

Sorry about that in this model it is ic1702 q 1705 and d1703

Hi David! Thanks a lot.
Your information is very helpful.
Can you provide part numbers for IC1705, Q1705 and D1703?

Thanks.

 

[t.hoehler]

So, here's the connection: Electroincs repair=high blood pressure=eat
dark
chocolate=lower blood pressure=repair electronics.
So I'd say it's a valid post hehe.
req

Quite so. I _always_ keep an ample supply of dark chocolate on hand when I

am repairing electronics junk. Really helps! Even better if you wash it down
with beer.
Tom

 

if you do not know how to replace a standard wall switch, CALL A QUALIFED
SERVICEMAN!

else,

if it is the main emergency on/off switch (usually in a red box covered
plate), then

FIRST, find the main circuit breaker for the furnace/heater at the mains
box, shut that circuit OFF

then replace the emegency switch with an exact replacement, consult with
hardware store guys abt this.

LAST, evacuate your home of alll valued possessions and living creatures,
then turn the circuit back on.

next, test the new switch, if system remains non-functional, CALL A QUALIFED
SERVICEMAN!

if you dont know what you are doing, CALL A QUALIFED SERVICEMAN! it is
cheaper than explaining to the judge how you blew your house and
neighborhood up.


<lsmith2660@aol.com> wrote in message
news:1164294597.995724.139640@j44g2000cwa.googlegroups.com...

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

When I opened up where the switch is located it made a spark and then
nothing else happend, did the switch burn out?

Please help!

Thank You.

 

R! wrote:

I was just thinking are you shure it is the oscillator ?

Tune near the bottom of the band take another radio and try to tune to
the oscillator probably 455Kcs above tuned frequency, listen for a dead
spot with a little background noise, that changes when the dial is
rocked slightly on the defective radio. Do this while the radio works
then chill it and see if you can still tune the oscillator or not,
don't change the dial on the now cold radio.

Yes, did that and the oscillator definetly stops at low temperature.
Measured HFE was 75 so I switched the oscillator transistor with
another germanium with HFE of 220. Performance improved, but oscillator
still stops at 40 degrees F or lower. I also switched the last IF with
a high gain silicon and adjusted the bias and retuned the coils.
Performance again improved, but radio still has noise problems on weak
stations. The signal trimmer capacitor peaks near the center of the
range, so I'm pretty sure the front end is aligned correctly. The noise
must be coming from one of the IF stages.

If I can fix the noise problem, the thing should work as good as new at
moderate temperatures.

-Bill

I had a problem similar to this and it was a bad IF transformer
worked fair when warm got worse as temperature droped and guit
completely at aproximately 25 deg. F.

If it worked with gernamium transistors at one time when the defect is
repaired it should function without major modifications, which would be
necessary with the change to silicon transistors.

Hope you understand what I am saying.

R!

 

[Homer J Simpson]

<wrongaddress@att.net> wrote in message
news:1164347560.855704.61260@j44g2000cwa.googlegroups.com...

Yes, did that and the oscillator definetly stops at low temperature.
Measured HFE was 75 so I switched the oscillator transistor with
another germanium with HFE of 220. Performance improved, but oscillator
still stops at 40 degrees F or lower. I also switched the last IF with
a high gain silicon and adjusted the bias and retuned the coils.
Performance again improved, but radio still has noise problems on weak
stations. The signal trimmer capacitor peaks near the center of the
range, so I'm pretty sure the front end is aligned correctly. The noise
must be coming from one of the IF stages.

Check the voltages on the bases of the first one or two transistors at
different temperatures. Check all of the resistors - if you have a low
voltage meter that can test without turning the junctions on use it.

 

[William R. Walsh]

Hi!

My question has to do with the on/off switch to the whole system. Can
you repair the switch yourself if it is not working, by buying a new
switch and replacing it. Or do I need to have an electrician since it
is a major applicance?

Most of these systems are pretty straightforward in operation. It would help
to know what you have...brand, type, model, etc.

Also, where is this switch? Is it on the thermostat or somewhere else? I've
seen furnaces that had a light switch wired inline on the AC supply in order
to facilitate turning the furnace on or off.

Be sure to be careful! Turn the power, gas and anything else supplying your
furnace off before you work on it. If you don't think you can work on it
safely, call someone to do the work for you.

William

 

hapticz@sbcglobal.net wrote:

if you do not know how to replace a standard wall switch, learn how to
do it first. Its very simple. Any person of normal intelligence can
learn to do it easily.

if you dont know what you are doing, CALL A QUALIFED SERVICEMAN! it is
cheaper than explaining to the judge how you blew your house and
neighborhood up.

how on earth is replacing a switch going to blow the neighbourhood up?
If you've found some clever way, you best go into hiding before the
terrorists find out.


NT

 

wrongaddress@att.net wrote:

R! wrote:

I was just thinking are you shure it is the oscillator ?

Tune near the bottom of the band take another radio and try to tune to
the oscillator probably 455Kcs above tuned frequency, listen for a dead
spot with a little background noise, that changes when the dial is
rocked slightly on the defective radio. Do this while the radio works
then chill it and see if you can still tune the oscillator or not,
don't change the dial on the now cold radio.

Yes, did that and the oscillator definetly stops at low temperature.
Measured HFE was 75

then your problem certainly isnt the transistor.


NT

 

[Simoc]

Mark D. Zacharias wrote:

And while you're at it, lose the "top-posting" nonsense. No one elected you
sheriff of this one-horse town.

Nor you. Top-posting is not supported by netiquette, and has never
been.

If you don't have anything to say for the subject in question, don't
whine about a signature. Get a life. I'm not a sheriff, I'm a voluntary
worker. If I find you driving wrong side of road, I might complain,
even if I'm not a sheriff.

--
Top-posting not supported.

 

[Simoc]

Jim Land (NO SPAM) wrote:

So the unit arrived missing a pot? Better get the service manual, which
is easily available, according to Google:

Thanks for your suggestion, although it might be a bit expensive with
the costs of delivery to Finland...so I'm still hoping if it'd be
possible to go without it. But maybe it isn't :<

Thanks, however.

--
Top-posting not supported.

 

[Simoc]

Homer J Simpson wrote:

Concentric pots. The volume one is a pair of pots, on cheaper gear with a
power switch on back. VERY hard to find a replacement these days - I
remember Centralab used to advertise a system where you could snap a
combination of parts together to make up one of these.

Thanks for the info. If it's too hard, I might just substitute it with
a regular pot. But I still would like to know the pinout

--
Top-posting not supported.

 

[Simoc]

Mark D. Zacharias wrote:

First of all, what problem are you having? If the playback picture is
jittery or rolling, alignment might help. Severe misalignment would show a
number of horizontal bars of snow.

Yes, there are horizontal noise bars.

The slanted posts are not adjusted, the height of the rollers is.

Really? I've understood that the tape should go the correct path
without much support of the roller guides. Am I wrong? So is it only
the height of those roller guides that affects to the height of the
tape path?

A slotted
flat blade screwdriver is usually required.

Yes, there are screws that can be rotated with a slotted flat blade
screwdriver.

Older models have set screws
which must be loosened somewhat for the adjustment, then re-tightened. Newer
ones generally just have some tension built-in so that the post does not
rotate easily on it's own.

So are those small screws in older models just for locking the height
of roller guides?

Thanks a lot for your info

--
Top-posting not supported.

 

[Mark D. Zacharias]

Simoc wrote:

Mark D. Zacharias wrote:

And while you're at it, lose the "top-posting" nonsense. No one
elected you sheriff of this one-horse town.

Nor you. Top-posting is not supported by netiquette, and has never
been.

If you don't have anything to say for the subject in question, don't
whine about a signature. Get a life. I'm not a sheriff, I'm a
voluntary worker. If I find you driving wrong side of road, I might
complain, even if I'm not a sheriff.

Sorry, but there's too many top-posting nazis around usenet. Just to be
clear, this is a generic statement and not directed at you personally.

If you research the subject there are uses for top-posting, bottom posting,
and middle-posting, replying in the middle of the OP's message to each
question raised.

I usually bottom post, but I refuse to be preached at on the subject by
people who have no tolerance for such a small thing.

Back on the subject of your vcr however, yes, the white rollers with the
metal slotted chrome at the top are the adjustments. To start with, adjust
the height of the roller so that the tape is not curling along the lower
cylinder while playing. From that point try to center the adjustment for the
least jitter, rolling, or snow. When you are nearing the correct adjustment,
the number of bars will decrease then at some point the entire picture will
appear. When this happens there will be a small range of adjustment which
will show some snow or jitter on either side - try to center this area for
each roller.

Set screws almost always go at 90 degrees to the post. If the screw points
down, or has red paint on it, leave it alone.


Mark Z.