Toshiba TV29C90 problem; Image fades to black...

[Leonard Caillouet]

What was the problem?

Leonard

<dkuhajda@locl.net> wrote in message
news:1115173655.156752.316630@o13g2000cwo.googlegroups.com...

Yes and no. It will not blank due to an imbalance of the return pulse.
It will blank due to a problem on the AKB line, like railed at zero
volts or full voltage. Same thing I thought until I ran into the AKB
causing blanking due to a problem in the circuit on one of the newer
sets. The troubleshooting steps still applied, looking and verifying
the three AKB pulses coming up as the tube warms up. In my case the
AKB return pulses were never visible at all.

 

[John J.Turley]

gpolitis@gmail.com wrote:

I have a Marantz SR-7000 receiver that, after a recent move to a new
home, will no longer turn on. When plugged in, the red Stand-by light
comes on, but neither pressing the power button on the unit or trying
to turn it on via the remote work. Does anybody have any ideas?

As I mentioned I moved recently, but my home theater equipment always
gets moved by hand and quite delicately at that, so I don't believe
anything happened in the move.

I appreceiate any input you folks may have as to what might cause this
and what to try...

Thanks in advance!

Just a thought. Be sure the speaker load is on the amp (connected, no

blown speaker fuses or tripped speaker CB's). The amp may saty in
standby to protect itself.

 

[Mark D. Zacharias]

Mark wrote:

does the noise change when you move the volumne control?

does it work in record?

are the batteries good?

Mark

There is a record / play mode switch that needs to be cleaned. In the
meantime, put a blank cassette in there and put it into record mode, then
stop it, then record again, etc. Do this several times. It should work OK
for a while.

Mark Z.

 

[Ken]

Lockergnome1 wrote:

In trying to test the laser power supplies I mentioned in an earlier
post, I dug out my HV meter...it's a Heathkit, inherited from my great
grandpa. It didn't appear to be funcioning, so I disassembled it...In
the probe end, I found 2 large resistors, constructed of some material
printed in a spiral around a ceramic cylinder. Both were cracked at
one end (where they were screwed to the pobe tip and the rest of the
meter...possibly someone screwed the unit together with too much
force.) One was labelled as 800 megaohm (!!!) made by Beman Mfg. Inc,
Component Division. The other is unlabelled. Does anyone know where I
could obtain replacements, or what I could use instead (other than
1,600 1-megaohm resistors )

You might find it easier to buy a new HV probe. They are not all that
costly if I recall correctly.

 

[Gerard Bok]

On Wed, 04 May 2005 12:24:54 GMT, Ken <user@domain.invalid>
wrote:

Lockergnome1 wrote:

In trying to test the laser power supplies I mentioned in an earlier
post, I dug out my HV meter...it's a Heathkit, inherited from my great
grandpa. It didn't appear to be funcioning, so I disassembled it...In
the probe end, I found 2 large resistors, constructed of some material
printed in a spiral around a ceramic cylinder. Both were cracked at
one end (where they were screwed to the pobe tip and the rest of the
meter...possibly someone screwed the unit together with too much
force.) One was labelled as 800 megaohm (!!!) made by Beman Mfg. Inc,
Component Division. The other is unlabelled. Does anyone know where I
could obtain replacements, or what I could use instead (other than
1,600 1-megaohm resistors )


You might find it easier to buy a new HV probe. They are not all that
costly if I recall correctly.

The cheap ones can be very costly

--
Kind regards,
Gerard Bok

 

[Sam Goldwasser]

TA7205@aol.com writes:

Replaced laser pick up, error 11 ???? Pioneer DEH-2400

I don't get it. I pulled the working pick up out of this one to fix
another
deck (same model) Then, I ordered a new pick up and when it arrived
I installed it. Now, the disc spins, sled moves to center position and
laser makes 2 attempts to read, then displays error 11.

Pioneer DEH-2400
I need some feedback here.

Check for a solder blob or jumper that needs to be removed.

However, some/many/most? Pioneer pickups do not come adjusted when new.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
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Important: Anything sent to the email address in the message header above is
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contact me via the Feedback Form in the FAQs.

 

On 4-May-2005, "GanjaTron" <ganjatron@gmx.net> wrote:

Assuming this is a thermal problem, I poked around with cold spray in
there -- to no avail. None of the suspect components (regulators, etc)
reacted to cooling. Without schematics, I'm pretty screwed anyway...

If you are happy to dig into component level, there are probably a
couple or so of 6-legged opto-couplers in the DC PSU. might be
worth monitoring voltages across the LED's and their o/p to see
if they are respondingt to drive. The LED's are known to die.
That was the problem with my HP (Canon engine) laser. Ended
up putting in a 6-pin skt, and a red LED in series with the opto
LED drive. Now red LED lights in sympathy with the fuser lamp,
if fuser doesn't light diagnosis is simple.
..
You will probably find a service manual on the internet, try
http://www.eserviceinfo.com/
for starters, though there are other sites. You might have to
do a bit of digging on the ESI site as it's indexing seems a
bit flakey, may be ok when you get the hang of it.

Other than that it's a case of following logic level signals
and strategic measuring of voltages. Like does the fuser
lamp come on at start up, if not why? Does it start to
cycle?

 

[Ken]

Gerard Bok wrote:

On Wed, 04 May 2005 12:24:54 GMT, Ken <user@domain.invalid
wrote:


Lockergnome1 wrote:


In trying to test the laser power supplies I mentioned in an earlier
post, I dug out my HV meter...it's a Heathkit, inherited from my great
grandpa. It didn't appear to be funcioning, so I disassembled it...In
the probe end, I found 2 large resistors, constructed of some material
printed in a spiral around a ceramic cylinder. Both were cracked at
one end (where they were screwed to the pobe tip and the rest of the
meter...possibly someone screwed the unit together with too much
force.) One was labelled as 800 megaohm (!!!) made by Beman Mfg. Inc,
Component Division. The other is unlabelled. Does anyone know where I
could obtain replacements, or what I could use instead (other than
1,600 1-megaohm resistors )


You might find it easier to buy a new HV probe. They are not all that
costly if I recall correctly.


The cheap ones can be very costly

I did a search for probes, and you are right. The prices are much
higher than I paid when I purchased mine years ago. But he might look
at Ebay.
http://search.ebay.com/high-voltage-probe_W0QQfkrZ1QQfnuZ1QQfromZR8

 

[Mike]

as old as this thing is, and the heat over the years, it wouldnt surprise me
that the radial electrolytics in the power supply is leaking or dried.

I know this is a far cry from a fax machine, but I worked on a fax machine
with similar problems, Recapped the power supply, and all went away.


"GanjaTron" <ganjatron@gmx.net> wrote in message
news:1115037789.059181.223020@z14g2000cwz.googlegroups.com...

Hi folks,

has anyone out there ever managed to troubleshoot the DC power supply
in one of these dinosaurs? Mine's developed a fault in the 24V supply,
killing the fans and main motor < 1 minute after powerup. Input from
the AC module remains stable (220VAC) , as does the 5V output since the
panel still functions and gripes about a "SERVICE 55". According to the
service manual, 55 indicates a DC controller error, but I've ruled
that out since the 24V output from the DC PSU still drops after
detaching the DC controller.

I'd appreciate any comments on diagnosing this baby on the component
level. Sure, replacing the entire module is a piece of cake, but hardly
worth the cost when I can get an LJ4+ for the same price (which of
course isn't quite as rock solid)...

Thanks 'n' stuff!

--GanjaTron

 

[Art]

Got a TV there with very little support from the manufacturer as far as
parts or service literature. Many retailers have resorted to just exchanging
them if they are still in warranty. You will either need to do some in-depth
diagnosis or pay someone to do it for you. Open fuse, blown transistor,
open resistor, etc.
"migi" <migi207@yahoo.com> wrote in message
news:1115244563.736124.238540@o13g2000cwo.googlegroups.com...

Ok so my TV just turns off one afternoon for no reason and and now I
cannot turn it back on. It is about 4 months old so it is relatively
new. The power indicator does not turn on so I am thinking that it has
to do with the switch. Anyone had problems with this before what should
I do. They will charge me about $50 dollars for one way shipment and
manual labor if I send to the manufactor, which would be what the tv
cost me!!! Any Ideas, I opened it and the switch looks fine to me,
nothing burned or rusted.

 

On 5-May-2005, "GanjaTron" <ganjatron@gmx.net> wrote:

The fuser draws its power from the AC PSU, right? I doubt that's the
problem though, particularly when both fans are dead.

Yes, fuser (in mine) draws power from AC PSU. There is a power
board and a logic board in the AC PSU (Canon SX), and the DC PSU
feeds it with assorted signals. The logic board has a fattish resistor
of 1K2 driving the power boards opto-coupler, the one I added an
extra LED in series. Opto drives triac, with the extra red LED,
LED goes on/off, triac goes on/off, fuser lamp goes on/off. Now
it's easier to trouble shoot. AC PSU also has a relay in series
with mains supply to triac. I found I could short it out for testing,
so I put a domestic lamp in place of the fuser lamp, set it up
on a table, and drove it with a 9V battery and resistor, for testing.
Saved installing and uninstalling the PSU all the time.

DC PSU has opto couplers, there is an isolated switch mode,
raw AC in. It's txfmr drives all the rectifiers, logic etc, there
are output V level sensors, and their o/p feeds back to the
isolated switch mode. So we have a mains side, and
an isolated logic side.

 

Lockergnome1 <lockergnome1@earthlink.net> wrote:

One was labelled as 800 megaohm (!!!) made by Beman Mfg. Inc, Component
Division. The other is unlabelled. Does anyone know where I could
obtain replacements, or what I could use instead (other than 1,600
1-megaohm resistors )

800 2 megohm resistors.

Seriously... Mouser (and I _think_ Digi-Key) carries Ohmite "Mini-Mox"
(normal resistor shape) and "Slim-Mox" (flat plate) high value resistors.
A 750 M, 5 kV, 1 W resistor is $6 quantity 1 and is about 0.9 inches
long by 0.17 inches around. They don't list an 800 M part - perhaps
you could adjust the meter calibration to compensate.

There are a few Heathkit schematic sites around if you need to find
a value on the unmarked resistor.

Matt Roberds

 

[Art]

Did you take the horiz drive transformer out, clean it's solder legs and
check the coils in it? Then resolder it, or a replacement, to the circuit
board? Resolder the LOPT and associated connections. A good magnifying glass
may assist in finding other suspected poor solder connections. Otherwise,
the set may be going into protect mode, over voltage or over current.
"drradio1" <drradio1@sbcglobal.net> wrote in message
news:1115283158.527211.125080@o13g2000cwo.googlegroups.com...

The set came in dead relay click only, we replaced the damaged
regulator, the HOT and the fusible resistor and resoldered the
transformers.. the set ran OK for a week now the video will go out once
in a while or the set will come on with no video audio OK.. When the
set comes on with no video we have no HV, screen voltage or filament
voltage, we turn the set off and back on again and it works fine..Any
help would be appreciated..Thanks for your time
Robert..

 

[kip]

You bought cheap you got cheap.
Next time buy a Real TV

kip
"migi" <migi207@yahoo.com> wrote in message
news:1115244563.736124.238540@o13g2000cwo.googlegroups.com...

Ok so my TV just turns off one afternoon for no reason and and now I
cannot turn it back on. It is about 4 months old so it is relatively
new. The power indicator does not turn on so I am thinking that it has
to do with the switch. Anyone had problems with this before what should
I do. They will charge me about $50 dollars for one way shipment and
manual labor if I send to the manufactor, which would be what the tv
cost me!!! Any Ideas, I opened it and the switch looks fine to me,
nothing burned or rusted.

 

[Sam Goldwasser]

"Lockergnome1" <lockergnome1@earthlink.net> writes:

Right again! I had been trying it w/ a 9v battery, nothing from the
laser tubes, but it can still give a pretty nice shock. Tonight I
hooked up one of the supplies to a head and a 12v power supply I had
laying around...No lasing but the tube did light up...blue
(noncoherent) light came out the ends so it's def. not a good tube
but I've got 19 more where it came from to try...not keeping my hopes
up though, some of them had test dates written on them...1973...and not
all of them were good even then.

It is most likely not a good tube but it's also possible the mirrors
are misaligned since that is determined by how the end plates are
mounted. You'll notices that they don't sit flush.

If you noticed my other post, my HV meter is out of comission at the
moment...but since the tube lights up I figure I got the input voltage

Yes, sorry about that. Probably should have warned you about the starring
voltage - 8 kV or more.

right. Don't know if the heads or the power supply have starters built
in though...or is the higher starting voltage just something that

In the power supplies.

happens naturally w/ the power supply?
On another note, the supply I mentioned before that I was able to peel
some rubber from...I worked on it some more and got a good amount
off...If you want to take a look at it or know more about it for your
reverse-engineering endeavours, let me know

Yes, definitely would be interested in a reverse engineerable power supply.

Thanks.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Do Little Jr.]

"RonKZ650" <RonKZ650@aol.com> wrote in message
news:1115269063.013979.300980@z14g2000cwz.googlegroups.com...

The old bad switch trick, yep every time a set is dead it's "the
switch", simple, simple. I'm glad to be in a business that all day long
all we see bad is "switches". Rant, but the truth, NOT.

Yep, there certainly are days like that....

As for cheap Apex TV's check the startup diode!
It is located (from memory) between the 24 V line
and the start up 12 (or 15) V supply line. This known bad
diode 'on startup' supplies the voltage to the hor. oscillator.
It is a common fault with those cheap Apex and it makes
for an easy buck.... estimated repair time less than 30 minutes.

Happy trouble shooting!

 

[dannyg12]

DFerree923 Wrote:

I have an older Pioneer VSX-502 receiver that got hit by lightning
through the
AC line. Everything seems to work, except for the radio tuner. All
fuses are
ok. I have already replaced the LM7001 chip, and the TC9164N (Pioneer
suggests
these to be the problem after a strike through the antenna). Still, no
radio.

I can get a "thumping" sound (oscillation) through the speakers when in
AM
mode, but nothing in FM. Also, there are two indicators in the
dislplay for
"tuned" and "stereo". Neither one is lit, except for when the board
that
contains the LM7001 chip is removed(?), then they both work, but
obvivously no
radio without the antenna card.

One other problem is that when the volume is increased past 1/3 of the
way,
there is a relay click (overload protect?), and the speakers cut out.
Any
suggestions welcome.

TIA,
Del

Sounds like you have the same problem that I have with mine, no radio.
Did you ever get it fixed?
dannyg12


--
dannyg12

 

[sofie]

migi:
If, indeed, the problem is with the power switch (which it almost never is)
then you should be able to
turn on your television with the remote control
thus bypassing the switch altogether.
Most likely there is a fault in the circuitry that would require a
technically inclined person to troubleshoot and repair...... at the very
least you should TAKE it to a service shop for at the very least a repair
cost estimate so you can make a service decision with fact instead of
Internet or telephone wild guesses.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"migi" <migi207@yahoo.com> wrote in message
news:1115244563.736124.238540@o13g2000cwo.googlegroups.com...

Ok so my TV just turns off one afternoon for no reason and and now I
cannot turn it back on. It is about 4 months old so it is relatively
new. The power indicator does not turn on so I am thinking that it has
to do with the switch. Anyone had problems with this before what should
I do. They will charge me about $50 dollars for one way shipment and
manual labor if I send to the manufactor, which would be what the tv
cost me!!! Any Ideas, I opened it and the switch looks fine to me,
nothing burned or rusted.

 

[Nitroflea]

http://home.telkomsa.net/flipflop/photos/camera/72_3.JPG

Here is an image showing the complete package that comes with the
camera.
If you look at the center of the image, between the batteris, tapes,
and camera, there is an black box with to yellow RCA plugs. That is
the RFU-85 adaptor.

 

[Nitroflea]

I just learnt that the different adaptors came with the different
models.

An RFU-85 and RFU-86 also exists that have similar functions.