Still need help Toshiba TV CN30C90 dead

[Roy and Rosa]

I posted earlier for help on this Toshiba cn30c90.
I dont have a schematic so I dont know where to check for the standby volts
or 60 hz clock. Im not able to trace it.
Also what pins on jungle IC to check. It uses TA8870AN.
I still think I may have a problem in the primary of the SMPS.
Anybody have info on the regulator STRS6501?
When I scope outputs of SMPS and plug set in...
voltage ramps up to about 52 vdc in approx. 300 millisecs then slowly decays
when oscilliation stops in primary.
" " " " " 9 vdc " " " "
" " " " " " "
..
Thanks again Roy

Here are some snips from previos posts:
*****************************************

Have you checked the HOT ?

I.

No blown fuses.
Hot is good as well as the flyback. Problem is in the SMPS or associated
circuit. When I jump the ac relay which provides power for B+(with HOT
removed), T862 clicks like it has a short in the secondary but it only draws
about 400 milliamps. But I can not find any shorted diodes. I get 115vdc at
C884 and 20vdc at C889 which doesnt seem too high.
Anyone know what voltages I should see at the hybrid regulator STRS6501?
Anyone have a scan of the service manual or schematic?
Thanks Roy

If you have 115v on the secondary, you do not have a short in the
secondary of the smps.
It is probably clicking because the smps is in effectively an unloaded
condition as the horizontal is not running.

Start at square one with the basics and work your way down from there:
1. Standby voltage to system control and the 60Hz clock pulse from ac
line.
2. Turn on signal from system control, possibly both to relay and on
I2C data bus.
3. Horizontal run Vcc
4. Horizontal drive pulses out of jungle ic
5. Horizontal drive to the base of HOT
6. Main B+ to the collector of HOT
7. Then troubleshoot the reason for the shutdown, lower the B+ to the
flyback system with a resistor or light bulb and scope the flyback
waveforms.
8. Then work back to the must have feedback signals, x-ray protect in
line, h-sync return, v-sync return, I2C all ok return from misc ics,
etc.
******************************

 

[Roy and Rosa]

My local tv shop let me borrow the service manual.
Turned out to be a bad 5 volt regulator. A L78MR05.
Sound is bad though. I need to find the audio amp and processor. Toshiba
no longer has them.
Roy

 

[[email protected]]

Audio bad on A/V inputs or just the tuner?
Just the tuner, replace the SBX module inside the mts decoder can.

 

[Roy and Rosa]

Audio bad on A/V inputs or just the tuner?
Just the tuner, replace the SBX module inside the mts decoder can.

Well I scoped signal at TA8792n, some type of sound processor. I have what
looks like an audio signal going in but not coming out on left or right
channel. The subwoofer out signal seems to be good and I have sub woofer
signal to speakers. I believe it is this sound processor that is bad. But
I was going to order the audio amp module at the same time. not too
expensive.
I havent tried an audio signal input yet but since it seems to be good
from tuner I think it is the ta7892. Ill try a vcr tomorrow though.
Thanks Roy

 

[Jason D.]

Well I scoped signal at TA8792n, some type of sound processor. I have what
looks like an audio signal going in but not coming out on left or right
channel. The subwoofer out signal seems to be good and I have sub woofer
signal to speakers. I believe it is this sound processor that is bad. But
I was going to order the audio amp module at the same time. not too
expensive.
I havent tried an audio signal input yet but since it seems to be good
from tuner I think it is the ta7892. Ill try a vcr tomorrow though.
Thanks Roy

Trust me, Roy, replace that SBX module inside that tin box. SBX
module is small module on stand up pins. It's very common part and
readily available, inexpensive. I did several like this.

Cheers, Wizard

 

[Roy and Rosa]

Trust me, Roy, replace that SBX module inside that tin box. SBX
module is small module on stand up pins. It's very common part and
readily available, inexpensive. I did several like this.

Cheers, Wizard

Set worked perfectly today when I turned it back on. Is that a symptom of
the SBX module?
Roy