Sanyo DS31590 vertical problem

[Chuck]

Hi all. I inherited this set from a tv repairman who
was closing up shop. He couldn't repair it so I
decided to give it a go. The picture has vertical
fold over at the top and is pulled up from the bottom.
I've replaced all the electrolytic caps in the
vertical circuit and the jungle, eeprom , and vertical
output ics. Other capacitors in the vertical circuit
have been subbed. Resistors have been checked in
circuit and appear to be within tolerance. Adjusting
the vertical parameters in the service menu doesn't
change the symptoms. The capacitors in the pincushion
circuit that can affect vertical height have been
subbed. If anyone has ever seen such a problem with
this chassis, I'd appreciate their assistance.
Thanks. Chuck

 

[john]

Keep checking ,you have missed the 2 bad caps.

kip

 

[chuck]

Unfortunately, this isn't a normal capacitor problem though the
symptoms are the same. I have a schematic and over 30 years of repair
experience but thanks for the suggestion. Chuck

 

[Sofie]

Chuck:
Have you done a ring test on the vertical deflection coils in the yoke??
Also check any of the diodes in the circuitry..... etc.

 

[Jerry G.]

If you are very sure that you ESR checked, and replaced ALL the bad
caps, then the only thing you have left are some base components, and
the deflection yoke.

The caps you missed are the bad ones... I am convinced that you still
have a bad cap in this one, or the deflection yoke is defective. In
some sets, there are some small caps, and or thermo resistors in the
deflection yoke for compensation. This may not be the case for this
set, but it is a thought. I have had resistors go sort of opened in the
deflection circuits causing this type of fault as well.

But... I am still sort of convinced by your description, and by past
experience there is a cap or two that you missed!

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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Hi all. I inherited this set from a tv repairman who
was closing up shop. He couldn't repair it so I
decided to give it a go. The picture has vertical
fold over at the top and is pulled up from the bottom.
I've replaced all the electrolytic caps in the
vertical circuit and the jungle, eeprom , and vertical
output ics. Other capacitors in the vertical circuit
have been subbed. Resistors have been checked in
circuit and appear to be within tolerance. Adjusting
the vertical parameters in the service menu doesn't
change the symptoms. The capacitors in the pincushion
circuit that can affect vertical height have been
subbed. If anyone has ever seen such a problem with
this chassis, I'd appreciate their assistance.
Thanks. Chuck

 

[chuck]

I've replaced diodes, tested all resistors out of circuit and replaced
all capacitors so I think you are right about it having to be the
yoke. My ringer is at work so I will take it home tonight to do the
test. I haven't seen a yoke cause a problem like this since tube bw
sets were common. Thank for your help. Chuck.

 

[chuck]

The problem turned out to be the yoke which is only available with the
crt. Thanks for the help. Chuck