SHARP 28LW92H - VESTEL 11AK45

[buffy]

 :ciao: Hi...

Got one of these in, problem.....  Switch on you get green led, red led, green led, red, etc..... tripping?? inspection of board - nothing jumping out, no burning....  cant SEE any dry joints, but there again i am very old nowadays :laugh1: eyesight gone  :loool:  Come on GUYS you must have had this one its a crappy old Vestel!!!  :wallbash:
carol

[norman]

Hi Carol, check the diode that supplies the 150v for the line output stage it may be s/c,can't remember the circuit ref,also any other feed diodes in the power supply. Line output transistor worth checking also diodes around line output stage. Hope this helps,Norman

[buffy]

Norman,
The diode (D112) reads high one way lower the other!! i think that meant it was OK?? Its been a long while since i got my C&G, forgotten a lot!!! work in a shop these days  :blush: checked the diodes in the LOPT area - all 'seem' OK  :dry: oh well, another one for the tip  :sad:
carol

[brainstorm]

Hi carol,
You need to establish if your power supply is working, have you got HT?
If you suspect power supply then IC106 MC44608 is known to fail.check R130 for drys.Check R152 O/C
If PSU  ok then I would check LT feed resistors to Field stage they are usually 0.22 or 0.47 ohm
if they have failed then your Field IC may have failed.
I assume you have checked the Line output transistor for S/C
Failing this I think you need to do some voltage checks to narrow down the causes.

[buffy]

Brainstorm....
Checked around, it appears that HT 200V is present, etc... but low voltage to the EEprom etc, is not comes up as 10V on the Reg, then drops to 2V - so... LV Fault i suspect, i wonder if the EEPROM is faulty??? cant see any drys anywhere, but i dont have good light and i am old and blind these days!!!  :chok:  :blush:
carol

[buffy]

As it appears to be something i cant 'see' i assume its a chip or MOSFET, CHS do a PSU repair kit, maybe i will keep the set and fit that sometime in the future  :mellow: Still a goody i think  :unknw:

[BC109]

If you have 200v to tube then most is working??
EEPROM has been known to be trouble AK45. Pop in a blank one and see what happens. Options will be wrong but will prove the point.

[buffy]

I dont have a blank EEPROM, or any way of programing one etc..... i took it out completely and the fault remains.  :dry: anyway i will unemployed after xmas, so no chance of doing anything about anything!!!