Bush WS6674 grey raster with f/back lines - no sound

[Les Woollam]

OK, PSU seems to be OK - I was measuring the voltages using the incorrect earth as reference
All voltages are now virtually spot-on, apart from the 8VD rail which is measuring 12.4.
Back to the drawing board.. . any ideas????

[Guest]

If the main PSU measures Ok. What does the Line Output Transformer measure like??

[Les Woollam]

Unfortunately, I have no way of measuring the EHT
The TV seems to have 'settled into a pattern'. . . on power-up, I get picture + sound (+ teletext!), but certain functions don't work. For example, the Prog and volume buttons on the front panel don't respond (Prog change on the remote works fine). On the remote, volume/menu/timer don't work.
This gets stranger by the minute

[Guest]

These type of problems could be a dried up capacitor or a failing connection or even something else. You could spend hours checking all of the solderjoints with a microscope or testing all of the electrolytics with an ESR meter.
The voltage for the sound chip usually comes from the LOPT so if you get raster and no sound............ (it is not in the p/s circuit) [do you get the sound volume voltage?]
When the set is faulting you need to take waveshapes from various positions to give you a clue to where the problem is.

[Les Woollam]

I think I’m getting a little closer to nailing this one!
The TV now works kind of OK, but only prog change, text and standby work on the remote. . . the front panel switches do not work, but all ‘meter’ OK.
There is a slight lack of picture height.
I’m wondering if this could still be power supply related – possibly ‘dirty’ rails which still read the correct voltage?
Sound is OK, but volume cannot be adjusted.

[Guest]

It could be power related, there are filter capacitors after the rectifier diodes and usually small electro's on the power in, of the IC's. It could be a bad solderjoint or hairline crack across a track. Maybe it is a faulty IC itself?
If you don't have a scope or ESR meter, maybe you could try replacing all of the electrolytics around all of the IC's? Or go over all of the solderjoints with your iron.
Replace all of the electrolytics around the verticle output IC heatsink. If one is right next to or inside of the heatsink mount it underneath the board if you have room.
If the front panel buttons plug into the main board, unplug them, lubricate the pins and re-insert the plug.
There is a site that may have some information or ideas that will interest you www repairfaq.org/sam/safety.htm
Good luck!