Hi all,
I've been attempting to repair my first TV, a Teac CT-M805SV, I've made the problem better, but its still there so I'm hoping for some pointers.
The problem its exhibiting is a lack of picture width (partial horizontal collapse?) with a fairly bad pincushion problem, which I suspect will sort itself out when I fix up the picture width problem.
Anyway, I've replaced a number of caps around the vertical section since that sounded like a good idea, and also fixed a few cold solder joints in the PSU and around some diodes near the LOPT/flyback. I've also tested all transistors in the area (as best I can - a go/no-go type test), and checked all the diodes on the main board.
So far all my efforts have achieved is to make the problem about 50% better than it was. I noticed when I was testing it after replacing caps in the vertical area that the picture was creeping inwards (getting narrower) within about 5 seconds of turning on the set, so I promptly turned it back off.
I replaced as a precaution a couple of diodes that were running hot, and one capacitor that was adjacent to one of those diodes as it had been scorched by the diode beside it. The diodes were still functional, however.
Here's what I've done to date:
Replaced D403 and C431 (D403 was hot, scorched C431)
Replaced D401 (damper diode) as it had been running hot and had blackened the PCB underneath it. It also had dry solder joints at both of its pads.
Replaced C419 (4.7uf 50v Bi-Polar), C401 (1uf 50v), C408 (100uF 35v), C410 (330uF 50v) and as mentioned above, C431 as well.
I don't know where I should actually be looking for this problem on the PCB/schematic, so if anyone can point me in the right direction that would be great! :) I've been contemplating testing the voltages of the PSU while its running which will probably be my next step if I don't any better suggestions.
Thanks.