I suspect this elderly set could be described as a coronavirus victim, as it has probably had more use in the last 6 weeks than in as many years!
"It was fine yesterday" was the comment from the owner, as if TV's are supposed to give some advance warning that they are about to die.
I was greeted with the 4-blink led code which I remembered was likely to be backlight related. It's a CCFL backlight so no open circuit LED's to look out for this time.
This particular set was assembled in Spain, I have noticed before that the soldering in Spanish-built sets leaves a lot to be desired. This one didn't disappoint, they all look dry and grey.
Once inside and with the screening plate off the inverter boards it was immediately obvious that there was a dark area around one of the solder-in fuses. There was also a damp patch on the lower corner of the upper board. F3 was black and o/c.
I read on another forum that it's not uncommon for these fuses to die for no apparent reason so I bypassed it with a very thin "jump lead" (about 1Ω resistance), tried the set again and it started up. I let it run for a minute or so while looking for smoke then powered it off. I noticed my 'jump lead' was quite warm so this time I put an ammeter across the fuse. 4.96A!! Again I let it run for a bit, powered off again and checked for warm components. None of the transformers were warm but one of the 220uF cap's (C604) almost burnt the tip off my finger. And funnily enough it was close to the 'wet patch' I mentioned earlier. Some of the others were quite warm too so I'm guessing they are a bit leaky - in more ways than one in 604's case.
Now had these been ordinary electrolytics wrapped in a plastic sleeve I would have no hesitation replacing all 20 of them but these are all metal cans, so my question (eventually!) is do these cap's differ in any great way from the ordinary plastic-wrapped ones (of which I have plenty)??
TIA.
"It was fine yesterday" was the comment from the owner, as if TV's are supposed to give some advance warning that they are about to die.
I was greeted with the 4-blink led code which I remembered was likely to be backlight related. It's a CCFL backlight so no open circuit LED's to look out for this time.
This particular set was assembled in Spain, I have noticed before that the soldering in Spanish-built sets leaves a lot to be desired. This one didn't disappoint, they all look dry and grey.
Once inside and with the screening plate off the inverter boards it was immediately obvious that there was a dark area around one of the solder-in fuses. There was also a damp patch on the lower corner of the upper board. F3 was black and o/c.
I read on another forum that it's not uncommon for these fuses to die for no apparent reason so I bypassed it with a very thin "jump lead" (about 1Ω resistance), tried the set again and it started up. I let it run for a minute or so while looking for smoke then powered it off. I noticed my 'jump lead' was quite warm so this time I put an ammeter across the fuse. 4.96A!! Again I let it run for a bit, powered off again and checked for warm components. None of the transformers were warm but one of the 220uF cap's (C604) almost burnt the tip off my finger. And funnily enough it was close to the 'wet patch' I mentioned earlier. Some of the others were quite warm too so I'm guessing they are a bit leaky - in more ways than one in 604's case.
Now had these been ordinary electrolytics wrapped in a plastic sleeve I would have no hesitation replacing all 20 of them but these are all metal cans, so my question (eventually!) is do these cap's differ in any great way from the ordinary plastic-wrapped ones (of which I have plenty)??
TIA.
Attached Files