A while back my dad had a problem with his TV losing colour intermittently. I immediately suspected a fault with the TV (I believe it's a JVC built by Vestel) but after loaning him a 32" LCD, the same problem occurred. So, the problem was clearly with the video source - the Echostar DVB Freeview receiver.
First impressions - Very well built. Nichicon and Panasonic electrolytics across the board. On board mains PSU (I like it better than wall wart.) Labelled test points. Designed in UK. Single chip MPEG Freeview solution (ST OMEGA.)
When I got it to test it powered up fine, but after a few minutes the sound went away, then the picture froze. Then the box locked up entirely. I also noticed a strange hissing/buzzing sound from the unit, almost like burning components (but nothing was excessively hot.)
After unplugging it and plugging it back in again, it did the same a couple of minutes later, then it wouldn't power up at all.
Thinking about the colour problem I cleared up a few of the joints on the SCART connector. I redid a few other joints, they were all fine. I checked all the electrolytics - not a problem. Hmm...
Eventually I noticed a little burn mark near the tuner can between two pins. A path of conductive residue had built up here (I'm not sure how) and this was the cause of the burning sound. The board was a little discoloured around the area. It was shorting the +30V for the tuner out to ground, but only occasionally. This was causing the PSU voltages to dip, causing the box to do a whole load of freaky things.
Another strange one fixed...
First impressions - Very well built. Nichicon and Panasonic electrolytics across the board. On board mains PSU (I like it better than wall wart.) Labelled test points. Designed in UK. Single chip MPEG Freeview solution (ST OMEGA.)
When I got it to test it powered up fine, but after a few minutes the sound went away, then the picture froze. Then the box locked up entirely. I also noticed a strange hissing/buzzing sound from the unit, almost like burning components (but nothing was excessively hot.)
After unplugging it and plugging it back in again, it did the same a couple of minutes later, then it wouldn't power up at all.
Thinking about the colour problem I cleared up a few of the joints on the SCART connector. I redid a few other joints, they were all fine. I checked all the electrolytics - not a problem. Hmm...
Eventually I noticed a little burn mark near the tuner can between two pins. A path of conductive residue had built up here (I'm not sure how) and this was the cause of the burning sound. The board was a little discoloured around the area. It was shorting the +30V for the tuner out to ground, but only occasionally. This was causing the PSU voltages to dip, causing the box to do a whole load of freaky things.
Another strange one fixed...
