Re: Bad Viewsonic LCD monitor
The PSU output was 17.5 volts. A little below the rated output of 18V, but well within 5%.
I visually checked the caps in the PSU; they are 1000uf Rubycon's (I don't recall the voltage rating). I don't have an ESR meter (yet) and my capacitance meter only goes up to 20 uf. Replacing the caps did cross my mind, but I first wanted to verify the problem wasn't occurring on the logic board.
NOW things are getting even screwier. As an aside, I've been working with electronics for more than 40 years. When I got started radios had tubes! I prefer 'broken' equipment to remain broken until I replace the defective part. As one of my friends said "Equipment that fixes itself will break itself, usually at the most inconvenient time possible".
After replacing the fuse, the shield over the PSU and logic board was replaced and the monitor hooked to a computer running Windows XP. As noted, it failed after half an hour (this happened twice, the second after it was unplugged for more than 12 hours). The test with the replacement power supply was done with the shield off. To verify it was the original power supply I hooked that back up (left the shield off) and let it run for a couple of hours. No problems!! I put the shield back on and again it ran for several hours without problems. On the hottest day of the year. The only variables are the additional run time and the computer it was hooked to.
It IS a bear to get the back off the monitor. I would prefer to get it fixed for SURE before putting the back on again. I hope to have this as my main monitor. Am I right to assume that replacing the two caps in the PSU would be a reasonable precaution?
Thanks,
PlainBill
Originally posted by eguevarae
I visually checked the caps in the PSU; they are 1000uf Rubycon's (I don't recall the voltage rating). I don't have an ESR meter (yet) and my capacitance meter only goes up to 20 uf. Replacing the caps did cross my mind, but I first wanted to verify the problem wasn't occurring on the logic board.
NOW things are getting even screwier. As an aside, I've been working with electronics for more than 40 years. When I got started radios had tubes! I prefer 'broken' equipment to remain broken until I replace the defective part. As one of my friends said "Equipment that fixes itself will break itself, usually at the most inconvenient time possible".
After replacing the fuse, the shield over the PSU and logic board was replaced and the monitor hooked to a computer running Windows XP. As noted, it failed after half an hour (this happened twice, the second after it was unplugged for more than 12 hours). The test with the replacement power supply was done with the shield off. To verify it was the original power supply I hooked that back up (left the shield off) and let it run for a couple of hours. No problems!! I put the shield back on and again it ran for several hours without problems. On the hottest day of the year. The only variables are the additional run time and the computer it was hooked to.
It IS a bear to get the back off the monitor. I would prefer to get it fixed for SURE before putting the back on again. I hope to have this as my main monitor. Am I right to assume that replacing the two caps in the PSU would be a reasonable precaution?
Thanks,
PlainBill
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