13-02-2020, 01:33 PM
I have a total of 6 of these monitors at present. Had a look at the only 2 other monitors that worked when initially switched on. One is excellent, not looked inside yet. The other worked well for a few minutes, then gave a bad smell and some smoke. Picture still present but poor contrast. Looking inside revealed an obvious culprit. C12, the smoothing cap for the +110V rail, looked lumpy and iffy. The 110V rail itself was down at about 25V. Probably being held up by the main HT via some route that's not immediately obvious. The 110V rail is rectified off the LOPT, as are several other supplies.
As I was removing the duff cap I saw that R10 (22R) a surge limiter in series with the 110V rectifier was badly burnt. It was open circuit. The rectifier itself tested OK. The cure was obvious and that monitor now works again. The height control preset pot is very intermittent, probably due to damp storage. Probably need to replace. Need to look at all the pots.
I might review the other 3, all in various stages of non-workingness.
As I was removing the duff cap I saw that R10 (22R) a surge limiter in series with the 110V rectifier was badly burnt. It was open circuit. The rectifier itself tested OK. The cure was obvious and that monitor now works again. The height control preset pot is very intermittent, probably due to damp storage. Probably need to replace. Need to look at all the pots.
I might review the other 3, all in various stages of non-workingness.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
