![]() As R107 is still reading correct value then it's possible that it's marginally rated for the voltage across it. If you're in a high humidity climate (which I'm guessing you are) this contamination could easily be enough to cause flashovers you are seeing. The first thing I noticed about your photo of the board is that the area around R107 doesn't look too clean, there looks to be surface contamination and fine dust on the surface- fairly typical in high voltage areas and I would bet that there are the same contaminants on the body of the resistor itself. 5v square wave on this scope if I feed it in with a signal generator? Could it be a faulty fly-back transformer (causing the arcing) or something to do with the broken voltage adjuster? 5v config pin on the face panel? Ive tried to adjust it from the instructions in the service manual with no luck.I can get a. 5volt square wave when I connect my probe onto the. Another thing is that I cant configure a proper. Its associated with the focus but the focus seems OK? Ive checked all the voltages from the power supplies and there all OK although I haven't checked the 1900volt on the focus. The symptoms are the arcing across resistor R1017,this resistor is raised up on its pins from the PCB,I found it was pushed down so the pins were bent causing it to visibly arc? When I straightened the pins, the arc wasn't visible anymore but I can still hear it in the same general area? Actually the resistor is not 2 watts its 1 watt 22m ohms,it reads 7.20m ohms in circuit and 23m ohms out of circuit. That's basically what I'm asking, Why is it doing this? Then I might have some idea of how to fix it. I have the schematic for it but I cant work out why its arcing across the resistor? Could it be that the fly-back transformer has had the bomb? I have the parts list for this scope but nowhere to order them from? Where I live is fairly remote and the local repair shop cant be trusted to change the battery's in a TV remote.LOL Ive included some photos,one shows the big brown 2 watt resistor that has the arcing across it, next to the fly-back transformer. 5v calibration pin? and there's a spark that jumps across a 2 watt resistor in the power supply on start-up and intermittently after? I checked the scope out and found a broken (shattered) plastic voltage adjuster for 100v,120v,220v,230v,on the back next to the power plug.Ive got it set for 230v for here in Aussie land, with the fuse on the yellow 240v wire. 5v square wave when the probe was connected to the. Ive been trying to fix my Hung Chang brand, (Protek 6502 model) scope that I bought second hand (in good working condition)? After it was delivered in the post I noticed that it couldn't get a. ![]()
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December 2022
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