Re: 475 questions


ciclista41@...
 

Hi Albert,

Yes, I re-read them just after turning the scope off, before my last reply, and I re-read them just now. All three are shorted regardless of the polarity with which I measured them. So it's surprising to me that the board doesn't pop, get hot, or release magic smoke when I run it.

I was guessing I'd have lots of ripple with bad capacitors, but I really don't know if they're bad or how bad they are. Currently, no meter I have measures such high μF. Guess I'd better find one. Just a month or two ago, I was checking the start and run capacitors on my roof-mount air conditioner. We Arizona desert dwellers do not want the air conditioner to quit during our summers. That can be deadly if we don't move out temporarily until it can be fixed or fix it immediately. They're predicting 108°F for this coming Wednesday, so the season is just about here. Although all capacitors measured within spec, I still bought replacements to have on hand. The only one I could not check was the compressor start capacitor, because it is rated higher than my meter will go. Another reason to find a better meter.

I bought two non-working scopes at once, so although the 475 is not necessarily my first scope, neither do I have another scope that works. I'm tempted to buy a new digital scope, but I might wind up disappointed in one that I could justify the expense for. Maybe not. I haven't done enough research to take that plunge yet. And if I get this one working, I will find it even more difficult justifying such an expense.

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