Re: 475 questions


ciclista41@...
 

Hi Albert,

Thanks for replying! I only used an analog multimeter to take the readings, and I verified them with another analog, so am confident in the values I got. However, the value of resistance readings has been called into question, anyway.

I put together a voltage-limiter (150W incandescent bulb in series with the hot lead of my wall receptacle, which greatly increased my confidence that turning the scope on would not do further damage.
So far, so good! With the scope turned on, the filament glows dimly, so I probably should run a 200W bulb, but I don't have one handy. Knowing that the scope would run without smoke or pops, I took readings with the voltage limiter and then plugged directly into the wall, with the latter readings in parentheses. Yes, a larger bulb is in order!

Checking voltages at the same test points that I got the resistance readings from, I got:

110 = 87 (91) 83%

50 = 37.5 (40) 80%

15 = 10 (10) 67%

5 = 3.5 (3.8) 76%

-15 = -14.2 (14.5) 97%

-8 = -5.7 (6) 80%

UNREG 50 = 40 (47) 94%

105 = 7.5 (9.5) 9%

The scale intensity seems to work fine, but I get no trace at all. I put my probe in Ch. 1 and put the negative to chassis ground and positive to the calibrator, but still got nothing. Pushing the beam finder button didn't help, either. Same story with Ch. 2.
All indicator lamps on the front seem to be working fine. Fan works fine. Nothing seems to be getting hot.

Time to start desoldering, I guess.

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