Hi everybody,
This little post to share my last experience with an old SC501 TM500 oscilloscope.
I haven¡¯t used it for 3 or 4 years and when I switched it on, no power and a nice smell of baked resistor.
It was like often a tantalum capacitor in short circuit (C514). I replaced it, changed the burned resistor (R512) and it worked again.
I just saw a strange problem: the trace was blur in horizontal. When I switched to XY, it displayed a little line of 2 mm wide instead a single dot.
I suspected first some ripple in the 65v supply, but it was shared with the vertical amp so, why in X mode only ???
After a closer exam of the schematic I thought that the only source may be the 1?F capacitor C420 or C412. I removed them and they presented a high ESR. I changed them with non polarized 1?F film capacitor and the plugin retrieve a nice and fine spot.
I profited to fully recalibrate it and it¡¯s now perfect !
May be this experience may help ¡
I have put a video of the fixed item with a FG507 on my YouTube Channel:
Cyrob: D¨¦mo des tiroirs Tektronix TM500 SC501 et FG507
Cyrob: D¨¦mo des tiroirs Tektronix TM500 SC501 et... Une petit d¨¦mo de mon SC501 r¨¦par¨¦. J'ai pass¨¦ mon samedi ¨¤ le r¨¦parer et le recalibrer. J'en ai profit¨¦ pour vous montrer le FG507, un tiroir TM500 assez r...
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Feel free to contact me if you have any question¡
(Sorry if my English is not perfect, I am French¡.)
