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Old 19th Oct 2020, 3:33 pm   #16
ColinTheAmpMan1's Avatar
Join Date: Jan 2012
Location: Wimbledon, London, UK.
Posts: 1,362
Default Re: Tektronix 7623A poser

Originally Posted by ColinTheAmpMan1 View Post
Of course, it is infinite. Probing around a bit at the earth/ground points, the pad that the negative end of C1198 is supposed to be soldered to doesn't have continuity to any other earth point (including C1193). It looks as though all of the other earth pads are connected together and to chassis. So perhaps a trace on the other side of the board has burnt out.

Is it possible that C1198 shorted, then took so much current (enough to blow F814) that it blew L1198 and then itself to lose all of its capacitance and become open circuit? Then the loss of continuity between the negative pad of C1198 and all other earth/grounds could be from burning-out the track?

A bit of a correction, here. This board is a tricky one to get meter probes to. The earthy ends of C1198 and C1193 are connected, but have no continuity to earth/chassis. Two other local capacitors do have their earthy ends connected and continuity to chassis; they are C1245 and C1250. It's looking more and more like a burnt-out track.

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