Re: Tek 7854 intermittent issues
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The digital board supply is only accessible if you remove all the logic boards - it hides away at the front of the 'scope to the left (as viewed from the front) of the logic boards.
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You can't get at that board while the scope is running, so you have look at the schematics and board layouts to find places to check the -12V and +/-5V that it supplies to the logic boards. Refer to pp 2-124 and 2-125 for a description of that supply and Schematic <38> for the A7 Auxiliary regulator board. You really need extenders to work on this beast - Gerber files available - sorry I have NO SPARE edge connectors. -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Nick Corvid Sent: 05 September 2020 06:36 To: [email protected] Subject: Re: [TekScopes] Tek 7854 intermittent issues Alright I've checked all the power supply test points I knew the location of (A12,A22,A17) Except I didn't get that digital supply David mentioned, which I'm not sure where the test points are, how to reach them, or what the specs are for that. Of the stuff I checked though everything came out relatively normal from what I could measure with my less than great instruments, well all but one thing, TP126 for the +108 volts that read 108.5 volts which is barely in spec but had some funky ripple pictured here on my auxiliary scope: /g/TekScopes/photo/252782/0?p=Created,,,20,2,0,0 . That was the only thing I saw that was out of the ordinary so far. |
David C. Partridge