more in the sorcerer saga.
a couple of months ago i was switching from serial to parallel flipper coils and somehow i borked the board. not sure how, but immediately after the re-wire that board booted into error code 7 again

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rather than mess around more with it i decided to just buy a working replacement board, so did that off of ebay. put that new board in yesterday, and it boots into error code 1.

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the guy i bought the board from had replaced the factory RAM with zeropower RAM, which seemed kind of nice at the time. but after poking around, i haven't seen anybody else do this on a system 9. i'm wondering if there would be a problem with that? i've seen it mentioned on a number of system 11s, but no system 9s.
anyway, i'm starting to follow the system 9 troubleshooting guide.
pressing the sound diagnostic switch produces proper sounds. pressing the CPU diagnostic switch causes the LED to flash to "0" then back to 1.
all the DC power levels look OK (+4.84 on the +5V input, +12.84 on the +12V input, +4.76 at Vcc of U11 and U17, etc.).
but i'm getting AC power levels that don't seem to make sense to me. i tested on J17 and seemed to get crazy-high values (+10V AC on the +5V input and +27V AC on the +12V input). so i went back to the power board, and if i test across test points 2 and 3 i get almost 100V AC?! that doesn't seem right. i did it with 3 voltmeters just to be sure (my fluke, another (cheaper) digital one, and my trusty old analog micronta) and read the same with all of them. am i measuring this wrong somehow? i haven't changed the power supply at all, and i know it worked with the original board previously, so this seems very odd.
thanks in advance for any guidance.