05-06-2022, 11:39 PM
Hi Ernest,
I did think of that but all my RAM boards have tantalums and they check out at ~230nF. I swapped C21 from good board to bad and it's still failing. You're right though, this is probably RESET based but for a different reason. This is where my lack of formal electronics training lets me down. On the good board at pin 3 of the inverter I get ~4.8V but on the bad board pin 3 is receiving ~0.4V. I've also noticed that the good board has /KBRST at ~4.8V but the bad board it's only at ~2.8V. After lunch I'll pull the resistors to check them.
Cheers
Witchy
I did think of that but all my RAM boards have tantalums and they check out at ~230nF. I swapped C21 from good board to bad and it's still failing. You're right though, this is probably RESET based but for a different reason. This is where my lack of formal electronics training lets me down. On the good board at pin 3 of the inverter I get ~4.8V but on the bad board pin 3 is receiving ~0.4V. I've also noticed that the good board has /KBRST at ~4.8V but the bad board it's only at ~2.8V. After lunch I'll pull the resistors to check them.
Cheers
Witchy
--
Binary Dinosaurs, where RIFA capacitors come to die
www.binarydinosaurs.co.uk
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Binary Dinosaurs, where RIFA capacitors come to die
www.binarydinosaurs.co.uk
facebook.com/binarydinosaurs
@binarydinosaurs