Reply 40 of 86, by mkarcher
biessea wrote on 2022-09-06, 20:07:Anyway in the inage you ask me yo measure pin 11 on u10 to pin 15 on simm sockets. (not pin 10 to pin 15). Pin 10 on the chip u10 is GROUND.
Probably you made a little mistake on the scheme you gave me before.
Yes, I'm sorry, I was off by one. The correct pin numbers would have been 11 to 18, not 10 to 17.
biessea wrote on 2022-09-06, 20:07:Anyway measurement are successful, I read about 33ohm (only in the pin 4 I can read about 34ohm but I think is correct so.)
Anything between 32 and 38 is acceptable, so the traces are fine.
biessea wrote on 2022-09-06, 20:07:The strange thing is that I can confirm measurement only in the first FOUR Simm socket near the resistances, the four socket upper give me 0.0.
Is four simm socket gone?
Doesn't have to be so. The chip named U10 is used as amplifier to send the address signal to the SIMMs. Possibly the upper four sockets use a different amplifier. Consider that a single SIMM might have 9 chips, all connected to the address lines. To operate four SIMMs, you thus need to drive the address signal into 36 chips. That's a lot of (electrical) work to do. It makes a lot of sense to use two amplifier chips, to distribute the load when 72 chips are installed (36 in bank 0 and 36 in bank 1). I don't think you have to check address traces for the second bank. I told you to test the address traces for bank 0, because U10 is so close to the battery, so traces connected to it might have taken damage.