[M100] Model 102 issues

[Patrick Bureau]

So I have  model 102, that seems to be alive with a “black screen” Yes I checked the contrast button-wheel I did the break-reset method to no avail I checked voltages on VDD = 4.98,p Vb = 4.95e VEE = -4.99 I replaced the NICAD battery with a new one, I tested with no power applied, pin 28 I get 3.55v on all ram chips I tested with ac or battery power on, pin 40 of the CPU, I get 4.95v I checked for corrosion everywhere none was found under the battery tray. X1 clock is at 32.7680, X2 Clock is 4.9125 Pin 5 (reset) on M18 uPD1990AC is High. (4.98v)     Manual says to test T21, which I can identify next to the t22 on the schematics but  on the motherboard on either side it is not possible to find it, anyone have better eyes than I do that knows where its located?   Or it you have other suggestions I would love them   Someone suggested I test A0-A14 and D0-D7 on Rom and Ram, and found A0, A1 and A2 on ROM and RAM are being stuck High,  the rest A3-A14 and D0-D7 had traffic on them both on Rom and RAM I am trying to track it down as you read this email   Patrick B. (TTR)     Sent from Mail for Windows