Hi, new member.
Trying to help a friend fixing a 11B from a Whirlwind, but the board is a basket case, had some alkaline damage, so somebody rebuilt the reset section and did a very bad job, it does however work.
Main problem with the board is on power up, diagnostic flashes 60 times, then blanking 10, and repeat, no difference if U25 or U26 is removed, however sometimes you can make the board boot by touching an ic with a finger, and when it first runs it works perfectly.
Board had all the PIA (6821) replaced, new sockets, new ram, new eproms, problem was the same before all this work.
When using Leons test rom, everything seems to be in order.
Trying to help a friend fixing a 11B from a Whirlwind, but the board is a basket case, had some alkaline damage, so somebody rebuilt the reset section and did a very bad job, it does however work.
Main problem with the board is on power up, diagnostic flashes 60 times, then blanking 10, and repeat, no difference if U25 or U26 is removed, however sometimes you can make the board boot by touching an ic with a finger, and when it first runs it works perfectly.
Board had all the PIA (6821) replaced, new sockets, new ram, new eproms, problem was the same before all this work.
When using Leons test rom, everything seems to be in order.