A bit of an update

I replaced all the female pins on the interconnector board

There are two main issues at this point in time.

1. No displays
2. Booting problems - i think...strange diagnostic 7 segment display on the CPU

1st the boot issues

About 1/2 the time, it boots seemingly OK (ie: flashes 0, then stays 0)
Other times it is a constant 0 (no flash), and sometimes error 2 comes up (bad IC13 RAM), once error 8 came up!!

Is there a way to test the RAM on the board (i have a logic probe but no idea what to do with it!!)? or should i trust the self test and just replace it?

Some of the other IC's are pretty dodgy looking (a bit of corrosion etc) but when i put the DMM on continuity, they were all getting a signal from the leg to where the socket is soldered on the PCB.


2nd the display issue

There is no power (a couple of mV) at the blanking signal wire (1J3 pin4) or test point 4 or interconnector pin 37.  I put +5V to TP4 and the displays started flashing some funky numbers on and off, so i think i can safely assume the displays are OK.  Twice when i powered it on a single 0 on one of the displays flashed up briefly.

Is this issue a result of the booting problems and the blanking signal is not allowing the displays to work, or am i completely on the wrong track?

Suggestions??