First of all, thank you very much Pr0f and Tobias for your important suggestions.
Unfortunately I have no access to oscilloscopes, so for the moment I can not test the trimming capacitor. Regarding the expansion port, the pins look perfect.
tofro wrote:The start-up and memory test looks severely slowed down to me.
Yes, I confirm. The few times it occurs, the startup is extremely slow.
tofro wrote:DTACK is being generated by the 8301.
Even if it warms up somewhat, when installed in other functional machines it works apparently perfectly and remains almost cool. We can say the problem should come from elsewhere.
tofro wrote:CPU busy with handling spurious interrupts from various sources. If a thorough visual inspection of the board for possible shorts to the INT line
Could someone explain where exactly should I look for the INT line please?