Philips PM5544 electronic testcard

[ppppenguin]

I found another subtle fault that caused the top and bottom castellations to be unequal height. One input of a 7402 quad NOR gate was stuck at zero. Managed to replace the wrong chip, an adjacent 7402. No excuse except sheer stupidity. Although they weren't on my stock list I found a few 74LS02 in the drawer. A good substitute.

Makes me wonder if there are any more subtle faults like this.