tb lilley
Member
I've just repaired a spare AR2 which was giving me a too high reading on the +5VDC. All now appears to be well, and I'm now getting a nice steady reading of the +5 at the appropriate test point on the AR2.
Hooked up to the PCB (Missile Command) and the +5 has gone AWOL, but still reads fine on the AR board.
I don't think I've got a continuity problem as when I put my other working AR2 back in, the +5 reappears on the MC PCB.
So, I'm thinking I have a problem with connector J7 on the AR2, which should output the +5. As a first step I want to probe J7 to see whether the +5 is present and correct.
Question: which pins on J7 should I probe? The schem shows pins 5&6 as both having +5VDC REG, so is it simply a case of checking these? Is so, which pin takes black/red leads off the DMM. Excuse my ignorance, but my experience on DC voltages to date has been checking for voltages at a clearly defined test lug and ground point.
Hooked up to the PCB (Missile Command) and the +5 has gone AWOL, but still reads fine on the AR board.
I don't think I've got a continuity problem as when I put my other working AR2 back in, the +5 reappears on the MC PCB.
So, I'm thinking I have a problem with connector J7 on the AR2, which should output the +5. As a first step I want to probe J7 to see whether the +5 is present and correct.
Question: which pins on J7 should I probe? The schem shows pins 5&6 as both having +5VDC REG, so is it simply a case of checking these? Is so, which pin takes black/red leads off the DMM. Excuse my ignorance, but my experience on DC voltages to date has been checking for voltages at a clearly defined test lug and ground point.