I had a failure (R30 blew and I lost a ram on the main PCB) due to a bad connector. Since I was ordering parts anyway, I ordered an A/R II cap kit from Bob Roberts and put it on. I also did the sense mod, because I know that I'm not going to be able to replace the bad connector right away, and the sense mod will keep my A/R II board from blowing up for the moment.
Now, I just got time to put it back in and have a go. I put the A/R II back into the system, and I did NOT connect the main PCB (it's still on the shelf). I powered up (no smoke!) and started probing the test points. 22 reads a little high, +5 is at 4.97, +12 looks OK, but the -5 is at -15 volts!
Obviously this isn't right - does anyone have any idea where I may have screwed something up? I'm going to take it back out tomorrow and re-check all the capacitor values and the transistor part numbers to make sure that I didn't put one in the wrong place. If that doesn't pan out, I'll have to start back-tracking down the -5 volt supply.
Any hints of things to look for would be greatly appreciated.
Now, I just got time to put it back in and have a go. I put the A/R II back into the system, and I did NOT connect the main PCB (it's still on the shelf). I powered up (no smoke!) and started probing the test points. 22 reads a little high, +5 is at 4.97, +12 looks OK, but the -5 is at -15 volts!
Obviously this isn't right - does anyone have any idea where I may have screwed something up? I'm going to take it back out tomorrow and re-check all the capacitor values and the transistor part numbers to make sure that I didn't put one in the wrong place. If that doesn't pan out, I'll have to start back-tracking down the -5 volt supply.
Any hints of things to look for would be greatly appreciated.
