More Power Supply Testing and Front Panel Testing

By Anonymous -
More testing was done on the power supply. I powered it up, and it worked fine. All of the output voltages were within the allowable tolerance. I powered it up a second time after letting it sit again (still using the variac), it worked for a bit and then the newly replaced shunt resistor started to glow bright red, and I quickly powered it off. 

After letting it cool down it was powered back on. It worked fine. I powered it off, then back on again but this time straight from the wall and not the variac. It worked fine. This process was repeated a couple times and I could not get the resistor to get hot again. 

I will keep poking around the wiring until I figure something out. 

I learned on RICM's PDP-8/I restoration blog that by reversing the +15V and ground connections on the back of the front panel all the lights will turn on. It drew about 1.5 to 2 Amps of current, but powered on and looked very pretty.





Almost all of them powered up nicely, but we likely will replace all of them just to avoid more burning out.

The switches were cleaned up too in an attempt to remove the 40 year old dirt and grime. 

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