I used to think that an oletimer was just lazy by telling me to check every IBM relay. He would say pull them out,blow them out and look at them. He would not even trace the schematics. He also liked to say the female plug contacts could be loose, so squeeze them tight before you plug each one of the relays back in. Any time there was an issue that was not obviously a mechanical problem this was his solution. The crazy thing was once he was called in,the same problem never happened again. And it was never a parts charge. Just labor.

Now we have the yellow jacket relays, in every unit that has not been modded.