Sunday, June 21, 2015

A little puttering on Father's Day before the family assembles


I moved the console printer into its final position - although I have a bit of cable to rethread into the 1131 - the cable for the 1053 is l-o-n-g compared to the distance when the printer is in place. About four or five spare feet have to be stuffed down and tied into place.


Found a bias resistor for the final power transistor for -5V that was damaged and had increased from its nominal 56 ohms (2%) to 2500+ ohms. I don't see how this could cause the +5V circuit to jump to over 8 volts, but it certainly could yield the low voltage for the -5V side. I will replace it when I return. Still looking for a cause for the problem with the +5 supply.


I found something I had bought more than a decade ago but never got around to testing or using. It is a US Navy workstation, I think it was made by Pace, that includes a vacuum pump, twin modulated AC power plugs for soldering irons, a Pace 'dual path' desoldering iron that fits the unit, plus mechanical drive motor and some other near-welding capability. I cleaned out the tip and verified the vacuum works well.

This will help a lot with all those pesky tantalum capacitors I want to swap out - the process of wicking off solder to open up the holes on the PCB was the tedious part. Now, I can take them off and use this desoldering unit to prep them for the replacement easily. Sometimes it pays to clean up back rooms a bit.

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