Sunday, July 30, 2017

Found bad custom chip part in 7854 scope and replacement part is amazingly available

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TEKTRONIX 7854 REPAIR I can see that the Display board is generating the XYINH signal that should block the analog scope signals from be...
Saturday, July 29, 2017

Ups and downs with Alto demonstration, finished the Heath C-3 Condenser Checker restoration

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HEATHKIT C-3 TESTER RESTORATION The last of my replacement parts arrived today and I soldered everything together. The chain of higher wat...
Thursday, July 27, 2017

Fixed triple power supply from a flea market

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TRIPLE POWER SUPPLY REPAIR At a flea market, I came across a triple power supply for a very attractive price. When I brought it home, I no...
Wednesday, July 26, 2017

Restoration work on Heath C-3 and on a 1401's card reader

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HEATHKIT C-3 CONDENSER CHECKER RESTORATION Most of my replacement parts arrived, including the 1626 tube, which I soldered into place. I ...
Tuesday, July 25, 2017

Wrote demo disk cartridges, practiced VCF-W demo and continued archiving PARC cartridges

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XEROX ALTO RESTORATION PROJECT We met today to work on the demonstrations we will give at Vintage Computer Festival West in a few weeks. ...
Sunday, July 23, 2017

Failed part discovered in C-3 Condenser Checker, improvements made

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HEATHKIT C-3 CONDENSER CHECKER RESTORATION The main power is set by a voltage divider, with ground at the center node. There is a 47K re...

Fixing up an old Heath C-3 Condenser Tester

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HEATHKIT C-3 CONDENSER CHECKER RESTORATION I brought my C-3 over to test the capacitors we removed from the old Alto power supplies, but t...