ASR 33 Teletype and a New 4k Core

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This is a bit overdue of an update, but...

We received a package in the mail from a collector.
They donated a 4k core and a M216 Flip Chip. We were borrowing one of Warrens extra cores before. We needed the M216 for the TC12-F option which allows us to read DECtapes as well as LINCtapes!


 
The 4k core was mostly working. Warrens Tune program said there was a bad row and column. Using a multimeter I tested all the diodes on the core. All of them seemed fine. One was a little flakey so we checked them again. Pushing on the diode caused it to snap in half. This was one of our problem diodes. The other one was a bit harder to find. We narrowed it down to a section of 8 and then used a power supply with current limited to 300mA to test it a bit more. The diodes normally would draw just around 1V. One of them was taking about 1.5V. I pushed on it a little and it cracked. This was the other problem diode. Both diodes were replaced and then I put the core in to test it. The memory checkerboard tests and Tune all said it was good, so I didn't bother retuning the core (I figured I'd leave well enough alone after what happened last time).
Below are pictures of the replaced diodes.



An anonymous donor gave us an ASR 33 Teletype, a second, partial, ASR 33 for parts, and quite a few rolls of new old stock paper tape. The Teletypes need some work, but are definitely fixable. I will be recording progress on them here too.  One of them has a ComData Corporation modem installed in it. I have not found a lot of information about it as of now. I will keep searching. 


We will be ordering supplies and some parts soon. Mainly grease, oil, and more rubbing alcohol. First thing will be to disassemble the Teletype and clean it.  




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