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    Replacing the power supply in a Commodore PET 8032

    Picked up a CBM 8032 with a bad transformer a few years back. Posted about how to fix here http://www.vcfed.org/forum/showthread.php?65594-Converting-CBM-8032-PET-to-switching-power-supplies and finally got around to cleaning up the wiring and permanently mounting the parts. Here's the parts...
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    Recreating the Ferguson Big Board

    As part of a recent estate sale, my son and I ended up with two Big Boards, one built, and the other almost completely bare. Stripped the bare one down, took a couple of scans on a large format flatbed and started doodling in Sprint Layout. Doesn't look to bad to replicate if anyone is...
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    At VCF Midwest, dragged along some SBC6120 RBC full kits and FD50to34 Adapters

    Everything you need to build one, including the HD1-6120 chip and preprogrammed ROM's and GAL's. https://www.retrobrewcomputers.org/doku.php?id=boards:sbc:sbc6120-rbc-edition:start The ultimate Adventure game platform. $120 Also have some of NF6X's excellent 50 to 34 pin adapters (8 inch...
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    Converting CBM 8032 PET to switching power supplies

    Picked up a 8032 with bad transformer a while back, my son posted about it here. http://www.vcfed.org/forum/showthread.php?55630-Commodore-CBM-8032-Transformer-Problem&highlight=8032 Primary winding is open circuit, didn't see a thermal fuse anywhere. Bottom line is fixing the transformer...
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    Troubleshooting a Kaypro II power supply

    Picked this up from a neighbor awhile back, didn't power on at the time and the 12V line showed 0V under load, no load it showed almost 12V. Unplugged everything except for the logic and video boards, did a quick check on the boards and didn't find anything pulling the 12V line down, so just...
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    Zenith Z-90 repair log and schematic request

    My son recently acquired a Z-90 that would start-up, but only displays a cursor, no H: prompt. Seems like the CPU board is not starting. A quick tear down and right away here's a problem, blown tantalum cap and lifted traces all the way back to the power input on the +12V area of the CPU...
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    Model 4 Screen Brightness Issue

    Once the CRT on my Model 4 warms up, this is what my screen looks like, even at minimum brightness. The front brightness 500K pot tests OK, and it appears minimum brightness happens at the zero ohm end of the scale. Sprayed it with contact cleaner and even jumped the contacts to force zero...
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    Issue with FreHD Boot ROM in Model 4 Student Station

    I've got a Model 4 Student Station (Model 26-1059) that's a diskless 64KB machine. It has an 8048364 in U68, so I'm using the Gen 2 ROM image from Ian's page. http://ianmav.customer.netspace.net.au/trs80/downloads.htm Without the FreHD connected, I'm getting garbage screens on boot or...
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    Success creating new Model II disks with ImageDisk 1.18 and an FDADAP adapter

    Just wanted to share my experience with this. Things went better than expected and my son now have a number of new disks to play with in the Model II. I have the later rev drive controller card, so I simply unplugged the 50 pin connector from the TRS-80 card, and plugged in into the FDADAP. I...
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    New Model II Owner, couple of questions

    Picked up a well worn example from the original owner (tax preparation) for $100. Came with the unit, expansion chassis with one drive, and about ten disks (including a VisiCalc original). After cleaning out all the mice nests and re-seating of the cards, got it to turn on (yeah!). Next had...
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    Greeting from Minnesota

    My 13 year old son has decided vintage computers are cool after dragging my old TRS-80 Model I, TI-99/4A, Apple IIc, and Mac SE out of storage. Now through the magic of Craigslist we've added a couple of Commodore 64's, a Commodore 128, more Apple II's, more vintage Macs, a Kaypro 2, and the...
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