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  1. J

    512K memory upgrade for the Model I - its here!

    Haven't looked at my XLR8er for ages, so I pulled it out for a 'photo op'. It looks like this one uses a four-layer PCB that might be hard to copy.
  2. J

    Scuzzy SCSI

    In another discussion, I got the idea to add in a SCSI card and drive for my IBM PS/2 55SX. So, I found a card, cable, and drive - but now the configuration is making me think it is scuzzy, instead of SCSI. The card is an Adaptec AHA-1640. The .adf configuration file was fairly easy to find and...
  3. J

    IBM PS/2 Hard Drive Issues

    Sigh! My luck (or lack thereof) with SCSI cables continues. All the parts I ordered are here now and the attached shows somewhat of a mismatch between the connector on the board and the connector at the end of the cable. Both are 68 pins, but they sure don't mate. After looking at connectors...
  4. J

    RCA VP-616 membrane Keyboard

    Yep, it does have a CA3140 and that's what I used to trace those pins back to the connector. -12v is on pin 17, +12v is on pin 18, and data out is on pin 2 of the DB25. There are significant differences between this board and the schematic. All the chips have the 'CD' or 'CA' prefix (old RCA...
  5. J

    RCA VP-616 membrane Keyboard

    Does anyone have pinout information for the DB-25 connector on the back of these? The "manual" I found is pretty skimpy. It does say that it needs +5v and +/- 9-15v for the RS-232 connection, but not where to feed them on the connector. I believe they were produced in the early to mid 1980s...
  6. J

    WTB: PowerBASIC version 10 manual

    Anybody have a printed PowerBASIC version 10 manual they want to sell? I upgraded and while the help files are good, I still prefer dead tree format for reference. Exported the help file to PDF thinking to print it, but that generated about 1800 pages. <*> Jim
  7. J

    Tandy 1200 motherboard for sale (not mine)

    Saw this today on eBay and thought it might interest some of you: http://www.ebay.com/itm/Vintage-Tandy-1200-Mother-Board-1st-Gen-5-Slot-256K-PCBA-188381-001-/311451994903?hash=item4883fc4b17 Jim
  8. J

    How to trace/fix video RAM problems TRS-80 Model 1

    Z62! (Sounds like I should shout BINGO!) That was the bad chip on my Model I motherboard. Of course, once I had the Mod I apart on the bench, I couldn't find the 21L02 chips anywhere in the garage. So, after a quick trip to eBay, the chips arrived today. Using the piggyback method Frank...
  9. J

    Wanted: ancient BASIC Lab Notes book diskette

    I've picked up a couple copies of this book but have never been able to find the companion diskette or an image. It would be fun to play with some of the code, but not finding and fixing all the typos if I have to key it in. PC Magazine BASIC Lab Notes by Ethan Winer and Phil Cramer Published...
  10. J

    Highly Optimistic TRS-80 Mod I system eBay auction

    This one is for those TRS-80 collectors with way more money than sense: http://www.ebay.com/itm/Tandy-TRS-80-all-original-all-original-cables-Complete-system-/181456377768?&_trksid=p2056016.l4276 Or, maybe the seller is just a little, um, enthusiastic.
  11. J

    TeleVideo Trouble

    Yes, I saw that page - but the document is for a 55(L) and my 55B has a different arrangement as pictured in my attachment above. Teac probably had dozens of variations of their 48 tpi drives. It must have driven their tech document writers nuts. Here's a photo of the board on my 55B with the...
  12. J

    TeleVideo Trouble

    The 55BR strapping is highly abbreviated from the manual in the link - there isn't an HM jumper: I just have the DS0 and FG jumpers plugged. (Dunno what FG does, "Feels Good"?)
  13. J

    TeleVideo Trouble

    Found a TeleVideo TS-802 and keyboard on eBay recently that looked like a reasonable deal for less than $100 delivered. {Of course, I didn't know that the seller was going to wrap the computer in brown kraft paper, tape it up, slide it into a box with 4" of space all around, then mail it Postal...
  14. J

    Looking for ISA Video Card with Headland HT205 or G2 GC205 Video Chip

    Sam - Well, good news / bad news. I did finally find the video card with the Headland chip. Unfortunately, its a different chip - an HT208, not an HT205. Will this still work for you? The EPROM has a legend, "Copyright Zenith Data Systems", so it looks like it originally came out of a...
  15. J

    How to repair this TRS Mod I DDen adapter?

    The ad said this Mod I Expansion Interface had an extra "memory board" when I bought it. Turns out it was a Tandy double-density adapter that should have been mounted in the socket for the WD1771. Unfortunately, it popped free during shipping and apparently bounced around quite a bit. All the...
  16. J

    Anybody remember MRS-OS?

    Came across a couple 5.25" diskettes from long ago. One was labeled "MRS-OS w/our BIOS" (a 'big board' kind of machine) and the other just "MRS". Further digging produced nothing in the way of documentation. As I recall, MRS was Z80 based CP/M replacement system. But, that's about all I can...
  17. J

    Can this 5170 motherboard be saved?

    Ugh! Found this 5170 AT system in sort of rough shape and things got worse when I looked inside. The original lithium battery split open and leaked (hey, thanks Tadiran!) over a small portion of the motherboard around the keyboard connector. The system powers on, but won't POST or boot. It...
  18. J

    Looking for a PS/2 8556 SCSI mount

    Recently picked up an IBM 56 SX machine without a hard drive. I found a SCSI drive that works just dandy, but it had no mounting bracket. :( Anybody got one they'd like to part with? It looks like the hard drive mounts on a "sled" to the bottom of the drive cage. There are also rail-like...
  19. J

    Beeeep Bee-Beep

    My recently received 5150 with the big 'B' stamped on the back came with a CGA card. It was fun at first, but the ol' eyes flashed back to the mid-80's and protested that viewing text on a CGA display (even if it IS an IBM) is still cruel and unusual punishment. So, I picked up a WD Paradise...
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