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I just realized today that the only copy I've ever seen of the ROMs from the Altair 88-RBM board have at least one modification versus the original ROMs. Does anyone still have this board that could dump the ROMs for me? I want to see what other differences - if any - there may be. The...

I imagine I've re-invented the wheel, but I created a utility to convert Intel hex files to .ent files for the Sol-20. The utility writes each line with just a CR at the end (no LF) so you can transmit .ent files to the Sol-20 at 9600 baud using a 100ms delay per line setting in your terminal...

Does anyone happen to have a TLF4C60801M flyback transformer for a Panasonic 9” monitor? Or know an acceptable substitute? This is for a Panasonic WV-BM900 monitor. I’ve got a hit from Sears, but that’s about it. Nothing on eBay presently. Mike D

Since the Altair Cassette Interface is difficult to find - and expensive when you do - I've recently demonstrated a way to make a drop-in replacement using more readily available and less expensive hardware. See Mike D

I have created a version of CP/M 2.2 for the Altair that does not require a disk controller. Instead, disk transfers are done through the second port on an 88-2SIO serial interface board and disk images are served from a PC. The server on the PC is the same server program that works with the...

The Shugart 800/801 drives (and the 8” media) have proven time be amazing reliable even after 45+ years. Even if not working, the drives are typically not hard to restore to working condition. There is one exception however - the small head pad carrier that snaps into the hole in the head pad...

I’m trying to identify the board (and the company that made it) in the pictures you’ll find at the link below. It is an 8K PROM board with auto-jump using PHANTOM to disable RAM. Any hints would be appreciated. https://deramp.com/downloads/vector_graphic/hardware/Vector%201%20Pictures/ Mike

When MITS introduced their Minidisk system, they clearly had plans for its use on both the 8800 and the 680. See: https://deramp.com/downloads/mfe_archive/010-S100%20Computers%20and%20Boards/00-MITS/30-Disk%20Storage%20Devices/22-88-MDS%20-%20680-MDS%20Minidisk%20System/88-MDS-1.jpg One...

Firmware version 1.7 for the Altair FDC+ adds a new drive type which duplicates operation of the iCOM/Pertec/Altair FD3712 drive cabinet. This drive cabinet/controller and its S-100 interface board implement the 8in SSSD IBM-3740 soft-sector format that was very common in the 1970's. The FD3712...

I have posted version 1.5 of the FDC+ firmware at the link below. The update affects only drive type 4, "Soft 5.25 inch as 8 inch". Primarily, the update adds support for disk drives that suppress index pulses while seeking. The newer the drive is, the more likely it is to suppress index pulses...

I’ve recently learned that as of November 2020, YouTube has asserted its right to insert ads into any videos they want - even if the creator (e.g., me) has specifically not monetized the videos to ensure viewers do not have to endure ads. Though there is now nothing I can do to eliminate these...

MITS/Pertec/iCOM FD3712, FD3812, FD360 owners: A few of us have been actively restoring this hardware and original software lately, and if you own any of this equipment, now would be a great time to dig it out and get your system running again while this is all fresh in our minds. Comment here...

I've noticed a lot of Sol-20 discussions in this forum recently. I've posted a good collection of original Sol-20 software on eBay some of you may be interested in. Search for "Sol-20 software". If this post is a no-no, feel free to take it down. Mike

Now that I have my SWTPC 6800 loading and saving programs with paper tape, cassette, and floppy disk (using the Percom LFD-400 controller and their MiniDOS and MPX ”operating systems”), the next logical step is getting FLEX up and running. Unfortunately, I only have the Percom floppy controller...

I’m restoring a SWTPC 6800 that includes the Percom LFD-400 floppy controller. This controller goes on the SS-50 bus instead of the SS-30 bus where the SWTPC controllers installed. The standard Percom MiniDOS PROM is installed, and the other two PROM sockets have a third party extension called...

Looking for a favor from Poly-8813 owners. Take a look at your CPU board, video board, and RAM boards and see if any of them have a wire as part of a mod that is tacked onto bus pin 16. The CPU board actually has a very short trace and feed-thru attached to pin 16, so look for a wire on the...

I'm laying out a small PCB to adapt the pinout of the DIP-16 socket used on the OP-80A paper tape reader to the DIP-14 socket used on the Solid State Music IO4 board. This allows connection of the OP-80A to an SSM-IO4 with straight-through ribbon cables (e.g., DIP-16 header to DIP-16 header -->...

I noticed several of the Solid State Music (SSM) PB1 EPROM Programmer boards sold on eBay recently. This prompted me to restore a PB1 I've had sitting around for a year or two. As part of the restoration, I ported Martin Eberhard's programming software for the Cromemco Bytesaver board to work...

I’m trying to figure out why later model 5.25” floppy drives - and most all 3.5” drives - added a jumper option to disable the output of index pulses during seek operations. I’m assuming it had something to do with the uPD765 controller IC that was used in early PC’s? Conversely, I frequently...

Since I don't want to "spam" everyone who has an FDC+ with an email, I figured I'd post information about this update on a few forums. The Altair FDC+ can serve disk content in real time from a PC using a high-speed serial port. This server has been updated to version 1.2. The new version...