Technical Design Labs SMB S-100 Board TDL Altair IMSAI SOL-20 TESTED/WORKING For Sale
Technical Design Labs SMB S-100 Board TDL Altair IMSAI SOL-20 TESTED/WORKING:
For sale is a Technical Design Labs (TDL) System Monitor Board (SMB). This board is an extremely versatile addition to any S-100 system and provides:
- 2K of ROM memory
- 2K of high speed static RAM memory
- Two serial ports with RS-232 or current loop
- Parallel I/O port
- Cassette interface
- Power-on jump circuitry
- Sense switches for monitor configuration
All tantalum capacitors were replaced as these boards are notorious for spectacular capacitor failures, especially when used in systems with big power supplies, like the IMSAI 8080. This board had very little wrong with it otherwise, there was a dead 74LS367 buffer, a missing 4047, and the power-on-jump wire had broken off. The flywire was replaced with a machine pin socket and 24 AWG jumper. There are factory modifications in place for the cassette interface, which we left installed.This board had plastic SEMI4804 static RAMs removed when we got it; however, one was dead so replaced all with matching side-brazed purple ceramic chips, from our inventory. These chips were hard to get when TDL was making the SMBs -- they actually had their own modification board which allows the use of 2114-type SRAMs to make up for short supply. We've designed our own equivalent, the GW-SMBRAM-2, which will be included in this sale, just in case the SEMI4804 RAMs ever fail. The GW-SMBRAM-2 shown is installed in a different TDL SMB.
The mask ROM installed in this SMB contains the TDL Zapple ROM monitor, version 1.1R. This versatile monitor does require a Z80 for operation. If your system uses an 8080 or 8085, we can modify the TDL SMB at no additional cost to accept a 2716-type EPROM and provide a copy of the TDL Apple monitor, which is 8080 compatible and follows the same basic syntax and command structure. We also have our own GWMON-80 SM available.
Schematics and manuals for this board are freely available on the Internet; however, due to external link policies, we cannot include links to them in this listing.
We have reproduction TDL Interface 1 and Interface 2 boards available for an additional cost, to be added to your total. If you would like one of these reproduction boards, please contact us before buying!