Altair 680B Reproduction

Creating a Reproduction Altair 680

With no one currently making reproductions of the Altair 680 boards, we have decided to add the Altair 680B and Altair 680 Turnkey boards to our product line. Creating the reproduction of the Altair 680 was difficult since few units come up for sale, and those that do are priced very high. In addition Altair 680 owners weren't interested in loaning their rare and valuable computers so the computer could be disassembled, measured, scanned, and used for testing the reproduction boards. Our reproduction boards have been tested in real Altair cabinets and can be used as replacements. I will thank Mike Douglas for his efforts in providing accurate measurements of Altair 680 boards and for testing the reproduction boards in his Altair 680 computer. You can find Mike Douglas's website here - https://deramp.com/ - his website has information on many brands of vintage computers.

Reproduction of Main Board

The reproduction of the main board was created from photographs of bare boards found on the internet. The photographs were taken from angles so the images needed extensive processing before they could be used to create artwork. Even the corrected photos had shifts of up to 0.15" in parts of the image. After obtaining dimensions and mounting hole locations from a real board we placed the pads for the IC's using measurements and some guess work to locate the parts as accurately as we could. We then routed the board based on the photographs to produce a layout of the main board. A few minor changes that were made were adding extra pads for the crystals and a few extra pads for some of the capacitors.

Front Panel Board

The front panel board created additional challenges since the location of the mounting holes has to be accurate if the board was to be interchangeable with the original. A dimensionally accurate dress panel was created to aid in this task. The dress panel was tested on an original Altair for fit before serving duty in creating a reproduction front panel PCB. We had difficulty in getting the LEDs and switches to line up with the original. It was assumed when laying out the board the dimensions would be in some multiples of 0.05" or in multiples of 1/16". It was later determined some of the spacing is metric and some of it is English on the Altair front panel. The PCB layout of the front panel PCB was also based on photographs of an original PCB found on the internet. Changes made to the PCB include the modification listed in the front panel assembly manual. Modification of an assembled reproduction front panel PCB is no longer necessary.

Reproduction Cabinet

With the main board and front panel having been reproduced, a cabinet is needed. The Altair 680 case was made by Optima. While it might be possible to have Optima custom make more cases the cost and quantity required would likely be prohibitive. A cheaper solution is needed. One lower cost solution is to use a 3D printed case. While not exactly inexpensive or even easy to print, a 3D printed case can provide for a more affordable replacement of the original. Some changes are required for 3D printing. The case has to be thicker; this precludes an exact match of the original. Since this cabinet is only going to resemble the Altair case other changes were made. Support pads were printed to support the main board. The main board in the Altair cabinet was poorly supported. The case was made slightly deeper. In the Altair case the transformer covered the RAM and was very close to the main board. The reproduction case provides more clearance. The goal for the reproduction case was to resemble the original and allow mounting of an original Altair board set.

Unavailable RAM Board

When this project started we were only going to reproduce the main board, front panel and a case. At the time there was an aftermarket RAM board. That board has been out of stock for many months now. Without extra memory, the Altair reproduction would be very limited in use. There is only 1K of memory on the main board. This created the need to make an additional board if the reproduction system was to do anything useful. It's also very hard to test the reproduction board set with so little memory. With the memory board now being unavailable it was clear I would need to make at least one memory board for myself so I could comprehensibly test the reproduction. I decided if I'm going to make a board, I might as well create a really good board. I decided to put RAM, EPROM, RTC, two IDE ports, and include the parallel and serial ports from the MITS UIO board. Introducing the new board . . . . . . .

New MIO Board (Memory I/O)

Back when this project was started we did not consider reproducing the Altair 16K memory or the UIO board. Using a much newer RAM chip we can provide 60K of RAM using only one chip. This leaves the board almost empty. To fill the extra space we added up to 32K of EPROM, a real time clock (MC146818), two IDE controller ports, and still had enough space to include the functions of the Altair UIO board. The UIO board has two MC6821 PIA chips and one MC6850 serial chip. We kept the same 24 pin socket for the PIA as used on the UIO board. The serial port is restricted to RS232 on the MIO. The address of the MC6821 and MC6850 can be set on 16 byte boundaries just like the MITS UIO board. The MIO board ships with a modified SWTBUG monitor. The modified SWTBUG can start the Altair monitor program if you wish. The MIO can boot FLEX from the IDE port, FLEX using the serial port, or FLEX using the Corsham SD Card system.

Turnkey Front Panel

After ending up making all of these boards we decided to do the Altair 680 turnkey front panel. While the front panel with LEDs and switches certainly looks impressive, it is very expensive and not very useful. The cost of switches makes up most of the cost of the Altair front panel. Dropping the front panel makes for a less expensive system. The turnkey PCB panel was created from the MITS turnkey front panel schematic. Not having photographs of a turnkey front panel circuit board, the board layout was created from scratch and will not match the original. The dress panel was styled to resemble a photo of a Turnkey Altair found on the internet. While the entire reproduction PCB and dress panel can replace a original Turnkey board and dress panel, the original PCB and dress panel are not interchangeable with the reproduction parts.

More information about each board can be found on their product pages.

See the Reproduction in Operation

This video was made by Mike Douglas showing the Reproduction in operation.

YouTube Video showing the Reproduction Altair 680

Ordering and How Long Will it Take

I generally don't stock completed computers or assembled boards. I build them after an order is received. Bare boards, however, will ship quickly. At product launch I expect to have 5 to 6 cabinets and a few board sets ready to ship or install in cabinets for a completed system. After those boards/systems are sold, the lead time will depend on how many orders are received. If only a few want a board or a system there will not be much of a wait. If 20 people want a system, it will take a while It is unlikely more than two assembled systems per week can ship. At the most, production can't exceed three systems per week because of the time it takes to produce the cabinet. Orders for assembled boards not needing a cabinet can be filled somewhat quicker.

If you wish to place an order send an email to SALES@PERIPHERALTECH.COM with what you want and your address. I will get back to you with the total cost of your order including shipping and give you an estimated ship date and payment information.