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glitch
March 13th, 2018, 03:19 PM
Some of you have probably heard mumblings online about how someone's doing an IMSAI MPU-A reproduction. Behold:

http://i.imgur.com/HceJJCbh.jpg (https://imgur.com/HceJJCb)

Gary Kaufman had a blank IMSAI MPU-A scanned and did a prototype run of boards. This is the same scanning technique that we've used on the OSI reproduction boards and my SSM IO-2 reproduction. I tweaked the Gerber files for him and added info regarding the design's status as a reproduction. Gary will be selling production-run blank boards soonish at around $30-40 per board depending on final costs. The boards will be run with hard gold edge plating (the prototype above is HASL, of course). I'll be building up a few parts kits for these boards.

Intel 8216 bus buffers replaced with their Soviet clone counterpart:

http://i.imgur.com/jLrXlAah.jpg (https://imgur.com/jLrXlAa)

Running in my IMSAI:

http://i.imgur.com/ey1IixIh.jpg (https://imgur.com/ey1IixI)

You can see garbage from the Polymorphic VTI on the little monitor; it hasn't been initialized yet. I dropped in a ROM board with the Vector Graphic ROM monitor with VTI drivers:

http://i.imgur.com/RDKIoRJh.jpg (https://imgur.com/RDKIoRJ)

It lives! Full album here: https://imgur.com/a/tAepr

8008guy
March 21st, 2018, 01:03 PM
Neat!!!

gekaufman
March 21st, 2018, 01:43 PM
Neat!!!
Board are in production, and I'll offer them up in a few weeks.

I also have Altair 8080 CPU boards being fabricated.

Several folks including Glitch have been a huge help in making this possible.

- Gary

glitch
March 21st, 2018, 02:36 PM
There will be parts kits available for both, as well. Just got in an order of correct Thermalloy heat sinks!

jhalbrecht
March 22nd, 2018, 07:25 PM
Board are in production, and I'll offer them up in a few weeks.

I also have Altair 8080 CPU boards being fabricated.

Several folks including Glitch have been a huge help in making this possible.

- Gary

Did you do a prototype run of the Altair CPU too? If so has Glitch and/or others tested a prototype of the Altair CPU?

When orders are taken I'll commit to three (3) each of the Imsai and Altair CPU boards and parts kits for all.

- Jeff

gekaufman
March 22nd, 2018, 07:48 PM
I did a prototype run of the Altair CPU as well. Here's a picture of a board built up by Martin Eberhard.

- Gary
44554

8008guy
March 22nd, 2018, 08:03 PM
What are the prices for bare boards?

gekaufman
March 23rd, 2018, 01:07 AM
Just waiting to figure my final costs, but will be in the $30 - $40 each range for bare boards. About 1/2 the cost will be going to cover the purchase/borrowing of the bare boards, scanning and prototype production/shipping.

I should be ready to offer boards in about 2 weeks.

- Gary

glitch
March 23rd, 2018, 07:46 AM
The Altair CPU board has been corrected from "CPU BB" to "CPU BD" in the final production Gerbers :p

Super excited to have reproduction boards actually *available* to us hobbyists at a fair price. I believe Gary is running them full-spec with hard gold plating and all, so they should also be very *durable* reproductions. Drives me nuts to see more expensive boards with HASL or ENIG on an edge connector!

snuci
March 23rd, 2018, 07:51 AM
The Altair CPU board has been corrected from "CPU BB" to "CPU BD" in the final production Gerbers :p

I thought that was on purpose because they are so close :) It is an excellent reproduction.

8008guy
March 23rd, 2018, 07:56 AM
I would be interested in one of each.

Len

glitch
March 23rd, 2018, 08:11 AM
I thought that was on purpose because they are so close :) It is an excellent reproduction.

It says it's a reproduction on the back, with Gary's site's URL. They do look nearly identical to the originals from the front, especially the IMSAI board!

Mal
April 2nd, 2018, 06:59 PM
Well done Gary. This is excellent.

I'd like to register my interest for 2 x kits (including 2 x PCBs), when available.

Are you able to post a few notes documenting the steps taken (tools used etc) to get from a scan of the old board, to a clean set of Gerbers and drill file? I recently finished an unrelated reproduction project. It took several hundred hours to accurately measure the placement of tracks and vias, while redrawing the lot in KiCAD. I'd say I did it in about the least efficient way possible!

Malcolm.

glitch
April 3rd, 2018, 03:42 AM
You send the boards to Mile High Test/Gardien Services, pay the fee, and get Gerbers back. They'll digitize all of the layers you'd like (silkscreen, solder mask, etc.). A two-layer S-100 sized board costs around $250. The board has to be stripped of all components. They can do multilayer (4+ layer) boards, but the board is destroyed in the process. Well worth the cost IMO -- as you discovered, there's a *lot* of time in it, and I wouldn't be able to get nearly as much done if I were doing the conversion to Gerbers myself.

gekaufman
April 26th, 2018, 06:08 AM
IMSAI and Altair CPU Boards are now available, please see the posting in the marketplace for-sale section.

http://www.the-planet.org/gkaufman/S100/Altair/Repro_Front_s.jpg

http://www.vcfed.org/forum/forumdisplay.php?28-Vintage-Computer-Items-For-Sale-or-Trade

Dawsoca
June 6th, 2018, 01:21 PM
6/6/2018

SUBJECT- IMSAI 8080 PARTS LIST

If anyone has purchased one of Gary Kaufman's IMSAI 8080 reproduction boards and is in need of a parts list, I have enclosed one if it would be useful to anyone.

> Charles

45951
45952
45953

6/6/18

UPDATE-
Just an Update to the parts list. As I am currently building the board I noticed the 1/2 watt resistors are really too big to fit
when mounted side by side as in R25-R32, R12-R11, and R8-R7. It would be better to use 1/4 watt resistors throughout.
You might try...

( 1) 291-470-RC
(19) 291-1K-RC
(10) 291-4.7K-RC

These are still carbon film brown body resistors.

>Charles

jharre
November 16th, 2018, 02:01 PM
Thanks for the list, Dawsoca. I hope to building one of these soon.

Is there any reason NOT to use 1/4 watt resistors throughout as Charles mentions above? Half-watt seems kinda overkill.

<*> Jim

glitch
November 16th, 2018, 04:22 PM
The resistor used in the zener regulated supply (the 470R) probably needs to be 1/2W. The rest can be 1/4W.