On eBay: Clone Micro-ATX Backplates

General discussions related to the Altair 8800 Clone

On eBay: Clone Micro-ATX Backplates

Postby steve_a » February 28th, 2019, 2:31 am

Here's the link (Updated 11/17/19 to change the category the backplate was in):
https://www.ebay.com/itm/Altair-8800-Cl ... 2850265368

UPDATE 11/10/2019: Back on eBay! Asking price has been modified to $90 + 19.95 shipping. I have flat-rate boxes that the backplates fit into much better than what I was using before - and shipping was a mess last time. Still $110 total. I know I said I'd try and sell directly, but having the eBay storefront is still too convenient to pass up.

Old thread with more pictures:
viewtopic.php?f=2&t=213

20190223_165625 (Small).jpg


Installation notes for the Altair Clone:

The backplate is provisioned for three db-25 serial ports. Two come stock with the Altair. The stock wiring for COM1 and COM2 reaches the db-25 cutouts, but it is recommended to extend the wiring to keep it out of the way (DB-25, 5-pin 3.96mm VH connector, ribbon cable). The 3rd DB-25 cutout is for the cassette interface (if installed).

Depending on the motherboard standoffs used, the cassette interface circuit board may need trimmed. Where it needs cut there is no circuitry, and the cassette interface has been tested working after cutting off this piece of its circuit board, like so:
20190222_204219 (Small).jpg


Like COM1 and COM2, the ribbon cable for the cassette interface reaches where it needs to go, but it is recommended to extend it.

There is NO provision for the stock power supply for the clone. Either arrangements have to be made to use it (drill some holes) - or - modify the clone circuitry to run off of 5V instead of 12V (a single wire needs to be soldered on the clone's board) and use the 5V standby voltage from an ATX power supply (see below)

There's enough room beside each 3.5mm audio jack for the "TAPE PLAY IN" and "TAPE RECORD OUT" stickers, and enough room under the PCI cutouts for the Altair Clone's serial number sticker. The serial number sticker is known to lose its text during transfer, so be careful.

Installation notes for the Micro ATX Motherboard:

20mm motherboard standoffs MUST be used. This allows room for cable management and, more importantly, leaves room for the Altair cassette interface. It is recommended to use female-on-both-ends standoffs to gain wiggle room during installation.

The ATX power supply is very close to the plate mounting holes on that side. Standard 1/4" #6-32 case screws will fit without touching a power supply.

There are cutouts for two 92mm cooling fans. It was designed to allow installation of an Asetek 645LT AIO liquid cooler in the cooling fan cutout closest to the ATX power supply. (well, it was designed for the discontinued 545LC, they have the same footprint though). A Hardware Labs Black Ice Nemesis 92mm radiator WILL FIT.... if you leave it and the power supply loose and tighten them both down at the same time. They WILL BE TOUCHING. There's one of them installed in one of the photos of the eBay listing.

The PCI cutouts are designed to use the edge of the motherboard as the bottom PCI anchors. So before tightening the motherboard down, ensure there's enough room for the bottom of PCI cards to slide between the plate and the motherboard.

If using a screwdriver, the PCI mounting screws are hard to get to with the DB-25 serial ports in place.
Last edited by steve_a on November 17th, 2019, 2:43 pm, edited 15 times in total.
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Re: On eBay: Clone Micro-ATX Backplates

Postby steve_a » February 28th, 2019, 2:42 am

For the power requirements, here's what I did.

To run the board off 5V:
AltairClone wrote:Tack on a jumper wire where shown by the yellow line to configure the Altair Clone PCB to run from 5v instead of 12v.

Mike

Image


And I used the 5V standby voltage off the ATX. It is hot all the time, even if the rest of the ATX supply is off, so the clone can run independent of the micro-ATX motherboard. The +5V standby is normally rated for 2-3A and the clone only draws 40mA, so that should be fine. +5VSB (and COM) in this pinout:

Image

Works like a champ.
Last edited by steve_a on November 10th, 2019, 11:29 pm, edited 1 time in total.
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Re: On eBay: Clone Micro-ATX Backplates

Postby steve_a » April 23rd, 2019, 11:47 pm

When I designed the plate I had provisioned a 92mm Asetek 545LC all-in-one liquid cooler to fit in one of the fan cutouts.

In December 2018, Asetek discontinued the 545LC. I was not happy. I purchased a Hardware Labs Black Ice Nemesis 92mm radiator and it does "fit", but mounting a pump and reservoir really started to get cramped.

UPDATE 7/24/19: Asetek has released the followup to the 545LC, the 645LT. It is the same size as the 545LC and fits on the backplate with a 2nd fan next to it with no issue.

So there are (at least) two options for liquid cooling with the backplate. Hardware Labs Black Ice Nemesis or an Asetek 645LT or possibly (UNTESTED) Alphacool NexXxoS XT45.
Last edited by steve_a on July 24th, 2019, 9:26 pm, edited 2 times in total.
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Re: On eBay: Clone Micro-ATX Backplates

Postby TomXP411 » June 27th, 2019, 3:25 pm

Do you still have any of the back plates? I just ordered a Mini ITX motherboard, and I'm debating whether to install it in my Altair Clone or to order a small form factor case for it.

If that's not a viable option, I may find a 19" rack mount case and Frankenstein something together.
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Re: On eBay: Clone Micro-ATX Backplates

Postby steve_a » July 24th, 2019, 9:15 pm

TomXP411 wrote:Do you still have any of the back plates? I just ordered a Mini ITX motherboard, and I'm debating whether to install it in my Altair Clone or to order a small form factor case for it.

If that's not a viable option, I may find a 19" rack mount case and Frankenstein something together.


At the moment, no. I have to order a few more next chance I get and post them back on eBay (and sell them directly this time, eBay ate into my $2.00 profit on each one :-D)
I'll let everyone know when I acquire some more.

(edited): It looks like mini-ITX shares mounting holes with the ATX/Micro-ATX. So that should work. The PCI slots will be empty, but those are easily covered.
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Re: On eBay: Clone Micro-ATX Backplates

Postby TomXP411 » July 29th, 2019, 12:41 pm

Thanks for the update.

I ended up buying a SFF PC case and moving the HDD out of my NUC, along with a new SSD. So I'll eventually find a way to mount the NUC inside the Altair Clone, but I've got a ton of other projects on the burner, first.

What I'd really like to find... I'm not sure exists. The developer boards (like the Pi) all have ports on too many sides to be easily usable in a situation like the Altair Clone, but small form factor computers like the NUC don't have a lot of mounting options.

I could use my nibbler to make a hole the size of the NUC's rear panel, but I can't access the power button if I mount it inside the case.

What I'd really like to find is a mini PC about the same size as the NUC, but designed to be installed inside of a larger enclosure - basically a PC designed for embedding. I almost bought an Atomic Pi for this use, but it's just too oddball to make me comfortable.
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Re: On eBay: Clone Micro-ATX Backplates

Postby managed_mischief » August 31st, 2019, 6:08 pm

hey there, just wanted to express interest in a back plate from the next batch and say thanks for going to all the trouble
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Re: On eBay: Clone Micro-ATX Backplates

Postby steve_a » October 26th, 2019, 9:30 pm

managed_mischief wrote:hey there, just wanted to express interest in a back plate from the next batch and say thanks for going to all the trouble


Next batch has finally been ordered (got hung up on the road a bit with work recently), I'll let you know when they've arrived!
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Re: On eBay: Clone Micro-ATX Backplates

Postby steve_a » November 10th, 2019, 11:31 pm

steve_a wrote:Next batch has finally been ordered (got hung up on the road a bit with work recently), I'll let you know when they've arrived!


They've arrived and have been relisted on eBay. The link is in the original post.

(Updated link 11/17/19)
Last edited by steve_a on November 17th, 2019, 2:09 pm, edited 1 time in total.
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Re: On eBay: Clone Micro-ATX Backplates

Postby managed_mischief » November 14th, 2019, 8:15 pm

thanks, just grabbed one. did you say somewhere you had the cad files as well? if you had the altair drawn up id love to grab that from you
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