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WTD: PCjr 128k IBM Sidecar Mod for 736k Total

H

hexsane

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mbbrutman I know you have this hidden away somewhere. :)

I have my system up to 640 with the jrHotshot II (need to add clock chip to that too).

Anyone else have it? I've been searching google and all I've come up with is a file that tells me to get an MSBooster for 736k then explains how to do the sidecar mod for 512k . :mad:

I was disappointed to find out I couldn't do it with a jrCaptain unless you have a jrCadet. :mad:

Its just one of those nights I guess...

-Matt
 
I have been serving as an unofficial parts depot and adoption agency for PCjr parts for about 6 or 7 years now. (I've posted about quite a few free machines here, but nobody ever responds.) Believe it or not, I'm running out of the desirable stuff. To get an IBM memory sidecar I'll have to start cannibalizing machines.

A lot of the stuff I rescued locally from people who were giving their old junk away. That was around 10 years ago and they were happy to have their stuff leave the closet. Another stash came from the Eugene, Oregon PCjr club which was actively supporting the machine up until about seven years ago. (Those guys were gems - a real "old school" computer club.) And quite a bit was purchased on eBay - if I saw stuff cheap I purchased it and put it in the stockpile. I've even spent evenings while on business trips procuring parts where I was traveling - yep, imagine going through an airport with sidecars. ;-0 (Erik helped me ship the rest of that stash home.)

If you think you are going to be in this for the long haul, scan eBay and don't let the cheap stuff go without bidding on it. I picked up a lot of my personal collection that way over the last 10 years. But in the last two or three years I've not had the stomach for it anymore; eBaying is a hassle and I think I have everything I'll need for a while. My priorities have changed - I'm really enjoying the programming part which isn't limited to a specific machine.

Snap up what you can cheap. Scan Craigs list. And don't throw anything away - if it's not working it can probably be repaired fairly easily.

As for the IBM memory sidecar, I'll keep an eye open. But you know, in all of my years with the machine I've not needed that much memory on one. (That's right - I haven't don that modification, nor plan on it. But I can help you when the time comes to do yours.)
 
FWIW, I have signed up Andrew Lynch to help out with the PCjr version of the XTIDE controller, which will also double as a 640k sidecar expansion. I'm sure Mike will want to jump into this too.

If you have a 128k sidecar now, you would open it up, gut the PCB, insert the PCB we manufacture. Our PCB should have:
1) 640k of SRAM http://www.vintage-computer.com/vcforum/showthread.php?23065-Adding-SRAM-to-a-8088-PC
2) Fully functioning IDE controller
3) room on the back end of it for an IDE-CF adapter or possibly microdrive (both?).

Not trying to push vaporware here, just trying to guage interest and start a new project rolling. We're still in the planning stages to see if it's possible, but I am pretty sure all the pieces are available, we just need to get started.
 
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Yes yes yes ... Mike signed up a long time ago. :)

And if you want to test the BIOS before the sidecar is created, we can use an existing XT-IDE in my ISA bus adapter with a different BIOS. I don't think the BIOS will be much different from what you have.

I have part numbers for the sidecar connectors that attach to the system bus, but they are not in production so they are expensive. (Something like $10 to $15 per set on the secondary market.) We can use wide IDC headers as a substitute - the spacing is correct.

(Note to others - save your dead sidecars - you will need the shells.)


Mike
 
Actually I just need the modification. I have the sidecar.

I'd definitely be interested in an IDE / RAM combo (simply for lower power consumption)

I snagged a system locally from craigslist that had a monitor, jrHotshot and other stuff. I already had 3 systems but no monitor and didn't feel like making an adapter. Now I've gone and come up with a purpose for the machine so I want to get one put together. :)

I've noticed on the machines that the connectors in the back tend to get mangled :/

-Matt
 
I should reiterate that it probably doesn't matter which sidecar you end up gutting for this particular project, but it makes the most sense to use the memory upgrade one because you won't lose any functionality. You could very well take an LPT sidecar and remove the PCB from it, but then you've got no printer port. This is all because you need to re-use the plastic housing.

I believe also that our PCjrXTIDE640k (need a project name!) might have to be the last sidecar in the chain, as we will likely not get the connectors for the passthru.
 
Hmm. I know it was unintentional but this did become somewhat of a thread hijack. :)

What it started as: I'm looking for the information on modifying an IBM 128k sidecar so it will fill in the 640k-736k memory area.

Back to your irregularly scheduled hijack... :)

-Matt
 
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