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Kanderson0
June 5th, 2017, 04:26 PM
Can someone out there tell me what ics I need to get to upgrade my ram in my model 25 8086. I have the parity slots full with the 512 but I need the extra 256 in the 6 slots near the bios

evildragon
June 13th, 2017, 08:36 AM
I'll find out in a bit off my 25. Give me a few hours if no one else responds.

I'm fairly certain it's actually 128k in those dips, not 256k like some sites say.

evildragon
June 13th, 2017, 08:53 AM
Actually I got out of bed and just did it now, here you go.

https://i.imgur.com/2vcSsl9.jpg

I was right, those DIP's are NOT 256Kbytes total. Each memory chip is 32K each, totalling up to 128K. The websites online are incorrect.

EDIT: Oh, and greetings, from my model 25: http://i.imgur.com/94sSaGE.jpg

PS: The slots with 512, are not parity slots. It's just a simple SIMM memory slot.

chulofiasco
June 13th, 2017, 12:36 PM
i've got these in stock. send me a message and we can work something out. i have pulls available.

chulofiasco
June 13th, 2017, 12:37 PM
Actually I got out of bed and just did it now, here you go.

https://i.imgur.com/2vcSsl9.jpg

I was right, those DIP's are NOT 256Kbytes total. Each memory chip is 32K each, totalling up to 128K. The websites online are incorrect.

EDIT: Oh, and greetings, from my model 25: http://i.imgur.com/94sSaGE.jpg

PS: The slots with 512, are not parity slots. It's just a simple SIMM memory slot.

your model 25 is great ! gave me the idea for the pocket Ethernet for mine... you need an ssk for it... =)

evildragon
June 13th, 2017, 01:22 PM
I use a Xircom PE3 on mine, and it works great. I've also added VGA to mine, and made a loop back port in the 15-pin bunch-out in the back, to allow any VGA card to use the internal CRT, as long as EGA 350 line, or anything else it doesn't support, is used. (EGA 350 it technically can sync, but the monitor in the 25 only looks for vertical sync polarity to detect modes, 350 line on a VGA card uses horizontal sync polarity also so it just doesn't sync).

chulofiasco
June 13th, 2017, 05:06 PM
I watched your video on YouTube a few times. Lol

My model 25 has undergone some tinkering. In an attempt to internally mount a SCSI adapter, extending the expansion bus to a third "slot", allowing for other features, (sound and networking, or whatever), I drememeled the port to accommodate an 25 pin SCSI port.

The Xircom device and a move to an apartment with not as much tinkering space has halted the continued abuse of the subject, but, I will confirm it is possible, I tested the third "slot" with a token ring card, and the card was detected, and passed diagnostics.

I would have had the whole thing completed, except big blue, in their devine and infinite wisdom in design, created the monitor shielding to extend probably an additional six inches down, filling the space that should be opposite the riser.

I don't know if you've got Instagram, but if you do, search #model25project -- I've got all kinds of pics to the things I've done to the device. I've named it Piggy because of the consideration it gives to my whims. One of the coolest things about it is that inside is Glitch's XT-IDE board, but he tricked it out with mil-spec components and an industrial DOM. Aside from some weirdness with the second floppy, which in all honesty i havent attempted to diagnose yet, it's a really nice addition, and his work is sweet. (Thank you, sir !)

I guess the model 25 was my first love, I've since had my way with plenty of her cousins... LOL

chulofiasco
June 13th, 2017, 05:07 PM
I've got this twisted desire to use the TR Xircom and put this 8228 under my desk to some use.

evildragon
June 13th, 2017, 07:08 PM
Just found your pics, looks like you also did a VGA mod yourself, nice.. I see you have a color model too. Does the 350 line EGA mode not work on the color model also, like the monochrome model? The tech ref manual infers it won't, but I'm curious.

I had a very similar idea about using a 3rd ISA card, and I was going to make the 3rd ISA card be the XT-IDE, so I can use something else in the regular slots, like one of those 286 turbo cards (V30 is nice, but I need a real 286 sometimes).

chulofiasco
June 13th, 2017, 07:20 PM
I tried to put the VGA mod together, I didn't succeed... then again, I was overly ambitious trying to mount to the underside instead of taking the plug assembly off, which is why I thought your passthrough cable was genius ! Lol

I've got a V30 in mine as well.

I started with a monochrome model, I had purchased the screen from some ass reseller on eBay.

evildragon
June 13th, 2017, 08:09 PM
Ahh.. I originally had a VGA card I modified for my system, desoldered the VGA jack entirely and soldered the wires over to it straight, but back then I just tied the RGB lines together and turned down the brightness (no weighted grayscale).

Ultimately when I decided to upgrade the video card to the VGA Wonder XL, that's when I documented it and did the passthrough, but also learned what sense lines to tie to ground, to tell the video card it's a monochrome monitor, so it properly treated it as suched and switched out the color palette for a monochrome one. This allowed proper weighted grayscale. Only time though this actually failed, was when trying the 8086 Wolfenstein 3D port (which also didn't run correctly at all), but also VESA 640x480 modes like 32k colors.. Those sadly just send the monitor only green and that's it. I actually have schematics drawn out to do a proper weighted greyscale with resistors, without needing the card to do it, but I got lazy and never implemented it, since it's not like it was a big deal anyway.

chulofiasco
June 13th, 2017, 08:55 PM
These things take a tremendous amount of abuse and thrive.. I wish the plants I had outside were as well prepared... lol

evildragon
June 15th, 2017, 05:02 AM
Haha, well my plants are still alive, then again, it's been raining every day here so far..

But yea, they are resilient machines. I just wish those motherboard upgrades for it were more common, as I would have loved to run some more modern software on it than be limited to an 8086. I was going to make a Raspberry Pi motherboard for it, but opted not too as it breaks historical nature of the machine too much (whereas the upgrade motherboards were specifically designed for this machine).