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Ibm ps/1 help

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New2vtgpc

Experienced Member
Joined
Oct 22, 2019
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Iowa
Probably the first of many post but i recently stumbled(literally) on an old ibm at a yard sale and picked it up for 20 bucks. No cables or accessories but got generic moniter amd stuff to work. Its an IBM PS/1 model 2133-g49. It is all original with i486sx 25mhz, 2mb ram, 129mb hdd. It works but has a few issues that i need advice on.
1 is that it has 2mb ram but only shows 1600k (1.6mb)
2 is the software...it had old owner config and programs so I used the ps/1 fitness (took a day to find out how to find this)to make and use recovery disc but now boots to windows 3.1 instead of the ps/1 4quad ive been reading up on, so if anyone has any idea where to find or make the needed ibm software that came with this, or if this is normal.
3 is upgrades, this has an optional socket for an upgrade cpu but its not an overdrive or 486dx/dx2 but looks like only a 487sx mathco. 169 pin...am I wrong or can i not do any cpu upgrade to this?
I know nothing about ps/1 or ps/2 or even thr dos era but am learning as I go but this is the oldest pc ive messed with and am at a loss since I cant find much online except for info on the other models in the 2133 line but not much on the g49.
 
Welcome to the forums. I don't have answers for all of your questions, but here are a few things to note:

- The IBM PS/1 line typically has the power supply built into the monitor. Without the monitor, it's useless, so don't separate the two.
- The PS/1 you have is a 486sx CPU. The extra socket you are seeing is for a "487" upgrade chip: https://en.wikipedia.org/wiki/X87#80487
- The RAM difference might be normal based on how it is configured; it does not mean some of your ram is "bad".

Hopefully others on the forum can continue answering where I could not.
 
New2vtgpc said:
1 is that it has 2mb ram but only shows 1600k (1.6mb)
Click to expand...
Go into the CMOS setup. Look for a Shadow option. If it has this turned on it's using some ram to shadow the BIOS for faster operation. If you want that ram back you can turn this option off. It will not affect performance significantly.
 
Some mention of a 32MB RAM Maximum around the net. If you're thinking of doing anything serious (Win3x) then at least upgrade to 16MB. Not sure if the CPU upgrades; you might want to check this out:

http://ps-2.kev009.com/pcpartnerinfo/ctstips/4886.htm

Ignore the part that states " In fact, DOS itself can only recognize 16 MB of RAM total." In reality, DOS 6x would be able to natively recognize 64MB...
 
Trixter said:
Welcome to the forums. I don't have answers for all of your questions, but here are a few things to note:

- The IBM PS/1 line typically has the power supply built into the monitor. Without the monitor, it's useless, so don't separate the two.
- The PS/1 you have is a 486sx CPU. The extra socket you are seeing is for a "487" upgrade chip: https://en.wikipedia.org/wiki/X87#80487
- The RAM difference might be normal based on how it is configured; it does not mean some of your ram is "bad".

Hopefully others on the forum can continue answering where I could not.
Click to expand...
Only the early PS/1 286-386 models had the psu in the monitor. A quick google search would have determined that. They also had propriorory hdd and fdd connections.The rest of the line did not. I've owned two of them. I suggest the OP pop on over to Vogons.org as there is a chap there who has a passion for the later PS/1s. As well as quite a few discussions on the later PS/1 line as well as links to resources such as manuals and recovery CDs in the Marvin section.

For the OP the PS/2 line came before and was mainly micro channel architecture. IBM saw the error of there ways and introduced the PS/1 line and the PS/ValuePoint linein parallel to try and pull back some of the market share they lost producing the PS/2 line. PS/1 and PS/ValuPoint use standard FDDs and HDDs used by the rest of the industry at the time.

The 487 in you system is just a 486 with an extra to disable the on board SX processor and really a marketing gimic.
 
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The g49 is just a variation of the 2133 line ie just a configuration difference. Nothing particularly special about it. You got it a a good price. The maintenance/service manual is readily available for the 2133 range, covers other models in the PS/1 line up as well and has diagnostic tables. Any PS/2 mouse and keyboard will operate with it as well as any VGA monitor. It has ISA expansion slots for adding the likes of network or sound cards.

What version of Dos is it running? There are versions of the 4Quad menu for Dos 5 and 6 available for download on line. The earlier 286-386s had it in rom on top of MS Dos 4.01 but you had a choice to boot another version of Dos from the proprietary HDDs.
 
Is that the "PS/1 Consultant"? I had one of those and upgraded the cpu with an Overdrive chip in that slot. I've since aold it to my friend but I can have him take a look at the model of overdrive chip if you want to upgrade yours, although mine may have been the 33mhz version so you might need a slightly different chip. I love those machines, they're really cool looking, especially when they still have the door on the front.
 
I believe its running pc dos 6. I havent checked the version of it by what info ive dug up, its a fall 1993 model and those *usually* came with 6.1. Ive currently got it torn apart doing a deep clean, (was in garage upside down for 20yrs so rubber feet melted and ran all over case and was full of dust.) It was basically sittong on table in pieces when I fired it up and got the boot screen.
 
Yep. Says consultant on the front. And from what I found most* of them came with the sx 25mhz, but from pics of othrr 2133 models the extra cpu socket is either the light blue one labeled overdrive (for 33,50,66 cpus) or brown and has 169 holes. Mines the brown one and the only one ive found so far is the i487 (which is exacr same cpu as current but with the extra features so not really gaining anything) kinda fun learning bout these old for machines but damn it seems theae ps/1 are bit obscure
 
Yea...i downloaded a maintenance pdf for thr 2133,2155 and...another line that im fogetting and it says mine has a max of 32mb for this model. But yea I read up that dos 6x *can* have 64mb which makes since since win95 wanted minimum 8 to 16 and 98 wanted 32 if I remember right.
but not sure if thats all dos or just ms dos (since I guess there was a slight difference from what ive read)
 
Would this be in the bios config screen or is this in the "ps/1 fitness" section of os? Or better question would be how to get to cmos setup on this?
 
It must be ps/1 season :D - I just got one for free on CraigsList! Mine's a 2155-G44 with a 486sx at 20MHz.
I've also been looking into upgrade options. On the board in my machine, I have the empty 487 socket, but the 486sx is also in a socket. There's also a jumper to select SX or DX processor. Would it be possible to just swap out the SX chip for a DX or DX2 rather than having to find a 487 or overdrive chip?
Also, I don't see any obvious way to set clock speed on either the board itself or in BIOS. Are these boards configurable in some other way or is it stuck at 20MHz?
 
--Update--
Got it working and all put together. Luckily IBM put a recover program inside the os that allowed me to make all new restore and software floppies. And I dont need to hunt for the 4quad screen since my model was the one that didnt have it.
Found some more memory...guess it's picky and HAS to have parity ram so I got some ordered and coming . just the cpu upgrade stalling me. The 486sx is soldered but right next to it is a black or brown 169 pin socket, doesnt say over drive, nor does it say 487. From other models in the 2133/2155 says I can use a 33mhz dx or 50mhz dx but other sites say i have to use a 25mhz dx. So im lost there, hopefully someone knows the exact cpu I can use for this. Other than that. So much fun playing on an old dos/win3.1 pc
 
bubish said:
It must be ps/1 season :D - I just got one for free on CraigsList! Mine's a 2155-G44 with a 486sx at 20MHz.
I've also been looking into upgrade options. On the board in my machine, I have the empty 487 socket, but the 486sx is also in a socket. There's also a jumper to select SX or DX processor. Would it be possible to just swap out the SX chip for a DX or DX2 rather than having to find a 487 or overdrive chip?
Also, I don't see any obvious way to set clock speed on either the board itself or in BIOS. Are these boards configurable in some other way or is it stuck at 20MHz?
Click to expand...

I'd assume you could swap the sx for a dx. Mines soldered with a 169 pin socket nearby. From a hardware PDF I downloaded your model *should* be able to be pulled and a dx class dropped in and a jumper moved to be faster. And as far as ive found (which wasnt much), the 487 was just a 486sx 25mhz but with the coprocessor built in unlike the 486sx which didnt have it built in for cost measures. Mainly a marketing gimmick from what I was told. I think once you put in a new cpu, change jumper, and run the configuration settings it *should* adjust. Might be a good idea to Google and download the hardware PDF for the 2133 line. Has a lot of useful technical info for these.
 
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