IBM PS/1 Model 2011

[explorerzach]

Hello all. Theres a local listing for a IBM PS/1 near me for $75 i will be purchasing soon. I was wondering if there is any way to upgrade the CPU? I'm not familiar with IBM computers but i know you can upgrade Macintosh CPUs.
PS: this is the model with a 10 MHz Intel 80286 CPU
Thanks
-zach

 

[MausolfB]

The 80286 in the PS/1-2011 is not upgradeable; it is a PLCC-68 style soldered directly to the mainboard.

Couple of things to keep in mind about the IBM PS/1-2011... First the date/time and CMOS is supported by a Dallas DS1287 RTC chip. These real-time clock chips have an average lifespan of 10 years and will more than likely be dead in the unit you're looking at. You'll get error codes 161, 162 and 163 every time at startup if that's the case; You also will not have a functional floppy drive as that relies on the configuration settings (which aren't being saved if the DS1287 is dead). The chip however is removable and can either be replaced with a DS12887+ to keep it simple or if you want to try can cut away some of the housing of the dead one, cut the built-in battery leads and solder on a CR2032 holder.

Speaking of the floppy drive they also have a tendency to fail and not operate even with a new/repaired clock chip. You can't simply drop a typical floppy drive in its place as a replacement as the PS/1 has a slightly different pinout setup than a standard floppy; for instance +12v and +5v are supplied through the ribbon cable and not through a seperate 4-pin molex as with a typical drive. Therefore if you drop in a new floppy drive unmodified you'll destroy the drive. Also there's a drive type pin on the ribbon that has to be pulled to ground in order for the system to treat the drive as a 1.44MB 3.5" drive; otherwise it'll be treated as a 1.2MB 5.25" drive and won't work properly.

Another item of note is the hard disk. The PS/1 has a 30MB HDD (WDL-330P) that uses a proprietary 8-bit XT-IDE interface; it uses an edge connector which like with the floppy drive provides +12v and +5v alongside communications (so no 4-pin molex for power). Since the interface is proprietary to IBM the drive can be difficult to source if it has failed and you want it replaced (error code 1701 will show at startup if that's the case).

Power for the system comes through the monitor via a seperate cable alongside the VGA cable; there is no separate power supply within the system. Lastly the Model/2 keyboard has capacitors inside that tend to fail from age and thus the keyboard tends to be "stuck on" when the computer starts. You'll get an error code 601 at startup if that's the case and a lot of beeping like a key is stuck (the Caps lock and Scroll lock lights tend to be on too when that happens).

Good luck on the PS/1-2011. Is this the one you're looking at?

 

[modem7]

The chip however is removable and can either be replaced with a DS12887+ to keep it simple ...

Is that established fact for the PS/1-2011, or an expectation ? (obviously, the two things are different.)

If established fact, I will add an 'IBM PS/1 2011' entry to the to the 'Some known compatibility/incompatibility' table at [here].

 

[MausolfB]

Is that established fact for the PS/1-2011, or an expectation ? (obviously, the two things are different.)

If established fact, I will add an 'IBM PS/1 2011' entry to the to the 'Some known compatibility/incompatibility' table at [here].

I've been using a DS12887+ in my own PS/1-2011-C34 without any trouble. The DS12887A+ could also be used if the former can't be sourced; The A's extra reset pin is not utilized on the 2011 mainboard.

 

[modem7]

I've been using a DS12887+ in my own PS/1-2011-C34 without any trouble. The DS12887A+ could also be used if the former can't be sourced; The A's extra reset pin is not utilized on the 2011 mainboard.

Thanks. I have updated the 'Some known compatibility/incompatibility' table at [here].

 

[explorerzach]

Yes, that is the ebay listing.