Mystery IBM processor

Dave Wade dave.g4ugm at
Sat May 28 06:40:39 CDT 2016

> -----Original Message-----
> From: cctech [mailto:cctech-bounces at] On Behalf Of Mike Ross
> Sent: 28 May 2016 11:29
> To: General Discussion: On-Topic Posts <cctech at>
> Subject: Re: Mystery IBM processor
> On May 28, 2016 9:51 PM, <malcolm at> wrote:
> >
> > Just wondering if anyone can help us to identify a rather large IBM
> > processor assembly. It weighs around 60 pounds.
> >
> > The frame has a P/N of 34F5089. The frame houses 9 modules, 6 of which
> > are installed. The module we removed for inspection has a P/N of 34F0615.
> Definitely IBM mainframe. The individual square alloy lumps are what are
> called MCMs - Multi Chip Modules. Insides are dozens of individual ECL ICs.
> Water cooling heatsinks would have been bolted to the front side in life.
> Can't remember what IBM called the entire assembly. 1980s, probably a 3080
> or 3090 but don't quote me on that.

I believe the modules are called TCM's or Thermal Conduction Modules. It looks like a 3090 chip but I thought those were withdrawn before the date code of "90xx".

I thought the ES/9000 follow on had a re-designed chip with multiple rows of pins like this...

but when I look at the IBM web pages:-

it says only the high end machines have the new TCM so I think it may be a TCM from an entry level ES/9000 machine...

> Mike


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