IBM Mainframe Forum

Hi All,

I found this old IBM circuit board in a trash dump by a local university, among hundreds just like it. This was in the late 70s I think, just rediscovered it in my loft. Would love to know what it is. Look at all those ICs! And wasted unused space on the PCB. My guess is it's something like a 256k RAM board. My son runs a high end game machine with 16GB ram that can fit in your palm. So doing the math, it would take several thousands of these to match that. I might be wrong, maybe it's not RAM. Kudos to whoever can identify this card. It measures 7 inches by 9.5 inches...about the size of a tablet today!

If ti's any help, the four grey IC's have IBM 52 printed on them.

Many thanks,

Tim

I did post this some years ago, but had no satisfactory or conclusive answers. Someone suggested it was a floppy drive controller, about the size of a frisbee back then. Anyway, I guess it will remain a mystery. Seems destined to be a museum piece...in my loft I wonder if a can get any money for it on eBay! Maybe enough for one coffee at Starbucks!

googling with "IBM52" returned about 2000 hits

Yeah thanks, but that doesn't solve the mystery. I did the same. I guess I'll never find out. Thanks all the same.

One thing is for sure, I''ll bet you could plug that old piece of junk back into it's mainframe, it it would work just fine. I have an old 486 PC and all the caps have popped. It'll never work again. This old IBM has no caps or resistors or anything. In fact, I wonder what the vertical IC circuits are. The amount of engineering that went into designing this old gem is amazing. Totally obsolete now. Somehow makes me more fond of it.

tjjohn61 wrote:I did post this some years ago, but had no satisfactory or conclusive answers. Someone suggested it was a floppy drive controller, about the size of a frisbee back then. Anyway, I guess it will remain a mystery. Seems destined to be a museum piece...in my loft I wonder if a can get any money for it on eBay! Maybe enough for one coffee at Starbucks!

There are people on eBay who pay fortunes for such old stuff, been there, sold one, shipping to the US from the UK was more than the price of the item. You can always donate it to the Computer Museum.

Thanks Robert, it's yours for 50 Euros! lol. I guess it will always remain a mystery. It was part of an old university mainframe, that's all I can say. Some hardware engineer in his 80s might be able to identify it. IBM52 is printed on most of the components, but googling IBM 52 returns a bunch of unrelated hits.

No luck so far, can anyone point me in the right direction to solve the mystery? It must be 70s era hardware. Some hardware engineers somewhere must have worked their butts off to design this! Thanks all!

Some of these photos look similar:
https://www.google.com/search?q=ibm+52+ ... 20&bih=889

Hi Terry,

Thanks a lot for the link, you're right, some very similar boards there. You know old mainframes had so many specific parts, I mean how many circuit boards can you fit into a server today? Not many. Those mainframes used to be the size of a garage, with hundreds of circuit boards. I'm glad I hung on to it, serves as a reminder of how far computing has come! Looks kind of austere, just silver and black. Tempted to pop the lid on one of those big ICs to see if I can view the micro-circuitry under a microscope. My guess is it's an old RAM circuit board.

Cheers

Tim