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Monroe 325 Scientist
01-16-2016, 06:12 PM
Post: #1
Monroe 325 Scientist
Hello all,

Just recently had a bit of good fortune mixed with a minor disaster.
Was pursuing TAS in the vinintage computing stuff and spotted a strange looking calculator with lots of buttons, after a hurry up Google search search, and with what the seller was asking, I decided to risk the purchase.
After some hassle with the shipping, the unit arrived, boxed with a single layer of bubble rap and some newspaper. Apparently, this box was heavier than it appeared as it seems it was dropped several times.
After careful removal from its meager wrappings, my heart sank at the carnage that was revealed. The bottom rear corner near the AC connection was broken away and most of the bottom front was shattered. The top she'll of the 325 did survive mostly intact with only the right rear internal screw post broken.
After a few days of fitting the puzzle pieces back together, and fashioning a new power cord, I'm pleased to say that the 325 seems to operate without flaw. Will need to secure a ribbon and paper for the printer, but even it appears to be functional.
The original listing did show that the paper cover a piece broken away as well as several missing key caps. I hope to make a mold and re-create the missing caps. After scouring Google and reading all that I could find, this is a pretty fantastic piece of kit (although I'm still partial to HP's offerings) and am looking forward to learning more.
I'm now on the look out for the 392 tape drive. Is there an alternative tape drive that anyone is familiar with?

Tom
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01-16-2016, 09:57 PM
Post: #2
RE: Monroe 325 Scientist
I have a 325 and a 326, both use the same 392 tape drive. I've never seen another drive that works with these calculators. Keep in mind that Compucorp made these machines for Monroe so look for the Compucorp 392 tape drive too, it's identical. They do show up on ebay once in a while.

-katie

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01-16-2016, 10:19 PM
Post: #3
RE: Monroe 325 Scientist
Yes, I've got a search set for Compucorp and Monroe and Sumlock for the 392 drive. Also borrowed a download of the Service manual for the 392 from your site to see if there was a chance to convert a different datasette drive to operate 325. Think I'll wait for a 392 to pop up.

Thanks,
Tom
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01-17-2016, 04:05 AM (This post was last modified: 01-17-2016 04:05 AM by Katie Wasserman.)
Post: #4
RE: Monroe 325 Scientist
(01-16-2016 10:19 PM)Tom Ward Wrote:  Also borrowed a download of the Service manual for the 392 from your site to see if there was a chance to convert a different datasette drive to operate 325.

The full schematic and parts list is all there. The electronic components should all be pretty easy to find and the circuit layout isn't critical as this is very low frequency stuff. The cassette mechanism looks like a standard (1-7/8 ips) drive as does the tape head. If you wanted to try building your own I think the circuit is designed to control a 6 volt (probably 4 x C cell) motor transport mechanism. These were extremely cheap and common back then.

If you do that let me know and I can possibly help with some voltage measurements, etc..

-katie

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01-17-2016, 05:13 AM
Post: #5
RE: Monroe 325 Scientist
Thanks for the offer.
I need to scrounge up a schematic of a similar cassette deck and compare it to the 392's to see if there's a possibility to make the 325 happy with it. I probably need to just chill and wait for a 392 to show up. This is where I usually make magic smoke happen. :-)

Tom
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