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Anyone repair or take apart a Corvallis Microtechnology (CMT PC-5) (pc5-eb)?

barythrin

Veteran Member
Joined
Oct 5, 2005
Messages
6,256
Location
Texas
I'm not easily finding any good references to repair/disassembly for these PC-5 systems. They're a hand held computer that apparently has a minimal dos 5.0 load and an 8088? chip so it's "compatible" with already compiled programs you could technically transfer to it via the serial port and kermit protocol (one I have works and counts 640K ram which is amusing) the other just makes a horrid buzzing noise when plugged into a power source. Obviously I'm guessing the battery or a cap is shot inside but was hoping to look at some guide to repairing these. Unfortunately most of what I find leads to the fairly nondescript corvallis website which no longer references these units and certainly seems like they used to just have you ship them the unit and fix it for hundreds of dollars.

Anyone play with one of these? This http://www.cmtinc.com/techhelp/pc5faq.html is pretty much the most information I've come across so far but nothing really about the insides. They have an ftp I looked briefly through but it also seems to concentrate on using the newer models and not anything regarding repair that I could find. Really I would think they'd have something somewhere on replacing the battery as an FRU but perhaps they weren't intended to be field replaceable?

It seems like it was popular with folks doing geological and forestry studies. Certainly looks more like something you'd find in a warehouse than a home though. I tried on the classiccmp mailing list but no response there lol. I haven't tried too much as the screws weren't budging from my first attempt but I also had a smaller screw driver and thought I was going to strip the screw or they may have used some sort of sealant on the screw. Any tips would be most welcome.

Here's a picture of one.
pc5.gif
The reason I was intrigued was the text on the systems that says "MS-DOS 5.0".
 
Last edited:

Hoseman292

New Member
Joined
Aug 3, 2016
Messages
2
Hi Barythrin,

How did you make out with your Corvallis MicroTechnology PC5-L? I own a PC5-L and a MC-GPS model and attempting to build a power supply for them. Any idea what the input voltage / wattage requirement is? It's certainly constructed very well and it's size reminds me of handheld oscilloscope I've owned for years.

I'm interested in just having at least one of these boot to a DOS Command Prompt. I read of CMT's BURN-FS utility which could be used to flash the EEPROMs but lost interest with the $275 charge. I haven't accessed the battery compartment but if they're shot I'll likely rebuild them with lithium ion rechargeable
cells.

I've had success booting DOS with Intermec's JANUS 2010 / 2020, and PCL 1100 handheld computer / data collectors.
 

Hoseman292

New Member
Joined
Aug 3, 2016
Messages
2
Still searching for any information on programming. Replaced the batteries with 1600mah cells recently in three CMT devices.
I used batteries with solder tabs and small lengths of 20 gauge stranded wire to connect each battery to allow the spacing requirements so each battery could be positioned and secured within the housing. Replaced the screws which attach the battery case and powered without any problems.

Hi Barythrin,

How did you make out with your Corvallis MicroTechnology PC5-L? I own a PC5-L and a MC-GPS model and attempting to build a power supply for them. Any idea what the input voltage / wattage requirement is? It's certainly constructed very well and it's size reminds me of handheld oscilloscope I've owned for years.

I'm interested in just having at least one of these boot to a DOS Command Prompt. I read of CMT's BURN-FS utility which could be used to flash the EEPROMs but lost interest with the $275 charge. I haven't accessed the battery compartment but if they're shot I'll likely rebuild them with lithium ion rechargeable
cells.

I've had success booting DOS with Intermec's JANUS 2010 / 2020, and PCL 1100 handheld computer / data collectors.
 

kyodai

Experienced Member
Joined
Jan 26, 2011
Messages
467
Location
Kerpen, Germany
It's a normal MS-DOS 5.0 Computer with monochrome CGA display, so to program for it anything around Quickbasic, "Visual Basic for DOS", Assembler, pascal, C++ and such would work for programming. Not sure which graphics modes it supports, but text mode appz should work fine.
 
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