Threaded Mode | Linear Mode

WrongWay · 12-10-2020, 07:34 PM

I recently went on a rabbit hole excursion starting with slide rules and ending on calculators. I used an E-6B aviation slide rule in flight training so mechanical computing devices have a place with me. Then I noticed someone in a video talking about an HP*** calculator and I remembered that my dad had one and it was passed to me after he passed away in `89.
I went to my storage unit and sure enough I located his old HP-41CV with card reader, X-FUNCTIONS, AVIATION, and TIME pacs all installed. I pulled open the battery case and to my dismay the rechargeable batteries had long ago leaked out. But I was hopeful, the leak only appeared to be minor and confined one cell. Determined to get this thing working I located the alkali battery pack and bought new N cells, the rechargeable case was not salvageable. I cleaned the terminals using some white vinegar, cotton swabs, and distilled water and gently cleaned the corrosion off the terminals. I was ecstatic to find the terminal with the most corrosion was in fact quite minor and mostly surface damage only. Tragically the unit failed to turn on when the new batteries were installed. I pulled out a set of small screw drivers and with a nervous but steady hand began pulling off the rubber pads and gently pulling the case apart. It turned out the corrosion had gotten to the contact pad on the mid board. With the same process as before I removed the corrosion and lucked out, surface corrosion only no other damage. With the calculator reassembled and looking brand new, the pack was installed and after 32 years the MEMORY LOST message flickered then vanished. Determined not to be beaten, I gently partially reinserted the battery pack and the unit powered on, but on further insertion of the pack, the unit powered off again. After a couple rounds of gently coercing the pack in, VICTORY! The power remained on and the unit came to life.

Diving further into the bag of wonders I had brought back I found all the manuals:
"Owners Handbook and Programming Guide", "Operating Manual: A Guide for the Experienced User", "82182A Time Module Manual", "Aviation Pac" manual, "Standard Applications", "82104A Card Reader Owner's Handbook", "Games", "Games II", and a couple original overlays, high contrast, Stop watch, and blank with a full sheet of stickers.

Then I discovered the Magnetic Programming strips with titles. I tried to use the card reader but after disassembly noticed the drive wheel plastic tubing had shrunk over 30 years and was no longer able to pull cards through. The motor turned and everything appeared otherwise functional. I have a new card reader enroute, I hope the cards are still viable and I will be storing their contents on my PC if they are. I have had a couple fun days with this calculator and am amazed by how nice it it.

Maximilian Hohmann · 12-10-2020, 08:07 PM

Hello!

Yet another aviator on the forum :-)

(12-10-2020 07:34 PM)WrongWay Wrote: Then I discovered the Magnetic Programming strips with titles. I tried to use the card reader but after disassembly noticed the drive wheel plastic tubing had shrunk over 30 years and was no longer able to pull cards through.

Don't throw away your old card reader, all what's needed to fix it is a couple of o-rings worth a few cents to replace the rotten drive wheel. Forum member Mark Hoskins will certainly send you a couple for not much more than the shipping cost (last time I bought battery packs from him he put some into the package just for the fun of it :-) ).

Personally I am not the greatest fan of the HP-41 but I think I can see what others see in it. Enjoy your new discovery.

Regards
Max

WrongWay · 12-10-2020, 08:16 PM

Thanks Max. I still have the old card reader, I'm not planning on throwing anything out. I'm just totally blown away it still works. I guess the 32 years of storage in its small leather case, inside a box, inside a larger padded zip bag kept it from degrading. I bought the new card reader from ebay. either way spare parts are a good thing to have.

BobVA · 12-12-2020, 12:23 AM

Cool story - thanks for sharing it!

The magnetic cards are remarkably durable. Don't be surprised if you can read them all once you get your new card reader.

WrongWay · 02-23-2022, 05:43 AM

One year and some months on, the unit still works and gets regular use. I even have gone so far as to put go41CX and V41 on my phone and computer respectively.

BobVA · 02-24-2022, 01:31 AM

(02-23-2022 05:43 AM)WrongWay Wrote: One year and some months on, the unit still works and gets regular use. I even have gone so far as to put go41CX and V41 on my phone and computer respectively.

Excellent!! How'd it go reading your magnetic cards?

WrongWay · 02-24-2022, 03:25 AM

(02-24-2022 01:31 AM)BobVA Wrote:
(02-23-2022 05:43 AM)WrongWay Wrote: One year and some months on, the unit still works and gets regular use. I even have gone so far as to put go41CX and V41 on my phone and computer respectively.

Excellent!! How'd it go reading your magnetic cards?

I managed to get the old reader to do partial reads but the new card reader works quite well, although it seems to have developed a squeak when pulling cards. Some cards were unintelligible but they were records like old CC numbers.

The new card reader is how I pulled the JETLOG program and after careful transcribing and recompiling got it up on the forum for dissection. I get the inputs but the output is what is confusing. I'm currently on the hunt for an affordable HP-IL module so I can then get a PIL-Box.