In this blog I describe how I refurbished my hp battery pack 82033A.
In order to run the Printer 82143A or the Cassette Drive 82161A it is mandatory to use this battery pack, that can provide higher currents, which cannot be provided with the standard hp AC power supply.
The 82033A battery pack originally consists of 4 NiCad rechargeable batteries, 1,2 V. Naturally, after more than 30 years in service those batteries are not working anymore. Even worse, some of them are leaking.
The procedure to change the batteries is relatively simple...
You first cut the pack into 2 pieces, using a sharp knife or a little saw. Best method is to fix the battery pack in a vice, protected with a good amount of cloth, leather or similar.
After you have cut the pack open (you cut/saw all around the package, see picture below), you take out the old batteries, which you will separately dispose in an ecologically correct manner.
The old welded contacts at the battery terminal I ripped off the batteries using a plier.
I ordered new rechargeable batteries form Amazon: type Subc, 1,2 V, 3,0Ah, with soldering lugs, pre-charged. The battery capacity is now significantlly higher compared to the old NiCads.
In a next step you connect the new batteries together in a chain, consider the correct polarity. Then you put them back in the housing.
Very important: to ensure good contact between the soldering lugs and a proper isolation at both ends of the "chain". (The ends will come together in the housing, but must not connect each other).
For the contact plates for the printer / drive contacts I reused the old one, bending back the other end of those contacts and just put them to the related soldering lug. No soldering or welding needed, maybe a little piece of paper might be needed to ensure good contact.
In a final step I glued the two halves of the housing together using a cyanaocrylate-based adhesive.
Ready, almost new!
Printer and tape drive work again perfectly. I intensively tested the tape drive and its new battery pack (without AC power supply connected).
After a longer usage (I stored all my hp programs on tapes) the red BAT led flashed when the drive winded the tape forward or backwards. A clear indication that the batteries need to be recharged. I left the drive in the on-status overnight and next morning the battery pack was discharged. The voltage at the terminals was measured with 1,3V.
For charging I used the standard hp AC power supply. I measured the charging current in order to ensure that no damage will cause by a very high load current.
The charging current I measured about 200mA when the devices was switched off, when switched on the current dropped to about 120mA.
The maximum charging current of the batteries was specified with over 300mA when charging >10h. Quick and Fast Charge are specified even 2-3 times higher. The battery pack was not even got warm during loading. So everything fine.
After couple of hours charging the batteries the voltage at the terminals was 5.4 Volts. I stopped charging, I was not sure if a longer charging period could damage the batteries, since no intelligent charging electronic is used in the printer or tape drives.
The life time of the battery pack is difficult to predict, because the printer and tape drive is not used very often. It's more the love to and respect for the genius technology of the hp solution, which let you use the devices nowadays. They deserve it! :)