More Museum Finds and Help with Disk Needed

From: Joe <>
Date: Thu Mar 28 19:11:52 2002

At 07:50 PM 3/28/02 +0000, you wrote:
>> >7. hp 97 calculator missing adapter and battery.
>> The adapter puts out 8 volts AC. The battery has four sub-C NiCad
>> cells so it has 4.8 volt output. It should be easy to find an AC adapter,
>It's the same battery pack as is used in the 82143 (HP41 dedicated
>printer), 82161 (digital tape drive) and 82162 (HPIL thermal printer).
>And all the HP90-series ('Topcat') calculators.
>It is just 4 Sub-C NiCds in series. I can look up the polarity of the
>contact springs in the HP97 battery compartment if you need it.
>> the adapters that are used for the rechargeable battery packs in the HP-41
>> and for nearly all of the HP-IL devices fits and works fine on the 97. I
>There are 2 types of HP97 charger connector (!).

  Actually there's about 6 or 7 if count all the foreign versions.

>The latter, and more common, one has a ridge in the middle. It takes the same
>charager as is used with many later calculators (HP10A, HP19C (I think
>those 2, anyway), HP41 rechargeable pack, HP71, HP75), and many HPIL
>peripherals (82161 tape drive, 82162 printer, 82163 video, 82164 RS232,
>82165 GPIO, 82168 Modem (I think), 82169 HPIB, 9114 disk drive, 2225B
>thinkjet). And also on the 82143 HP41 printer, HP110 'Portable' and
>HP110+ 'Portable Plus' MS-DOS laptops, and doubtless a lot more that I've
>forgotten. These adapters are not hard to find.
>The earlier series have a slightly different plug. I am not sure if the
>later charger will plug in (I do know an old charger will not fit the new
>machines). There is no ridge in the middle -- just 2 pins. Electrically
>the chargers are indentical.

   The plug on the old style charger is strange. It has a web in the middle but the web is cut at angle so the plug can only plug in one way. The newer charger has the entire web cut out and will plug in either way. Bear in mind that both chargers output AC so polarity is not a factor. I almost never find the old style chargers unless it's with a calculator so I neglected to mention them but I FREQUENTLY find the newer style ones.

>The reason it was changed? People plugged the mains lead (the sort of
>lead used with cheap cassette recorders _and with some HP calculator
>chargers) straight into the HP97. That machine didn't like 110V or 240V
>across it. The results were, I am told, spectacular...

  ZOUNDS! I'll bet! Especially on 230 VAC!

>> frequently find these types of chargers in the surplus stores. I found so
>> many of them that I just quit them. FWIW the charger is not adaquete to
>> run the 97 without the battery however you can it off a decent power
>> supply connected to the battery terminals.
>Incidentally, there's a little circuit in the 97 (a couple of transistors
>and a resistor) to load down the output of the charger if the battery
>terminal voltage tries to rise about the 6.2V Vss line. This will happen
>if the battery is open-circuit or misisng.
>If you use a real HP charger, then it's safe to power it up with no
>battery installed (the HP charger has deliberately poor regulation
>characteristics). It'll normally work well enough to do calculations,
>although it won't print or read/write magnetic cards without a good
>battery installed IIRC.

   Sometimes they'll run without the battery but often they'll just set there and flicker. The printer and card reader will most definitely not work without a reasonably good battery (or a decent power supply) installed.

   IIRC there is NO regulation in either of these chargers.


Received on Thu Mar 28 2002 - 19:11:52 GMT

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