HP 97 advice please !


I recently bought an HP-97 w/AC adapter at a city auction.
When plugged in, only the small red dot on the upper left-ish side of the display lights and only very faintly. (I think it's the 'on' light). It doesn't have a battery pack but my understanding is that it runs the printer, not the calculator.
Any ideas about what could be wrong and how I can fix it myself?


You really need a battery pack in GOOD condition to run the calculator. AC only can dammage the calculator and/or prevent the calculator to turn on or work correctly.

You can try a direct well filtered voltage on the contacts in the battery compartment (respect the polarity!!!) to try the calculator "safely" (don't plug the adaptor in this case)

Give us some news!



What is direct well filtered voltage?



I think what Michel is saying is to provide DC that is the correct polarity and voltage, with pure DC ("well filtered"). The issue is that most power supplies do not provide clean DC--there is a fluctuating voltage which can damage the electronics.

So, you need a good voltmeter, some batteries in holders, alligator clips, and a source of variable reistance. With these things, you can make pure DC from primary cell batteries, and use the variable resistance to get the vlotage just right.




As already mentioned, you need a good battery to run this calculator properly. Fortunately, the batteries (82033A) are fairly easy to find, because they are the same as are used for the 41C family printers, tape drives, etc., and they can be readily rebuilt with sub-C size NiCd batteries.

However, do you have the battery door for the calc? Sometimes these calcs lose that door, so that would be a bigger problem.


I do have the battery door and the contacts are corrosion-free.
I read somewhere on this site that it's possible to get tabbed batteries at radio shack and put them together to run calcs. If that's so, is there anything I should know before I try this or should I buy a ready-made pack? Besides e-bay where is the best place to buy a ready-made pack?


Absolutely make sure you never run the calc off the AC without a battery. Turning on the printer will destroy it!

You could get Batteries Plus to put together a battery pack following polarities in this web site.

Or buy an old one off Ebay or the like...


You need a good battery pack to run the machine. Easiest place to get one if you do not have an old one to rebuild is from Mark Hoskins. He sells them on EBay (id WATERHOSKO) for around $30.


I second the feedback Dave gave you about the batteries availavle from Mark Hoskins. I'm very happy with the ones I purchased from him for my printer and tape drives. He currently has them offered on eBay for $27.00 USD + $4.00 S&H --- See http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3084159287&category=11713


So, you are saying this is normal for the calc NOT to operate with only the AC plugged in and no battery pack and the calc MUST have a battery pack (good one) to operate?

Just trying to get clear because I don't want to spend $ on a battery pack if the calc is faulty. With the AC plugged in, the calc will only faintly display the low battery indicator light on the display.



Please, do not run it on the AC adaptor any more! You have to have a good battery in there to smooth out the voltage.




Another thing you can try, if you don't want to just buy a battery pack without knowing if the calc still works, is to say which city you are in. There is probably someone here that lives near you who has a working battery of that type, and you could just go on over and try it out.


I found that there is a Batteries Plus just a few miles from my house and they said they'll put a pack in the calc to determine it's condition before I purchase a pack !
How great is that!!!!!!!!!

Just so you all know, I haven't actually been running it from the AC, just plugged it in to see if it would power on but won't do it again. Thanks for all your advice and I'll let you know what happens.

I had one of these calcs 24 years ago where I worked. When I left the company, I wanted to take it with me soooo badly, but it wasn't mine, belonged to the company. I haven't had an affection for a calc since then (I wondered why I loved it so much!?, was that weird, oh well. I moved on.)

12 years later, I found an HP 41C that someone had tossed when cleaning out a desk/office, I guess. I kept it for years not knowing what I'd ever do with it but, knew it couldn't just be thrown out, even though the batteries were bad and I didn't have any other way to power it up. Then I met someone who regularly sells on e-bay and he said, 'hey you could sell that on e-bay'. So, I look it up on e-bay and one of the ads told of the on-line HP Museum. Voila, I found that I wasn't weird to have loved my calc from 20 years ago!!! Then I saw one in an on-line city auction and bought it.

Isn't it funny the way things happen?



Welcome to the dark side of the force, young Vickie... there are 50 other models calling you... buy me, buy me, buy me...


Good one!

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