Safely charging my 65

[Brad Barton]

Having possibly fried the ACT chip in one of my HP-97 I'm reluctant to plug my HP-65 directly into the wall charger. I'd like to find some way to externally charge the battery.

I saw a thread by Geoff Quickfall mentioning that he was able to charge the batteries in his Classic calculator with one of the external HP-97 chargers. I have an external charger for the 97, but the "blades" don't line up with the pads on the 65 battery. I could make some modifications, but I don't know for sure how the polarity is laid out.

Does anyone know a safe, reliable way to externally charge HP-65 batteries?

[Don Shepherd]

(03-21-2015 02:32 AM)Brad Barton Wrote:  Having possibly fried the ACT chip in one of my HP-97 I'm reluctant to plug my HP-65 directly into the wall charger. I'd like to find some way to externally charge the battery.

I saw a thread by Geoff Quickfall mentioning that he was able to charge the batteries in his Classic calculator with one of the external HP-97 chargers. I have an external charger for the 97, but the "blades" don't line up with the pads on the 65 battery. I could make some modifications, but I don't know for sure how the polarity is laid out.

Does anyone know a safe, reliable way to externally charge HP-65 batteries?

Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.

[TASP]

Y'all see how nice that external HP 35/45/65 charger is ?

Then I look at my HP92266 charger, and it is just sad. I admit, the 92266 has a charming clunky third party vendor feel, but really now, is that appropriate on something with an HP model # ??

[rprosperi]

(03-21-2015 03:05 AM)Don Shepherd Wrote:  Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.

The charger that Don suggests works very well, I fully endorse getting one. BTW, this one is rather expensive, you can get them much cheaper if you can wait and watch auction sites, flea markets, CL, etc.

HP made external chargers like this for:

* Classic series batteries (this one) - common
* TopCat batteries (9x desktop calcs, 82143A Printer, 82162A Printer, 82161A Tape Drive) - less common
* Spice calculators - rare - no idea why; guess they didn't sell well
* Woodstock calculators - less common

I have and use all of them. They provide the dual advantage of charging a 2nd battery while using another, but much more importantly it prevents damage to the valuable calculator should the aging battery fail or leak during unattended charging.

Recommended!

[Don Shepherd]

(03-21-2015 12:20 PM)rprosperi Wrote:  

(03-21-2015 03:05 AM)Don Shepherd Wrote:  Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.

The charger that Don suggests works very well, I fully endorse getting one. BTW, this one is rather expensive, you can get them much cheaper if you can wait and watch auction sites, flea markets, CL, etc.

HP made external chargers like this for:

* Classic series batteries (this one) - common
* TopCat batteries (9x desktop calcs, 82143A Printer, 82162A Printer, 82161A Tape Drive) - less common
* Spice calculators - rare - no idea why; guess they didn't sell well
* Woodstock calculators - less common

I have and use all of them. They provide the dual advantage of charging a 2nd battery while using another, but much more importantly it prevents damage to the valuable calculator should the aging battery fail or leak during unattended charging.

Recommended!

Thanks Bob. I'll have to consider getting one of these too. Sounds like a pretty good insurance policy for a very valuable commodity.

[Brad Barton]

(03-21-2015 12:20 PM)rprosperi Wrote:  

(03-21-2015 03:05 AM)Don Shepherd Wrote:  Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.

The charger that Don suggests works very well, I fully endorse getting one. BTW, this one is rather expensive, you can get them much cheaper if you can wait and watch auction sites, flea markets, CL, etc.

HP made external chargers like this for:

* Classic series batteries (this one) - common
* TopCat batteries (9x desktop calcs, 82143A Printer, 82162A Printer, 82161A Tape Drive) - less common
* Spice calculators - rare - no idea why; guess they didn't sell well
* Woodstock calculators - less common

I have and use all of them. They provide the dual advantage of charging a 2nd battery while using another, but much more importantly it prevents damage to the valuable calculator should the aging battery fail or leak during unattended charging.

Recommended!

Thanks guys. I'll keep my eyes peeled for a 92266.

Brad

[TASP]

Let me extend and revise my post;

the 92266 is a 4 cell N charger. For the HP41C/CV/CX.

And even though they have an 'official' HP model #, they just don't have that HP finesse.

I'm using mine to charge some NiMH now. Looks like it is a 3 day process . . .

Glad I ordered several sets.





Addenda:
Just went looking, and found HP offered the N charger in 1986 for $39.95. I can't imagine I paid that much for mine. LOL !! I do like having the charger base directly take N cells, and only N cells. Don't need a sleeve to make the cells fit in a AAA machine. And I might update the charger electronics at some point.

[PANAMATIK]

(03-21-2015 02:32 AM)Brad Barton Wrote:  Having possibly fried the ACT chip in one of my HP-97 ....

I cannot give advice for charging more than others have given you already. I agree that you can safely charge the batteries inside any woodstock calculator if the calculator is switched off.

But you can repair your fried HP-97! Although the new ACT is not suitable directly for the HP67/HP-97 it can be used to replace an HP21/HP-25 and use the original ACT in the HP-97s. All you have to do is buying a working HP-25/HP-25C and replacing its ACT.

I tried an HP-25C ACT in my HP-97 and everything including printer is working fine. Unfortunately the card reader of my HP-97 was not yet repaired, so I couldn't test it, but I assume that it should also do well with any ACT.

If replacing the HP-97 ACT you should know, that even with a low profile socket there is not enough space inside the case, it must be soldered directly.

Bernhard

[Brad Barton]

Oh I see, I've misunderstood. The 92266 is for rechargeable N cells.

Don mentioned that he's never had any trouble as long as he doesn't turn on the 65 without the battery pack installed. I wonder what would happen in the case of plugging in the charger with a faulty battery pack.

I'd never want to turn the unit on while charging, in case the battery pack was bad, but I'm unclear as to whether attempting a charge with a faulty pack is dangerous. I think my battery pack is OK, but hesitate to take a chance on damaging the 65. If you guys say it's OK, I'll go for it. I miss playing with the little bugger.

(03-22-2015 08:13 AM)PANAMATIK Wrote:  I cannot give advice for charging more than others have given you already. I agree that you can safely charge the batteries inside any woodstock calculator if the calculator is switched off.

But you can repair your fried HP-97! Although the new ACT is not suitable directly for the HP67/HP-97 it can be used to replace an HP21/HP-25 and use the original ACT in the HP-97s. All you have to do is buying a working HP-25/HP-25C and replacing its ACT.

I tried an HP-25C ACT in my HP-97 and everything including printer is working fine. Unfortunately the card reader of my HP-97 was not yet repaired, so I couldn't test it, but I assume that it should also do well with any ACT.

If replacing the HP-97 ACT you should know, that even with a low profile socket there is not enough space inside the case, it must be soldered directly.

Bernhard

Bernhard, thanks for the great idea. Before I go down that path I need to find out if the ACT in my 97 is definitely the problem. One member generously offered to help me diagnose it, but I haven't had the time to disassemble it and work through the process.

If I find out that the ACT is indeed the problem, you've illuminated a path to fixing the problem, because I happen to have a working HP-25 in my collection.

Brad

[Don Shepherd]

Brad, here is how I operate my 65.

I got a battery pack on Ebay 2 or 3 years ago to replace one I got about 6 or 7 years ago. I had no indication that the older one was bad, but I thought it is probably a good idea to get a new pack every few years.

I generally operate my 65 from the battery pack. When I notice the decimal points all stay on (indicating low battery charge), I get out my AC adapter and plug it into the calc and let it charge for maybe 10 or 12 hours. I usually don't use the calc while it is charging, but on occasion I have and it worked fine. After 10 or 12 hours I unplug the calc from the AC adapter and run it off the newly charged batteries, and it has always worked fine. Since I only use it irregularly, I guess it probably runs a few months between charges.

Right, the one thing I would never do (based on what I have read from many others) is to operate it from the AC charger without the battery pack present in the calc.

The only "accident" I ever had with my 65 is when all of my standard pac magnetic cards could not be read one day, and I have a feeling that the pak got too close to a magnet somewhere (probably on the side of my filing cabinet). But another user told me the secret to re-recording the pak cards by tricking the 65 to think the card is unprotected, and that worked like a charm.

Don

[Les Bell]

(03-21-2015 03:05 AM)Don Shepherd Wrote:  Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.

That gadget isn't really a charger - it's a battery holder with the same socket as the calculator, allowing a spare battery to be recharged while another battery is in use in the calculator. It relies on the original charger to power it.

As far as I'm aware, the Classic chargers provided a regulated supply for the calculator in addition to a second connection to charge the battery. That's why the Classic battery socket has three pins plus a spring strip to reconnect the calculator circuitry to the battery when the charger is unplugged. So there really shouldn't be a risk to the calculator from charging the battery while it's in it. It was only the Woodstock series that applied a high voltage from the charger and required the battery to be present and connected in order to provide a load and drop the voltage. That's why the Woodstocks have so many problems with fried ACT chips - people plug them in and fire them up with the battery pack removed and blam!

Of course, as machines like the 65 get rarer and rarer, I'm of the opinion that any owner should do whatever makes them feel comfortable about keeping the units safe. Also, I'm going on memory here - my 65 was stolen in 1978 - so anyone with more recent experience with the Classics is welcome to step in and correct me.

[Brad Barton]

(03-24-2015 01:04 AM)Don Shepherd Wrote:  Brad, here is how I operate my 65.

I got a battery pack on Ebay 2 or 3 years ago to replace one I got about 6 or 7 years ago. I had no indication that the older one was bad, but I thought it is probably a good idea to get a new pack every few years.

I generally operate my 65 from the battery pack. When I notice the decimal points all stay on (indicating low battery charge), I get out my AC adapter and plug it into the calc and let it charge for maybe 10 or 12 hours. I usually don't use the calc while it is charging, but on occasion I have and it worked fine. After 10 or 12 hours I unplug the calc from the AC adapter and run it off the newly charged batteries, and it has always worked fine. Since I only use it irregularly, I guess it probably runs a few months between charges.

Right, the one thing I would never do (based on what I have read from many others) is to operate it from the AC charger without the battery pack present in the calc.

The only "accident" I ever had with my 65 is when all of my standard pac magnetic cards could not be read one day, and I have a feeling that the pak got too close to a magnet somewhere (probably on the side of my filing cabinet). But another user told me the secret to re-recording the pak cards by tricking the 65 to think the card is unprotected, and that worked like a charm.

Don

Don,

These details are very reassuring. Sorry if I sound paranoid. I just don't want to ruin the only 65 I'm likely to have by making a careless mistake with it.

Thanks,
Brad

[Brad Barton]

(03-24-2015 01:43 AM)Les Bell Wrote:  As far as I'm aware, the Classic chargers provided a regulated supply for the calculator in addition to a second connection to charge the battery. That's why the Classic battery socket has three pins plus a spring strip to reconnect the calculator circuitry to the battery when the charger is unplugged. So there really shouldn't be a risk to the calculator from charging the battery while it's in it.

This makes perfect sense to me. Now that you mention it, I can see the spring strip down in the charger socket.

Quote:Of course, as machines like the 65 get rarer and rarer, I'm of the opinion that any owner should do whatever makes them feel comfortable about keeping the units safe.

I agree completely, but I must say that I'm getting more comfortable since so many have kindly shared their knowledge.

Thanks,
Brad