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Battery for PS/2 P70

kobayashimaru

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Joined
Aug 21, 2015
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23
Location
Jackson, New Jersey
Greetings!

I have a IBM PS/2 P70 386 on the way and I'm going to have to replace the CMOS battery. Anybody know what kind or part number? I'd like to order it ahead of time. I'm also not averse to making one if necessary.

I'm also going to have the fun of repairing the floppy drive, but I've read up on that pretty well

Thanks!
Joe
 
Reviving a dead thread. These camera batteries; are they still the only option for P70's? After having dealt with battery leakage repairs I am extremely hesitant to put these back into machines in 2024.
It's just a 6V non-rechargeable battery, so with some cutting and soldering, you might have the option of running a lead to outside of the computer, with pretty much, any 6V non-rechargeable battery (or battery pack) at the cable end.
 
It's just a 6V non-rechargeable battery, so with some cutting and soldering, you might have the option of running a lead to outside of the computer, with pretty much, any 6V non-rechargeable battery (or battery pack) at the cable end.
so if its non rechargeable (I assumed it was a rechargeable battery) Cant I use a couple CR2032 cells in series?
 
so if its non rechargeable (I assumed it was a rechargeable battery) ...
"Lithium", so non-rechargeable.

Cant I use a couple CR2032 cells in series?
Possibly. When batteries are new (or fully charged in the case of rechargeables), they measure something over the nominal voltage. So a question becomes, is the amount-of-voltage-more-than-nominal-value going to be a problem for the particular equipment? For example, I just now measured a new CR2032 battery. It measures 3.3V, so is 6.6V going to be an over-voltage problem for the P70? I don't know. Maybe the IBM supplied 6V battery was just as high when it was new. If you feel uncomfortable about the situation, you could put in a 1N4148 diode in series to knock the voltage down a little.
 
"Lithium", so non-rechargeable.


Possibly. When batteries are new (or fully charged in the case of rechargeables), they measure something over the nominal voltage. So a question becomes, is the amount-of-voltage-more-than-nominal-value going to be a problem for the particular equipment? For example, I just now measured a new CR2032 battery. It measures 3.3V, so is 6.6V going to be an over-voltage problem for the P70? I don't know. Maybe the IBM supplied 6V battery was just as high when it was new. If you feel uncomfortable about the situation, you could put in a 1N4148 diode in series to knock the voltage down a little.
Unfortunately I used my last 1n4148 and tried using some 1n270's but that pretty much lost all the voltage. I just put in an order for some 1n4148 diodes. Thank you for the input! This is good news!
 
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Yes. Went over it several times. I ended up gettting less than 1v. But ordered new diodes so will go over them again.
 
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Just chiming in, I have 3 PS/2 (2 Model 50Z and a 70) wth that 72X8498 original battery from the 80s, all dead, non of them have shown any sign of leakage, so probably it is not a concern? I don't know how it positioned in P70 but in others its even outside of the main PCB area. Did anyone seen that battery leaked?
 
Just chiming in, I have 3 PS/2 (2 Model 50Z and a 70) wth that 72X8498 original battery from the 80s, all dead, non of them have shown any sign of leakage, so probably it is not a concern? I don't know how it positioned in P70 but in others its even outside of the main PCB area. Did anyone seen that battery leaked?
On the portable P70 the battery is literally right on the top of thr system above the mainboard. If it was to leak it would leak down the entire length of thr system bosrd including cou, fpu, and ram. I have seen the same or similar batteries destroy the 5170 and cameras. So not willing to risk it.
 
I understand, probably it would be easier to get this battery from Amazon and just make some leads outside, so it has zero chances of wrecking havoc with incorrect current/voltage/leackage?
 
I understand, probably it would be easier to get this battery from Amazon and just make some leads outside, so it has zero chances of wrecking havoc with incorrect current/voltage/leackage?
That would look terrible.

So my leads I bought online came in: https://www.ebay.com/itm/254628295576

I measured the voltage and was getting 6.1V. I decided not to use a diode as I figured it would be closer to 6.4V and it wasnt. I connected it up. Changed the settings, Date and Time. Powered it down and unplugged it for 40 minutes. And when I boot it back up the settings retained. Seems to work fine.
 
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