HP 3785A Jitter Analyser Battery Replacement

[Simon_RL]

I am trying to get a HP 3785A up and running. There's not much wrong with it that can't be easily fixed. My biggest problem is finding a replacement battery. It is an AA (I think) 3.6v 100mah rechargeable (see photos below). It has a code on the side 1420-0282, which I have tried searching but no luck. There is also a link below to a tear down by Dave of the same device, @ 23:47 you can see the battery and board it is on.

I have also spent hours searching for a user and service manual, both the web and here on the forums. I have also followed the many links provided here on the forum to user/service manual download site and not had any luck either. My biggest issue is I don’t know the battery chemistry, while I am guessing it is alkaline given the age of the device, but I am no expert when it comes to batteries and don’t want to replace with the wrong chemistry.

All help very is much appreciated on either replacement battery or service manual.

[wn1fju]

My guess is that it is a NiCd battery.  All my HP pieces of that vintage that had rechargeable batteries inside were NiCd.  Presumably the battery is used to provide voltage to the RAM to hold settings, etc. 

I don't particularly like NiCds in these old pieces for two reasons:  1) they eventually leak, 2) I never use the piece enough to keep them recharged.

What I usually do is substitute regular alkaline batteries.  If there is suitable space, I put two AA (or AAA) batteries in one of those cheap plastic covered holders (so when they also leak, the stuff is contained) and put a Schottky diode in series (to prevent charging).  Never had a problem doing that.

[Simon_RL]

My guess is that it is a NiCd battery.  All my HP pieces of that vintage that had rechargeable batteries inside were NiCd.  Presumably the battery is used to provide voltage to the RAM to hold settings, etc. 

I don't particularly like NiCds in these old pieces for two reasons:  1) they eventually leak, 2) I never use the piece enough to keep them recharged.

What I usually do is substitute regular alkaline batteries.  If there is suitable space, I put two AA (or AAA) batteries in one of those cheap plastic covered holders (so when they also leak, the stuff is contained) and put a Schottky diode in series (to prevent charging).  Never had a problem doing that.

Thanks Heaps wn1fju, that is exactly the info I was looking for