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twoweims · 06-24-2019, 10:45 PM

Has anyone come up with a suitable replacement for broken battery terminals?
I recently acquired another HP-67 with a broken terminal. I was able to solder a JST connector onto the broken stub so I could use a 1000 mAh LiPo battery. I would like to restore it to as close to original as I can. Thanks in advance for any advice.

Peter Monta · 06-25-2019, 12:19 AM

I'm not sure what the original material was, but it's likely to be one of the springy copper alloys like phosphor bronze or beryllium-copper. For reproduction I'd suggest phosphor bronze, since there are some possible hazards associated with fabricating beryllium-copper.

You'll also need to plate with a nickel barrier layer and then gold, perhaps the "hard gold" variant. Best to use a commercial service for that.

In low volume the initial shape can be made by cutting a strip of material and peening it to shape over a steel form to make that rounded-over contact tip. Leave some extra length for the plating connection.

Mark Hardman · 06-29-2019, 06:37 PM

(06-24-2019 10:45 PM)twoweims Wrote: Has anyone come up with a suitable replacement for broken battery terminals?
I recently acquired another HP-67 with a broken terminal. I was able to solder a JST connector onto the broken stub so I could use a 1000 mAh LiPo battery. I would like to restore it to as close to original as I can. Thanks in advance for any advice.

One of the best sources I've found is from the battery bay of the 82143A thermal printer. These printers can frequently be found on eBay for a song. Better yet, you can extract the entire battery terminal which greatly simplifies installation on the classic.

twoweims · 06-29-2019, 08:42 PM

Great Idea. Thanks.
I had no Idea these had the same battery terminals.
I will keep an eye out for one.

(06-29-2019 06:37 PM)Mark Hardman Wrote:
(06-24-2019 10:45 PM)twoweims Wrote: Has anyone come up with a suitable replacement for broken battery terminals?
I recently acquired another HP-67 with a broken terminal. I was able to solder a JST connector onto the broken stub so I could use a 1000 mAh LiPo battery. I would like to restore it to as close to original as I can. Thanks in advance for any advice.

One of the best sources I've found is from the battery bay of the 82143A thermal printer. These printers can frequently be found on eBay for a song. Better yet, you can extract the entire battery terminal which greatly simplifies installation on the classic.