If the batteries are really as defective as we may believe, they would have self-discharged to 10% or less of original capacity in 35 years.The batteries in and of themselves do not seem to explode, it's that they explode when depleted.
Yes, when powered on, the RTC circuit is actually fed with 5V power, 3.6V will work perfectly fine.Question : the Soldered SE batteries are labeled 3v. Can you fit a 3.6v without causing harm? With my SE I fitted a socket but went to the trouble of buying a 3v version.
Still have the original, let me know if you are interested in more photos - under "Ord. No. 6126" it says "MH 13654 (N)" - I think that means it is Manganese Dioxide? Mine is date code 0188.Also, nice that you've found the Lithium Manganese Dioxide cells! Now I've looked at the photos in detail of the original VARTA battery I removed, indeed I see the original just says "3V". If indeed the original was also Lithium Manganese Dioxide chemistry, that's pretty nice!
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UPDATE: The original battery is labeled with "ER 1/2 AA Order Number 6126", which indicates Lithium Thionyl Chloride chemistry, looks like "3V" was merely an abbreviation of the true nominal voltage of 3.6V. This is the closest product number datasheet I could find.
http://products.varta-microbattery.com/applications/mb_data/documents/data_sheets/DS7126.pdf
My particular copy was lot number 0387... appears to be a code for date of manufacture March 1987.
I think so! I think it would be nice to be able to build these new boards with as many or few original parts as possible.would it be worth getting a few?
The pinout needs re-jigging, but it's used in a lot of other period correct machines (Acorn A3000 series), would it be worth getting a few? A simple PCB adapter is doable.
Can someone sanity-check me here please? L1 on the BoM is marked as 33 µH, but on the board I am taking bits off, it seems to be 21 µF (apologies for poor colour reproduction)
View attachment 38733
Although in my photo it looks more like 27 or 28? Doesn't look brown...Thankyou!