Yeah, the battery contacts are a perennial problem; fortunately Keystone makes one others have said works as a replacement, and DigiKey carries it for 81¢ each: https://www.digikey.ca/en/products/detail/keystone-electronics/5209/299941
The J-clips are a bit of a bastard; I was "going to look through their stuff someday" for a similar enough clip I thought could be manhandled into a replacement.
DigiKey's Battery Holders Clips & Contacts Dept is full of interesting stuffs, BTW... a great place to look when you need to pad an order for free shipping: https://www.digikey.ca/en/products/filter/battery-holders-clips-contacts/86
Yes, I've tested mine; voltage does cause deflection and the movement is smooth and no binding, however a couple of the current shunts are extra crispy hand-wound-on-phenolic-formers type and I haven't tackled them yet, nor have I found anything I think might be a reasonable ceramic substitute.
I may bug you to take some readings on yours somewhere over the winter when I'm stuck inside with nothing to do however. I have yet to find a schematic on the 635; instead of the usual multiples-of-5 scale, it has a oddball scale in multiples-of-3, which I guess was due to some variation in the demands of local electrical code.
Good hunting!
HOLY SHEEIT!!! I actually found the post where I read about IMS ( www.multimeter.com ); they have an assortment of Simpson parts, including OEM-style copper-colored phosphor-bronze battery clip sets: https://www.metersales.com/shop/category/parts-for-test-equpment-138
mnem
Very interesting on the OEM battery clips. My original plan was to get a small piece of similar type metal from a hobby shop or something like that and try to craft the right shape with tin snips and then fold and drill as necessary so a drop in replacement is a heck of a lot easier for sure.
The 635 is an interesting piece of kit. Most of the ones I've seen pictures of are army surplus 635HV versions with the high voltage divider back. I know I've seen schematics for the high voltage back but I can't find them again right now.
The scales based on multiples of three threw me off at first and I thought maybe that was a government requirement since the vast majority of 635s I've seen pictures of out there are army surplus units as is the one I have. Of the pictures I've seen of these online of various 635s, I've never seen one where the Canadian Armed Services inventory plate's been stamped for navy or air force, they're all army, and I've only seen the occasional non-government surplus 635HV and only once seen a regular non-government, non-HV civilian 635 without the voltage range expander option.
However, looking around a bit more and adding the Triplett plus the Northern Electric meter that Bach-Simpson made, it looks like the AT&T Bell System standardized on the multiples of three scales and got carried over by Northern Electric up here, and the Triplett 630 which so far looks like a regular multimeter without any corporate or government affiliation or customization is also ranged in multiples of three so it looks like it's more common than I thought at first. One thought that did come to mind is that it does accommodate 6, 12 and 120V electrical systems easily but telephone's -48V so that doesn't explain the phone companies going for that sort of ranging unless it's to have nominal voltage land 4/5 up the 60 V scale in their case. I haven't posted the pictures because of the image SNAFU but when I tested out those two meters, I did 6 and 12 volts to get half scale and full scale deflection respectively instead of the 5 and 10 V that I did for the AVO and the 270.
Let me know if you do need any measurements from my 635. I haven't comprehensively tested it yet, just used it for some voltage measurements which it's been great for, so hopefully the battery leakage damage is limited to the one clip that got destroyed and hopefully none of the shunts or precision resistors got damaged. I did a cursory lookover after I finished scraping what was left of the government issue Canadian Forces batteries that were still in it into the garbage but I haven't done a comprehensive all functions, all ranges test yet even though I've been using it as a voltmeter for some things with no problem.