It's the ultimate in simplicity - I'm sure there are better ways to do it, but it's cheap and probably good enough for what I need. Cheers for the comment kyeong su shin
Well done getting it going again! I have a 1968 Facit 1125 that has one of those push button power switches and it doesn't work, so I might also need to replace it with a more modern switch. I have repaired a few vintage calculators and have also found some broken reed switches, quite unexpected!
Hi Pieter, I bet your 1968 1125 is a nice machine, I'm pretty impressed with the Hitachi made stuff (I should have read your message properly before I first replied, I thought you were talking about a 1968 Friden calculator not a Facit. The Facit, as you correctly pointed out, was made by Sharp - silly me!!!). Maybe those push button power switches weren't quite up to the job, although you can bet that these machines were used heavily when they were new - no one would spend that much money only to leave the thig sitting unused on the desk, so maybe the switch was just a little bit underrated for the amount of use it would end up getting. Perhaps the same applies to the reed switch - I should really get a magnifying glass onto it, just to see if I can understand what went wrong - only out of interest of course, because I've already replaced it and the calculator is back working. They are rather fun old things to work on aren't they. Cheers for watching.
@@GrumpyTim I love working on these vintage calculators! I had a look at the faulty reed switches under a microscope and it seems like they actuate, but doesn't make contact. So it must be some kind of oxidation or something that took place inside. My oldest Hitachi is a Hitachi KK 42 from 1971. It isn't pretty with the black keys and black case, but it does have nixie tubes!
@@GrumpyTim The Facit 1125 (Made by Sharp) is big and heavy, and incredibly complicated inside. It is unresponsive and I don't even know where to start looking for a fault. It uses magnetic core memory which makes it a really special machine.
Hi Pieter, oxidisation would make sense - I wonder if you could clean it using low current, high voltage - probably not. Or maybe putting a magnet on a motor so you could rapidly open and close the contacts to wear away the oxidisation - again probably not, and also there's little point because they're easy enough to replace, I just like to try simply out of curiosity. I just had a look at a photo of the KK42, maybe not the most gorgeous calculator ever, but not that bad either, and Nixie tubes can make any device look pretty!
Hi Pieter, I don't know what I was thinking when I sent my first reply - you put "Facit" and I must have only looked at the "F" and thought you were talking about a Friden - silly me!!!! I'm paying proper attention now, your Facit 1125 will be a lovely machine - I can't offer any advice for fixing it other than my usual approach, which is to look over the whole machine for the obvious, like a clearly blown component, or failed connection (these can be pretty invisible if it's a problem on a PCB track). I try to learn as much as I can, and then check things like voltages coming out of the power supply (or, as in the case of the calculator in this video, I just removed and checked some components that I expected to be faulty, replacing them as I went along). An oscilloscope can be really helpful when trying to find out what is and what isn't working, but you do want the machine you're operating on to be powered from an isolated mains supply, otherwise there can be many perils. You probably already know this stuff, I'm just scribbling down my thoughts as they come into my head.
Wonderful calculator, Tim! As the mechanical calculators were built to serve and last for two or three decades, I think they build those early electronic calculators with thing in mind. Definitely not a throwaway product. Those reed switch keyboards are the best! Your Tesla coil is interesting. Can you tell a little bit about this?
Yeah, they built them properly back then - no one had heard of a "spudger" back then - I had to take a mobile phone apart this week - arrrrrggghhhh!!!! The Tesla coil was a present from my brother - if you search on ebay for a "mini tesla coil" you should see plenty of things that look like my one - they're usually in kit form, but it's such a simple build you could probably do it with your eyes closed. There seem to be two versions, one has an audio input so you can play sound - I don't think that one is worth going for, because it won't sound that great at all, so I'd recommend the basic version like I have. It runs off a 9 volt supply - might even be 9 - 12 volts if I remember correctly, but I had a spare 9 volt supply so that's what I use. It has a tiny little arc that should just about be visible on the video - if you move a neon or a CFL (compact fluorescent lamp) near to it, both will illuminate. I read somewhere, that technically it isn't a Tesla coil because a true Tesla coil has a spark gap somewhere in the circuit, but I think we can live with the slightly innaccurate title for the time being.
Hi ohjajohh, it's educational for me too - until I've opened each machine, I won't have any idea what's inside or what could be wrong with it, so I'm learning as I make the video - definitely more fun that way. Cheers for watching.
Ah ha, he's a real star!!! I can't promise his level of intrigue and excitement, it'll be a bit more subdued over here, but thanks so much for subscribing Benspeed.
Cheers Ben, yeah, I suspect it would have run straight out of the box (albeit without the clear key and memory light) - pretty amazing that they can be that unloved and dirty yet still function. It's bizarre that I waited a few years to find a nixie tube calculator at a reasonable price, then two came along almost at the same time, but isn't that always the way!
I love these older Nixies where you can actually see the progression of the calculation where the tubes stay active. Any chance of doing your 355/113 in slo-mo?
Hi Rubbersawn, I've filmed a slo mo division for part 2 - it wasn't the 355/113 but it should do the trick. My camera doesn't have a particularly high frame rate, so I think that will be the limiting factor in the quality of the slo mo - I haven't reviewed that bit of footage yet, but hopefully it'll be vaguely interesting.
I've got no interest in ancient electronics other than the Battlestar Galactica aesthetic but your edits and commentary are so bloody good I'm in suspense wondering if you'll get the clear button working.
I'm definitely more at home working on mechanical stuff, but I do like some of the old electronic equipment like this, and more often than not the problems are relatively obvious, such as corroded tracks due to someone spilling coke in the keyboard or a loose connection and so on. You wouldn't think my commentary was good if you could see the virtual cutting room floor littered with endless outtakes as I attempt to say a sentence that would be easy if the recorder wasn't running - I really struggle doing the talking, it just doesn't come naturally at all.
