Tek 453 transformer repurpose? - Page 1
Forum section: electronics / projects

author: liquibyte
author_rank: Frequent Contributor
timestamp: March 23, 2016, 08:48:34 pm
content: I have an old Tek 453 scope that I parted out due to there being much corrosion inside of it and too far gone to really try and save.After much confusing manual searching I finally figured out the wiring on the 120-0649-00 transformer. There are differing schematics when it comes to the transformer in these. Some show a 6 lead primary and some show an 8 lead primary (mine is. The fun part comes when trying to figure out the secondaries. I've seen at least 3 versions of this and to be honest am not sure why it was changed so much but the fun part of my journey comes with the fact that although I have an 8 lead primary, my secondaries are from a 6 lead version and not the 8 lead schematics I've seen.So, what I have is five secondaries. I've hooked it up and measured things to get the voltages to see what I have to work with.21-22 is 7.36V12-13 is 19.22V10-11 is 20.51V14-15 is 97.4VThe next bit is a winding with 3 taps. 16-17-18-19-2016-20 is 153.6V16-18 and 18-20 are 76.8V16-17 and 19-20 are 12.8V17-18 and 18-19 are 64VI'm not an audio type by any means so building an amp is unlikely. I'm sure that the first three secondaries can handle a couple amps each and the last two are in the 10's to 100's of mA range although I don't know what they would be exactly. What I have looks exactly like the two pics I've attached from an ebay listing with the only difference being that the primary wires are black, white, orange, blue and yellow, grey, red, purple, no grey with stripes. I've got it hooked up on the medium range in parallel, so red-black and yellow-orange because I run right at 122V out of the wall.I guess my question is what would you do with this? Some sort of power supply perhaps? Would it be possible to use secondary transformers off the high voltage secondaries to get lower voltages and higher amps and use them that way?

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 24, 2016, 07:32:57 am
content: Damn it. I would have taken that off your hands as my cat pissed in my tek 453 and blew out the transformer. Scope was stripped and chucked in the end.

author: med6753
author_rank: Super Contributor
timestamp: March 24, 2016, 01:17:49 pm
content: Here's a thought. If you don't already have one make an Isolation Transformer. You have plenty of taps to cobble together something around 120 VAC. You would have to experiment to see how much current you could draw before causing excessive sag or overload.This is something I put together using some surplus transformers. The one with the 102 VAC tap was out of an audio amplifier. The one with multiple taps was filament voltages from some unknown vacuum tube equipment.Just be aware that there are cautions to observe when using an isolation transformer with grounded equipment. There's a youtube video out there explaining that.

author: liquibyte
author_rank: Frequent Contributor
timestamp: March 24, 2016, 06:17:45 pm
content: Quote from: MrSlack on March 24, 2016, 07:32:57 amI imagine that the shipping on it would be not insignificant. I haven't weighed it but it's a couple of pounds at least.Quote from: med6753 on March 24, 2016, 01:17:49 pmThat's something I may consider although I've never really had a need for one, at least so far. I've been thinking about getting a variac but really haven't had much of a need for that either.I've been mulling things over and I think I could get 5 useful voltages out of it for low voltage DC. 21-22, 12-13, and 10-11 are obvious and would yield useful currents too. I was thinking 16-17 and 19-20 could be used as independent + and - low current supplies for powering op amps and the like.I've never messed with anything over 30V DC so I'm not sure about the other higher voltages and taps. I figured someone here might have done something with one of these before and have suggestions or ideas about it. I know the older scope transformers lend themselves to amplifiers and such but I think I read somewhere that this particular model wasn't suited very well for that due to something not working out right with the sound or distortion or something. I don't do audio so it's not really an issue for me. Oddly enough, I play guitar a little.Some of the older scopes have quite a bit of information about their transformer capabilities and a few of the newer ones do as well but this particular one is not easily searchable about it's ratings. I've got the voltages but no idea on the currents other than what you suggested for figuring out the sag. I'm not even sure how I'd go about testing that to be honest.