Telequipment D61a - Page 1
Forum section: electronics / testgear

author: Thilo78
author_rank: Regular Contributor
timestamp: April 10, 2016, 01:14:10 pm
content: At saturday's hamfest/boot sale I got a few items for my lab.This is number one:A Telequipment D61a scope, 1970s vintage.Its outer appearance is near mint, with but a few scratches and some dust.Today, I ran through the calibration procedure and now have it reasonably adjusted for its duty.In the process I found that the board layout is somewhat wrong in the service manual, as the adjustments for the zero line through the vertical deflection settings are not on the board itself, but on the input attenuator boards.So some fiddling is required in the process.I'm quite happy with this unitTwo caveats:1. The unit is really long, given its width and height. You will need space to accommodate the case.2. There's no trace rotation adjustment. Instead, there is a plastic bracket protruding through the back of the case, which allows you to physically rotate the tube.

author: MrSlack
author_rank: Frequent Contributor
timestamp: April 10, 2016, 01:21:58 pm
content: Nice. I had one of them in the 1990s. Paid £5 for it at a car boot sale.Complete sods to repair though as the board inside is pretty much rat's nest at the front end from what I remember. I think I eviscerated it for parts for sometime else in the end and then unceremoniously dumped its corpse at the tip.

author: Thilo78
author_rank: Regular Contributor
timestamp: April 10, 2016, 01:31:00 pm
content: Funny thing is, that it can't deny its relation to Tektronix.The knobs have the same shape and the same feel to them. But they're black instead of grey or beige.The board isn't too bad. Only the wiring is a little "point to point" style.All in all the whole assembly is really tidy, and you can access the component side from the right, the solder side from the left.Really nice to work in. (In fact so nice, that I totally forgot to take pics)Only problem is that you're looking for certain pots and find their places unpopulated.Luckily I found those after checking the input circuits.

author: MrSlack
author_rank: Frequent Contributor
timestamp: April 10, 2016, 01:48:08 pm
content: Tek did indeed own them I understand. The D75/D83 are similar in construction to some Tek 7000 plugins as well I noticed when I took one of them to bits for repair (D83).Mine was a mess. I'm wondering if it was a different hardware revision.

author: tautech
author_rank: Super Contributor
timestamp: April 11, 2016, 07:31:48 am
content: Quote from: MrSlack on April 10, 2016, 01:48:08 pmYes, but when TQ was producing the D61A, I'm not sure.A D83 was my first scope and as you say they did have plugins that made them quite easy to work on IF you had an extender cable which weren't at all difficult to make.The D83 manual does list Telequipment as a division of Tektronix UK, of earlier models I'm unsure.Anyways, congrats Thilo78, she's a very tidy unit.

author: MrSlack
author_rank: Frequent Contributor
timestamp: April 11, 2016, 08:27:43 am
content: Talking of which, there is a smaller brother of the D83, the D75 (smaller tube, same plugins) on gumtree in the UK at the moment:https://www.gumtree.com/p/other-miscellaneous-goods/oscilloscope-telequipment-d75-/1163434064Slightly tempted but it means going to Sarfeeend and the time/div knob has disintegrated.

author: tggzzz
author_rank: Super Contributor
timestamp: April 11, 2016, 07:55:30 pm
content: Quote from: MrSlack on April 11, 2016, 08:27:43 amOr, 20 miles norf of there you could find something probably more interesting... fleabay item 152045606375

author: MrSlack
author_rank: Frequent Contributor
timestamp: April 11, 2016, 09:50:27 pm
content: Ooooooh a 453 was my daily driver for a few years. Until the cat pissed in it.Tempted by that as it's about a 20 min drive from my father's. Thanks for the heads up. Everyone else hands offProbably worth it for the working FETs and tunnel diodes - worth a small fortune!

author: tggzzz
author_rank: Super Contributor
timestamp: April 11, 2016, 10:00:57 pm
content: Quote from: MrSlack on April 11, 2016, 09:50:27 pmAnd that's why I didn't post the obvious URL