Tektronix 516 - more vintage Tek for the herd of gear. - Page 1
Forum section: electronics / testgear

author: Cubdriver
author_rank: Unknown
timestamp: May 14, 2017, 07:08:49 am
content: Hi all -I got my hands on a Tek 516 15 MHz dual trace scope today. It's been at least partially restored (the inside is quite clean, and the cabinet was repainted (unfortunately it's not an exact color match, and the lettering on the back was painted over, but...)It still needs a good brushing and blowing out, and to have an internal conduit that is misrouted reinstalled, but physically is in excellent condition. Electrically, it has nice clean traces, but the triggering circuit does not seem to be working, so there will be some troubleshooting involved there. Fortunately, a good scan of the manual was found on tekwiki, courtesy of BAMA.The fuzzy trace image is due to the triggering issue.A few more photos are at:https://pmanning.smugmug.com/Electronics/Tektronix-516-15-MHz-Dual-Trace-Oscilloscope-Pat

author: Martin.M
author_rank: Frequent Contributor
timestamp: May 14, 2017, 07:18:41 am
content: looks very nice,seems to be the 2 channels version of 515A, not so oftenly to find.greetingsMartin

author: Cubdriver
author_rank: Unknown
timestamp: May 14, 2017, 07:34:41 am
content: Quote from: Martin.M on May 14, 2017, 07:18:41 amHi Martin!Yes, based on what I've read in the Stan Griffiths book on the old Tek scopes and on Tekwiki that's pretty much exactly what it is, though with a slightly different front end than the 515A. With luck, the triggering issue won't be too much to sort out. I'll post findings when I look at it further.-Pat

author: Martin.M
author_rank: Frequent Contributor
timestamp: May 14, 2017, 08:30:58 am
content: its mostly the same with our oldiescheck all voltages from PSUget one 6DJ8 (E88CC, CV2492, CV2493, Cca) from anywhere and test by swapping, V24 + 45greetingsMartin

author: med6753
author_rank: Super Contributor
timestamp: May 14, 2017, 08:37:51 am
content: Nice scope, I'm jealous!I also have a copy of Stan Griffith's book. It doesn't mention it but is it possible that it uses tunnel diode triggering like the 547? Although I doubt it since it's only 15MHz bandwidth. Those tunnel diodes can be had to find if bad. Here's some info that could be helpful if it does...http://www.reprise.com/host/tektronix/reference/tunnel_diode.asp

author: Martin.M
author_rank: Frequent Contributor
timestamp: May 14, 2017, 07:16:08 pm
content: 515 (and this 516) are old Scopes, made in the late fifties.So I think they use a Miller integrator there, not TD. Mostly this problems can be catched by swapping tubes, a tired 6DJ8 in the trigger is more then possible.If I see that right the use of tunneldiodes was beginning in the 33 MHz series, 541, 543,545, 555 and all later scopes (50MHz) 547, 556, also in the 549 storage.greetingsMartin

author: David Hess
author_rank: Super Contributor
timestamp: May 15, 2017, 01:08:37 am
content: No tunnel diodes in this one or at least I did not see any in the schematics.The internal trigger is only taken off at the vertical CRT amplifier so triggering in dual trace mode will be a little funky. Test it with one trace displayed or the external trigger.