Tektronix 2215 SMPS - Page 1
Forum section: electronics / repair

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2021, 01:14:33 am
content: I evaluated a 2215 for a friend that he picked up for $10 at an antique flea market for function and to repair a "no power" condition.It was the power switch which I cleaned and lubed.All was good so I gave it back to him and it was working just fine.I showed him a few YouTube videos on how to do the basic stuff.A week later he says the power went out and it sounds like it's chirping.Of course it's in the SMPS.Many months go by because I had no time to get to it.Service manual already downloaded, I checked MANY things. The FET was fine, the loads have no shorts just 100Ω+ readings (all in spec from what I see here) but the supply was in shutdown.Now to the real issue, where is the circuit diagram for the A18 board!!!For some reason, it is omitted form the PDF.So does anyone have the location of, or a copy of the A18 board so I can troubleshoot this thing that simply refuses to power up (no chirping) now? All I have is +/- 85V (chassis referenced) on the large filter cap.

author: pcwrangler
author_rank: Regular Contributor
timestamp: September 02, 2021, 01:33:35 am
content: On page 204 of svc manual. If yours doesn't have it it's in tek folder on xdevs.

author: bob91343
author_rank: Super Contributor
timestamp: September 02, 2021, 01:35:50 am
content: Don't most of those scopes use a 43 V power supply? So maybe substituting one could solve the problem. Most of those problems seem related to the SMPS.

author: pcwrangler
author_rank: Regular Contributor
timestamp: September 02, 2021, 01:42:46 am
content: If that one doesn't include it I know the one from tek does.https://www.tek.com/manual/2215

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2021, 01:47:26 am
content: I don't think it's there. If you know the page.....

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2021, 01:49:09 am
content: I had 2 perfectly brand new 24V Power One SMPS's but where are they nowI know about injecting power in but I can't seem to find the for a few months now....Quote from: bob91343 onTodayat 10:35:50

author: pcwrangler
author_rank: Regular Contributor
timestamp: September 02, 2021, 01:54:14 am
content: And here.https://w140.com/tek_2215_service.pdfPage 204

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2021, 01:59:13 am
content: Thanks that was quick. I've been looking for a few months now.Maybe my searches were sabotaged by Google cookies.....For future reference the schematic is on 207.

author: pcwrangler
author_rank: Regular Contributor
timestamp: September 02, 2021, 02:14:53 am
content: HTH. Tek made some major changes on later models, adding an extra board at least in one case. I remember reading about it in this forum but I don't remember where. Keep that in mind if yours doesn't match the schematic. I don't know if the updates even have a schematic. Good luck. Hope you get it fired back up.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2021, 02:30:32 am
content: Well I am I guess tired or old.I looked from the top to almost bottom in the manual I had and never seen a reference in the bookmarks to A18...so I never thought to look at the end of the PDF.Both of you clearly sent the correct links.My own overlooking the tail end of the document has wasted so much time.Tektronix's overlooking a proper bookmark format is on them.I decrypted the locked PDF's bookmarks and made 2 for the A18 board.When I have time, I'll fix the others.Thanks everyone for your help.I'll follow up I hope soon.....

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 09, 2021, 03:22:40 am
content: With 43V applied to the rest of the scope, it fired right up and worked properly.I used my previous lash up which was already in a cabinet, of a Variac and isolation transformer.I attached a bridge rectifier and a 470µF cap and adjusted to 40V unloaded.Regulation was poor and I had to crank it up under load to the nominal 43V specified.Now on to the SMPS repair.I basically lifted one leg of all the passives and checked them with the ubiquitous $20 LCR tester.The same tester was used on all the transistors and the SCR as well as the Zeners and other diodes.R911 the 150Ω 1 W carbon comp resistor was way out of tolerance along with R937 the 8K2 ½ W one as well.I've got some parts coming to fix the few items that have gone out of tolerance.I almost forgot R922 the 86K6 resistor is also out of range at 88K+The IRF820 will get swapped with something with a lower RDS on.The TL494 is also going away just because.That's all until pieces parts arrive.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 12, 2021, 12:53:51 am
content: It's Rifa madness day. I was double checking the Tektronix SMPS and look what I found. 2 Rifa caps so tiny you needed to magnify them (I have a x10 Diopter Bausch & Lomb Coddington) to see the cracking going on with its guts oozing out. The first photo includes the bad resistors and 4 bad caps.The second photo is of a brand new multi output Power One SMPS to try out the UTG signal generator in the other forum post, with clean power. More Rifa caps all cracked. It had never ever been used but it was NOS.....It was time to modernize both with some Y capacitors.https://www.amazon.com/Bausch-Lomb-Illuminated-Coddington-10x/dp/B0009PPT52