Another Newbie Tek 2213A Repair Attempt - Page 1
Forum section: electronics / repair

author: CuriousRambler
author_rank: Newbie
timestamp: March 14, 2025, 02:06:25 am
content: Well I haven't done anything with it in a handful of years, but just discovered my 2213A won't be doing any work without some attention. I'm just skilled enough with electronics to make myself dangerous, so we'll see how this goes.I'm just starting down this road, so not much to say just yet. There's no trace, but I get a dot when pushing the beam find button.Looking at the 2213A Service Manual, a few of the items in the "Test Equipment Required" section I most definitely do not have access to:- Calibration Generator- Leveled Sine-Wave Generator- Time-Mark GeneratorAs I start to dig in, I imagine whatever I find will ultimately dictate how necessary these may be, but are there easy-button substitutes for any/all of them if I find I do need them?A quick visual inspection suggests a bundle of bad resistors on the main board around R256 - R271, and R888 - R891, both judging by darkened PCB material under these areas.R266 - 271 appear to tie the upper and lower CRT vertical deflection plates together, and all appear to be 150Ω from the schematic.R256 and 257 appear to be 649Ω and are each on the base for Q256 and Q257 respectively.R888 - R891 are all in series off the collector for Q885, and are all 510k.Having near zero electronics repair experience, would a wise first step be to order up replacements for each of these, swap them out, and see if that's it? Are there other things I should look for in unison with these before ordering parts up? If I do order replacements, how do I determine viable modern replacement parts?I've found a couple of threads discussing replacing the electrolytic caps in these scopes; is it worth tackling that while I have it opened up?Thanks!

author: bdunham7
author_rank: Super Contributor
timestamp: March 14, 2025, 02:31:02 am
content: You shouldn't start by replacing parts, especially not parts that are in no way related to your issue. The PCB turns dark (especially the light green versions) because the resistors produce heat during normal operation. The only resistors on your list that have a known history of failing are the R888-R891 focus ladder resistors and if you replace them preemptively use this part:https://www.mouser.com/ProductDetail/Vishay-BC-Components/HVR3700005103FR500?qs=sGAEpiMZZMtlubZbdhIBILNXVGfLCPaRkeSxzmI6Kd8%3DHowever, if your dot is focused or focusable, then those resistors aren't bad either. Certainly you need to try measuring before replacing.What other tools do you have? Zero repair experience can be overcome but no basic tools makes it pretty difficult. A DMM or two and some sort of signal generator are a minimal point to start from. I'd recommend doing as complete a troubleshooting job as you can before you replace any parts, even if you intend to replace those parts later anyhow.

author: CuriousRambler
author_rank: Newbie
timestamp: March 14, 2025, 03:07:24 am
content: Glad I asked! Thanks for your reply.I have all of what *I* would consider "the basics," including a good DMM. Aside from the items I listed, I have everything listed in the service manual except another oscilloscope, my DMM won't handle 2000VDC, and I might be missing one or two of the listed BNC adapters. If a second DMM will help, I can get my hands on one easily enough. The only signal generator I currently have is a cheap Chinesium PWM generator I bought to try to fix a dead truck odometer, a project I've yet to get to. When you say 'some sort of signal generator,' are you saying just to hook to an input to test for a signal on the screen, or something more precise? I've got 3.5mm TRS breakout adapters, easy enough to play a test tone from a phone to have *a* sine wave, but it obviously wouldn't be good for anything very demanding.I have a decent amount of random electronics fabrication experience with through hole, SMD and random scratch-built sensors under a microscope. Lots of larger scale integrated systems stuff, but my board-level troubleshooting experience with stuff "inside the case" is limited to things much more basic than this.I honestly don't know if I actually played with the focus adjust at all. I was able to move the dot around, and the intensity seems to work fine, but I can't say whether I played with focus. I'll slip the case back on and test that tomorrow. I'm planning to spend a bit more time with the service manual over the next week and start actually following test procedures that are laid out, I just figured if a quick visual revealed a smoking hole through the board, it might be an easy start

author: bdunham7
author_rank: Super Contributor
timestamp: March 14, 2025, 03:30:09 am
content: A good DDS/AWG signal generator can replace all of the stuff you listed as not available. However, just for going from dead to not dead, anything will do, even one of those $10 kits. Your phone will work for now.https://www.ebay.com/itm/285739001901Leave the PSU cage on and avoid the HV section on the underside of the board for now. If you have a glowing dot your HV section is likely at least alive.Troubleshooting no trace starts with XY mode and nothing connected to the inputs. Select XY and then see if you can move the dot onto the screen with the position knobs.

author: CuriousRambler
author_rank: Newbie
timestamp: March 14, 2025, 01:29:33 pm
content: Played around a bit more with the triggering, and I'm able to get two ~150ms alternating traces while holding the beam find. Both are adjustable up/down, left/right, focus, and intensity. I'm heading into a busy weekend leading up to a week out of town, so I likely won't get much more hands on time for about a week. Time I plan to spend familiarizing myself with the service manual.Edit: I didn't catch your XY mode comment, I'll try that out asap.XY mode just produces a fixed dot on the screen. I am able to move, focus, and adjust intensity, but nothing is traced out for any combination of settings I tried.