Tektronix 2232 repair advice. - Page 1
Forum section: electronics / repair

author: jmczaja
author_rank: Newbie
timestamp: March 20, 2025, 05:12:02 pm
content: Hi folks. I have a Tek 2232 in good working condition with the exception that the A Trigger level potentiometer's shaft seems to have broken off from the pot itself. The knob itself is wobbly and the shaft is obviously broken. That said, it still works if you push and turn it at the same time. It's been like this since I bought it. I purchased a replacement pot years ago but have been putting off the repair since everything still works and it seems like quite the task to remove the front panel PCB after reading the service manual. Part of me says leave it be, it works but the other part of me wants it fixed!My hesitation is not disassembling and replacing the pot but rather recalibration if needed. What are the chances of needing a recalibration after disassembly/reassembly? I would think everything should be fine if careful but wanted some reassurance. I don't have the equipment needed to properly calibrate if needed.I'm a hobbiest who works on audio projects (amplifiers, synthesizers, etc) and this particular scope suits my needs.Thanks in advance!

author: wn1fju
author_rank: Frequent Contributor
timestamp: March 20, 2025, 10:16:58 pm
content: My guess is that things will be very close to what you started with after replacing the trigA pot. Whether it will be perfect, like will the trigger readout be perfectly accurate, might be questionable.However, to be sure, the trigger adjustments in the 2232's service manual are fairly easy. You really only need a function generator at a low frequency like 50 kHz in order to get something on the screen that will enable the trigger adjustments to be made. Don't be afraid to do it.Any chance you could put a dab of super-glue on the broken shaft and fix it?

author: jmczaja
author_rank: Newbie
timestamp: March 20, 2025, 10:55:14 pm
content: Quote from: wn1fju on March 20, 2025, 10:16:58 pmThe only way to get at the pot is to remove the front panel PCB which basically requires disassembling the entire scope. I haven't disassembled the scope yet so I can't say exactly how it's broken but the knob rotates freely unless pushed so I can only assume the shaft was stressed in some way and snapped.The replacement part has a metal shaft. Super-glue won't help me here I'm afraid.If I have time I'll get it disassembled over the weekend and see what's what. I already did a partial disassembly and put it back together to see what I'm up against and it wasn't so bad. I was bit nervous about removing the CRT but it was fairly uneventful.

author: bdunham7
author_rank: Super Contributor
timestamp: March 20, 2025, 11:21:51 pm
content: Quote from: jmczaja on March 20, 2025, 05:12:02 pmYes, that's a pain to take apart. Replacing the pot won't change anything with the trigger or readout, but if you do find the readout to be off it is easily adjustable without any fancy equipment. However, I had one like that once where the trigger readout was way off but the trigger worked normally. It was a bad jellybean transistor deep in the front PCB and that was very difficult to diagnose and replace. The whole job is time consuming but doable if you are careful and methodical. Where I run into trouble is doing it the second or third time when I'm feeling confident then I make a mistake. Always be very careful during CRT removal and replacement, it's easy to forget something or get those little side pins caught on something.

author: David Hess
author_rank: Super Contributor
timestamp: March 21, 2025, 01:06:39 am
content: Quote from: jmczaja on March 20, 2025, 05:12:02 pmBasically no chance of requiring recalibration unless you fiddle with something that you should not.QuoteIt only takes very basic equipment to check calibration, like a function generator and multimeter.

author: jmczaja
author_rank: Newbie
timestamp: March 21, 2025, 01:40:45 am
content: Quote from: David Hess on March 21, 2025, 01:06:39 amMy plan is to be in and out, no fiddling around.Quote from: David Hess on March 21, 2025, 01:06:39 amPerfect! I have that covered. Thank you!

author: beenai2018
author_rank: Contributor
timestamp: March 27, 2025, 07:29:19 am
content: I had to get into a tek 2236 and one thing that helped me was to label and tag the connectors. Also most of 2236 connections were not keyed so a matching mark is most useful.

author: jmczaja
author_rank: Newbie
timestamp: April 08, 2025, 11:12:04 pm
content: Finally got around to replacing to pot today.. What a pain in the neck it was to disassemble and reassemble. It took me about 6 or 7 hours total to install the new pot.No leftover screws and it still works! hahaThanks for the advice!

author: marcumr
author_rank: Contributor
timestamp: April 09, 2025, 06:24:46 am
content: HELLOThe second time it will take you 3 hours, the third time 1 hour works like this