| Products > Test Equipment |
| Tektronix 2235 repair thread |
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| ahmedseecs:
Hi, I have recently acquired a Tektronix 2235A that works fine for couple of minutes but as soon as the oscilloscope warms up the display get defocused. Can you please suggest the possible cause for it.I am quite new it I did try going through the service manual but was unable to understand the cause . Thanks for your help in advance. |
| bd139:
Possibly focus pot failing or the divider resistors. See further up this thread for 510k resistors. Very common problem. Replacement pot is fairly unobtainable. I managed to salvage a pot out of another failed scope (different brand) that worked. Try replacing the resistors first though. Think it’s 4x 510k ones. You need Vishay VR series which are properly voltage rated as there are quite a few bolts across them! |
| TERRA Operative:
I managed to find a new and unused pot on ebay a while back, so you might get lucky if you keep an eye out. Here's the resistors (in blue) I replaced in my 2235, I would replace all 6 if they are present in your unit, just to be safe (resistor are cheap anyway, and it means you don't have to open the scope up for this resistor issue again. :) ) |
| Ze Pink Panther:
Good evening everyone, I hope this thread is not completely dead. My problem concerns the Tektronix 2235 Service Manual. It is (now) widely available on the net (even fron the Tek web site), but all the versions and copies I've seen have all the same problem: all the folded pages (containing mostly schematics, which makes them even more important and critical) have a scan gap in the middle, which results in column H of the schematics having almost half of it missing. Can you point me to a source where the SM is _fully_ scanned? Thanks in advance and regards, ZPP |
| TERRA Operative:
I have a copy of all the 2235 foldouts, available here, along with a bunch of other stuff including high quality scans of the manuals: https://drive.google.com/drive/folders/1L2ptk_0OeEywzHXIV2jmTQYrtf5IzgIH?usp=sharing It's the 'Tek 2235 Foldouts large.pdf' file |
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