No sweep at all, Tek type 321 A

Update after 2 weeks, I now have a dot that appears at every division! The sweep isnt working though.

Hello Carden. I have worked on a few ‘scopes over the years mostly Tek but the specialized Waveform & Vectorscopes for composite video (from back when that was a thing)! That said i recently had a  two channel Philips Storage scope that had lost its Timebase completely upon all selections of the TB rotary switch. It produced a single dot on the very special CRT that did the actual storage function. That trouble was traced to an open circuit sort of MOV (Metal Oxide Varistor) both channels. Philips used a very weird design to couple the sawtooth signal for Timebase sweep into the final drive transistors via these specific in-house MOVs which are now utter ‘un-obtainium’ now as a spare part. Safe to say i ended up using a reverse biased vintage IR diode of all things & the circuit worked again! 

I doubt you will need to do anything this crazy on your Tek though! What enabled that full repair in each case was having the full Service manual meaning lots of detailed info & a second reasonable spec operational oscilloscope to hand so as to view just what isn’t happening in the Timebase circuit. (The service manual schematic usually provides small diagrams of what signal should be present at each node along the circuit).

Without these things it’s going to be a bit of a slog to define where the fault lies TBH. There are also loads of other snippets of info upon how folks have restored their 321A ‘scope which you may have already found, in many other Forums. 

Feel free to let us know how far along you are on this project & if you have a the Service manual plus access to another operational oscilloscope. The manual is here FWIW: https://archive.org/details/tektronix_321a_scope

@carden-stephenson Which cap did you replace and with what kind? Time base circuits obviously have many critical components to ensure proper operation. Get into the manual and read about how it works and that all controls are properly set. From there you can follow through troubleshooting and trace out the issue.

@peteb2 Sorry I’ve been a bit busy at work,  my tubes look fine. I have a working Leader 8020, that I have been using on this project. From what I can tell the problem lies in some bad transitor replacment attempts. I now can get the trigger signal to go to C151, but at the “output” of the cap the signal is dead. I have replaced the cap which helped a bit, but something else is killing/loading the signal. The only thing i now is its not q135 or q145 thats killing the signal.

Also ive seen a bit of info on other sites let tek wiki and  https://groups.io/g/TekScopes/topic/321a_2n2207_transistor/7640286.
I do have a physical version of the manual.

Thanks, Carden.

@radtekman I replaced most caps that are actually connected to the switch, so the c180’s and c160’s, I replaced them with mostly ceramic but, i did replace the mica cap(0.00033 uf) with a mica and most of the electrolytic caps with axial electrolytic caps.
Ive gone through the manual multiple times during this project, but, throughout today I’ll got through it again and see what ive missed.

Thanks, Carden.

Update.
The “dot” that appears is still not becoming 2 dots during calibration, but if I use my Leaders calibration out(1v pk-pk) I can see the waveform appear but not sweep. Also the transitors seem to be getting the right wave forms at the right voltages but the Volt Division is messed up, to see a 1v Square wave, I need to be at .01 V div.

@carden-stephenson The caps on the switch are critical for accuracy as they are 1 percent caps that would not cause a time base to stop. Micas are generally going to be fine as well. I would be checking transistors and verify placement to start. Set the scope up as directed in the schematics and start comparing waveforms. Once you find an issue check components in that area. Also check what kind of probe you are using to trace, a x10 probe would correlate to readings on 0.1 volt for a 1 volt signal. It would also help prevent loading the circuit as much.