Jeff, I found this invaluable in sorting out the sweep logic for the 465 I'm working on: https://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf The sweep flow diagrams later in the book ar

Looks like I found the problem! I'll have to add Q1038 and Q1098 to my horizontal amp simulation. Clearly both of these transistors need to be in place and working for the correct DC level on Q1224bas

Yeah, I didn't get into Q1218. It did have me running in circles a bit too because of its -8v at the collector. I did a couple of things: removing it and trying running the scope without it. No effect

Is there a resource for the sockets that are soldered into the PCB boards in scopes with plug-in transistors, ICs, diodes, etc.? Dave

Or Amazon Prime! LOL. I guess I have a bias against Amazon for such things. Kind of like Radio Shack. But why? I guess as long as I shop carefully and understand I might not be getting the best qualit

I have removed Q1226/Q1236 PNPs with no effect. They are not part of the problem. This is also part of why I built the LTspice simulation - to get insight into the current switching going on. I've als

David, In my limited experience, I have seen this behavior before, but it's always been due to probe issues. Usually with a long ground lead. Readjusting the probe and ground for better connections at

Getting right to it: Wes' friend agreed to ship the scope out to me. I've got it and another 465 belly up on my bench at the moment. There are a couple/few issues: the sweep logic chip U870 is being f

Is it appropriate, viable, and reasonable to use a 240v -> 120v converter to provide "proper" 120v grounded line source to Stephen's 4xx oscilloscopes/equipment? It seems that perhaps it is the nature

Yep, just found the horizontal amp you sent. Too perfect. This is exactly what I was working toward: I have the 465 Wes Bolin was working on for his friend in the garage. I'm going to try my hand at r

Ozan, Ah, you're who sent the LTSpice reference. Yeah, thanks so much. It's simplistic, but does everything it needs to do. I can live with rotate-mirror-rotate vs. vertical-flip. BFD. I love simple.

There are many facets to this experience for me: One is that I want this info in the groups messages in the hope that it might help others in the future. So pardon if this is rudimentary for the more

LTSpice schematics: https://groups.io/g/TekScopes/files/465_Probe_Indicator_Select.asc https://groups.io/g/TekScopes/files/465_Probe_Indicator_Select_Modified.asc Dave

Sorry Dave. The link was to the thumbnail. The full picture can be expanded by finding it in the thread: https://www.eevblog.com/forum/repair/tektronix-465/msg697587/#msg697587 Not so much theatrics a

Here's a hint: https://www.eevblog.com/forum/index.php?action=dlattach;topic=45906.0;attach=157509;image What's wrong with this picture? Dave

Hi All, Been working on replacing 465 Volts/Div range bulbs with LEDs. Has anyone here actually done this before? I've tried searching here and EEVBlog forum, but I've either gotten too many results o

Jeff, What you're describing doesn't sound terribly sacrilegious. I'm sure we've all seen far worse. I like your take that a glue repair lends itself to a deeper repair later. I presume you personally

Don't forget the development time, and R&D experience. Marketing drives product development, and is a best guess at the time of project kick-off. Markets shift (and boy didn't they in the 80s!) and so

I'm using the PDFs from the Tek Wiki for now. Prefer hard copy. I went though all of the PDFs for the 2236 on Tek Wiki yesterday to find the right one to recommend to the eBay seller for printing. He

That's quite a leap from the 2235 to the 2236. Yeah, I think it'd be a fair guess as to why the 2235 is literally available by the pallet on eBay today, and the 2236 not so much. Any chance of taking