Tektronix 465B repair

[Cubdriver]

This one?

http://bunkerofdoom.com/tubes/crt/crt_p ... search.pdf

-Pat

[tautech]

How the fuck do I attach a 200kb pdf ?

Zip it and attach the zip file.

Thanks, done.
Okay, anything not an image file, zip.

[tautech]

This one?

http://bunkerofdoom.com/tubes/crt/crt_p ... search.pdf

-Pat

Yep, same and attached as a zip file couple of posts back.

[AVGresponding]

I found a possible parts donor machine for you Chris:

https://www.ebay.co.uk/itm/285495004714

[mansaxel]

Everybody needs a 485 for its 50ohm input. Helps if the user can do mental arithmetic, rather than relying on cursor readout

I happen to prefer my 2465CTS with 50Ω input and cursors with readouts, including a frequency counter... But, the 485, being the last of the fully discrete scopes, is something. Not likely to turn up on this side of the pond, not for sensible money at least.

This thread makes me think again about daring to fix my 5440, whose horizontal plugin has a faulty custom IC I have the replacement, though.

The 5440 is not a spectacular scope in terms of bandwidth or so, but the display is large and on my specimen, very sharp and clear. Probably the optimum LF scope in my arsenal (Fluke 123, Teks 465B, 2465CTS, and a dead TDS520 choc-a-bloc with leaky SMT electrolytes) once I get it to work. There's a headless curve tracer on the local auction site, which would work wonders with an X/Y displaying scope of that screen quality. Now, I don't remember if the plugins I've got do X/Y, but regardless. The 5440 is gorgeous, display-wise.

[tggzzz]

Everybody needs a 485 for its 50ohm input. Helps if the user can do mental arithmetic, rather than relying on cursor readout

I happen to prefer my 2465CTS with 50Ω input and cursors with readouts, including a frequency counter...

I think you'll find it is 50ohm//20pF => the usual crap VSWR. That can matter with a Z0 probe or anything else with a 50ohm cable.

But, "stamp out adjectives and use numbers" https://www.eevblog.com/forum/beginners ... msg4969791 shows 485 vs 2465.

But, the 485, being the last of the fully discrete scopes, is something. Not likely to turn up on this side of the pond, not for sensible money at least.

This thread makes me think again about daring to fix my 5440, whose horizontal plugin has a faulty custom IC I have the replacement, though.

The 485 I sold had an integrated circuit which was internally faulty. I repaired it, but the rise time increased from 1ns to 1.25ns.

485.gif

One of the resistors was open circuit, so I added an SMD resistor across some nearby convenient terminals.