Sunday, September 1, 2013

Fixing TEK 465 Oscilloscopes



I'm having TeKnical difficulties.  My beloved Tek 465 'scope quit on me.  I'd been running it continuously for a day or so, watching the output on my BITX VFO.  Then, suddenly, it blew the 1.5 amp fuse.  I replaced the  fuse, but afterwards the trace was gone and the "Low Line" light was acting weird -- on when it should have been off, then flickering.   I consulted with Alan Wolke.  He happened to be out at TEX HQ in Beaverton, Ore.  He provided some good suggestions, but before I had a chance to try them, the trace came back.  I attributed this good luck to the Radio Gods being pleased with Alan's presence in Beaverton... but my reprieve was short-lived.  Trace went out again today. 

I found this video of the legendary Jim Williams (RIP) fixing a Tek 465.  (Check out Jim's junk box!)
I'll start by checking the Tantalums.  I may get lucky. 

If anyone has any other suggestions, send them this way.  The Tek scope may be old, but it is a COMPLICATED piece of gear... 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
at

4 comments:

  1. UnknownSeptember 1, 2013 at 3:50 PM

    First want to say I enjoy reading your book and blogs, they inspired me to build my own QRP equipment. I am am interested in hearing what turns out to be the problem with your scope, I have a Tek 545B that is been giving me some problems, trace disappears after being on an hour or so.

    ReplyDelete
  2. Chris M6CRDSeptember 1, 2013 at 6:08 PM

    Best advice I can offer:
    1) Close visual inspection starting with the PSU section.
    2) Start tapping around with a plastic/wood rod with the scope powered up and watch the screen. This can sometimes narrow it down.
    3) Freeze spray (or canned air turned upside-down). Rapid cooling spots on the PCB while powered can reveal components failing at (or above) ambient temperature. Very useful method, and saves time.
    Good luck Bill, I'm confident you'll have it's heart beating again.

    ReplyDelete
  3. AnonymousSeptember 3, 2013 at 2:35 PM

    Your best friends are in the Yahoo! Group: http://groups.yahoo.com/neo/groups/TekScopes/info
    Mention your problem there and meet the real wizards of CRT scopes!

    And download this file: http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf

    73 de Robert PA7RG

    ReplyDelete
  4. AnonymousSeptember 3, 2013 at 2:40 PM

    OK, you have already found the Yahoo Group!

    Good luck fixing your Tek 465!

    Robert PA7RG

    ReplyDelete