Tek 547 or Space Heater Saves the Day

Discussion in 'General Electronics Chat' started by tindel, May 2, 2016.

  1. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    It has been cold in Denver this weekend... snowing off and on - and thanks to @Lestraveled I stumbled upon this gem on Friday night - just as the storm was rolling in.
    Craigslist.png

    So Saturday morning I put my daughter in the Jeep and drove an hour - through snow and sleet - to get to Ft. Collins to get the thing. Google has the opening time of the thrift store at 9am. Turns out the place really opened at 10am. So I impatiently waited. Finally 10am got there and me and my girl ran inside casually looked around a bit and then I saw it... and new I had to have it. I have been looking for a 547 for quite some time. I didn't want to pay too much, but I also wanted to have a bit of a project. I bought it. I didn't open it or look at it much - I knew I had to have it. The price was right and it's arguably the most sought after scope that Tek has ever produced... I just rolled it out to the front of the place and paid the 90 something bucks after tax to roll it out of the building.

    When I got it home I was a bit shocked at the size of this thing. Worried a bit what the wife would do when she too saw the size. It was filthy. 50 years of filth. So I started cleaning.
    20160501_185934.jpg

    And cleaning....
    20160501_193542.jpg

    And cleaning...
    20160501_201018.jpg

    Finally she emerged. Beautiful. I've owned a couple of scopes from this era... I still can't believe how magnificent they are - this one in particular. The more I cleaned the more I realized... there wasn't a single tube or transistor missing, and that it had been stored for the last 50 years in a controlled environment (extremely important due some high voltage problems that 547's are known for). The fan and filter were barely dirty. It started occurring to me that this thing looks like it has barely been used. It's a showroom piece. It just needed some sprucing up. Some of the areas in the scope were spotless and I did NOTHING to them... the high voltage and power supply area were particularly clean. The only place with dust were places with a bit of a gravity assist. Really, the only thing I've found wrong so far are a few resistors showing their age that I will probably replace, missing the polorized lens for the crt, and the knobs and red on the front of the machine are faded quite a bit.
    20160501_202317.jpg

    I have yet to power it on. I'm also working on getting my variac up to snuff and researching how to bring back electrolytic caps from a 30 year hiatus (the last cal sticker on it was 1983). I'm open to input. I did find that a dry rag and a magic eraser seem to be a good combination for cleaning nearly the entire device. I'm not crazy about the C plug-in that it came with - so I haven't cleaned it - in favor of looking for a good 1A4 plugin to support 50MHz bandwidth instead.

    I am really hoping the HV transformer isn't shot - I'm keeping my fingers crossed.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,364
    Congrats on your latest find.
    Did you find a small spool of silver solder on the back?
    The ceramic solder tag strips are soldered with silver solder.
     
  3. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    No silver solder in this one
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,035
    3,242
    Those are good space heaters (or boat anchors).
    I remember at work we would have to be careful that not more than one was plugged into any single bench circuit or it would blow the breaker.
     
  5. RichardO

    Well-Known Member

    May 4, 2013
    1,238
    384
    Let me be more direct. You WILL destroy the ceramic terminal strips if you do not use silver bearing solder!
     
  6. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    Thanks RichO... I'm aware of that - and I do have some of the correct solder in my 564. I think the HV transformer is out on the 564 though - the horizontal sweep gets longer and I have a difficult time focusing the beam which is the primary failure mode. At least I have a scope to get some parts out of (tunnel diode's and rare tubes, mostly).
     
  7. RichardO

    Well-Known Member

    May 4, 2013
    1,238
    384
    Great buy! I have seen the cart alone cost that much.
    I notice that it has a handle (2 actually) on it. That means that it is a portable scope. :D

    Looking forward to your reports on getting it going...
     
  8. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    1,190
    156
    If you need some silver bearing solder just let me know ..
     
  9. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,364
    I'm surprised there is no solder in the 547.
    Here is the solder in a 503.

    Tektronix 503 Silver Bearing Solder.jpg
     
  10. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    Yes, I am familiar with the spools of solder in the old scopes... I even have some in a 564... this one just doesn't have any. I'm guessing that someone just took it out of there at some point.

    @Dr.killjoy - thanks for the offer - I might take you up on it at some point if I run out of the spool I have.
     
  11. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    1,190
    156
    I know I have a roll of some Benzomatic silver bearing solder laying that never gets used..
     
  12. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    So I'll throw this out there... how would you go about turning this thing on? I've read a lot of extremes everything from just power it on and see if it works (bad idea I think) to replace all the caps before turning it on (also a bad, I think, at least until I see the HV transformer working reliably).

    These are my options, as I see it:
    • Just power it on - this is something that I believe the thrift store did when they brought the unit into their store... I'm not crazy about that though. I can probably check for shorted caps prior to turning on so that would hopefully at least keep me from damaging my caps, fuse, or most importantly - the input transformer.
    • Just power it on with a couple lights in parallel and in series with the line so if there is a short on the scope, the bulbs turn on. This doesn't reform the caps though.
    • Remove all of the input capacitors and reform them with a variac and test them all individually. This way I can replace ones that truly need replacement and can continue to reuse ones that are still working (if any).
    • My personall favorite - I've been thinking about removing all of the power from the circuitry and putting dummy loads on all of the voltage regulators and bringing up the voltage slowly with a variac to at least reform the input capacitors and check for proper regulation before applying the output of the voltages to the rest of the scope.
    • Powering on the entire thing with a variac - maybe starting at 50%
    • Replace all of the caps then turn it on... This isn't a bad option... just time consuming and expensive. Replacing all of the caps is something I might consider after seeing the unit work.
    I'm open to suggestions.... Remember though - as far as I can tell this scope has very few hours in it's lifetime. It is nearly in mint condition - and I am slow to make decisions on what to do with it.
     
    Last edited: May 4, 2016
  13. Picbuster

    Member

    Dec 2, 2013
    376
    50
    It was the best scope in that time indestructible with a lifetime warranty on the transformers. Those pictures send me back to the university time.
    It came with full manual and description of all circuits plus b.o.m.
    One small negative point those scopes need a lorry to move them from one place to the other.
    But unbelievable stable.
    Keep and cuddle it's superb quality.
     
  14. crutschow

    Expert

    Mar 14, 2008
    13,035
    3,242
    I would just slowly power the entire thing up with a Variac to give the electrolytics time to reform.
    If you could monitor the current at the same time with a multimeter or a Kill-A-Watt meter that would be a plus, since it would indicate if anything appears to be drawing too much current.
     
  15. recklessrog

    Member

    May 23, 2013
    338
    102
    Wow! better check the Flux capacitor too in that time machine ha ha. Seriously though, they were superb in their day and kept us nice and warm in the winter time. Good luck firing it up :)
     
  16. crutschow

    Expert

    Mar 14, 2008
    13,035
    3,242
    Those Tek tube scopes were likely the epitome of quality in point-to-point wiring of a circuit (and there original cost reflected it, about as much as a new Chevy at the time).
    Those neat ceramic terminals were probably used on few other devices but they had lower losses than the more common phenolic insulated terminals.
     
  17. ifixit

    Distinguished Member

    Nov 20, 2008
    639
    108
    I had one of those and it worked well. Sometimes i would turn it on just for the warmth.

    When it is switched on only the filament power comes on at first for 10 seconds or so, then a relay clicks and the rest of the voltages are applied. If you bring it up with a variac you may upset this sequencing. I would just turn it on, but ensure that the fuse is correct in it, or even replace temporarily with a slightly lower value. Also, set the intensity to minimum. You could also monitor the AC line current, it should be no more than 4 Amps or so after the power on sequence is complete.

    Good luck,
    Ifixit
     
  18. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,364
    @ifixit has a point there. I have greater than 50-year old equipment still running strong with no parts replaced.
    The Tek TYPE 503 still works fine.
     
  19. tindel

    Thread Starter Active Member

    Sep 16, 2012
    568
    193
    I finally got the nerve to power this thing on. I fired it up and and it came up very nicely. The fan came up slowly - but eventually got up to speed. Then about a minute after turning it on I hear the relay click and the rest of the scope continues to come up. I increased the intensity adjusted the focus and astignatism and put it on a auto trigger and got a trace!

    The pots need some more cleaning. There was lots of noise on the trace particulary with the vernier adjustment on the vertical amplifier. A minor calibration probably needs done. The calibrator is working - although at about 1.25kHz insead of 1kHz. Although it could be 1kHz and the time-base could be off a bit. The most important thing though is that I ran it for an hour or two and the HV transformer seems to be working perfectly! This model does have a problem with the HV transformer.

    Attached are some photos of the calibrator. Note that the signal is only going into one input... I'm using the AB ALT function to trigger on dual time bases! It's pretty cool that an analog scope could do this 60 years ago. There are a few more things I need to test, but most everything is working properly

    20160525_211554.jpg 20160525_211604.jpg
     
    RichardO, ifixit and Lestraveled like this.
  20. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Those pictures warm my heart.
     
    RichardO and tindel like this.
Loading...