Author Topic: Restoration / Repair of Tektronix 545 - Finished.  (Read 15930 times)

0 Members and 1 Guest are viewing this topic.

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #50 on: September 26, 2016, 08:36:54 am »
Interesting history re this and other 500 series beasties, mine has what i think may be called "stick rectifier" diodes in the HV supply, these are definitely clip in. They appear to replace the tube type HV diodes.
Below is a photo of my 'low voltage' rectifier diodes i.e. 100 tp 500v supplies and the associated dropper resistors, it is looking in from the RHS of the unit , with the front to the left in the photo, top of the photo is up on the scope. These diodes are definitely soldered in but all are working.
Below that is a Rob CAD layout of the diodes and dropping resistors (shown as a circle with a cross) on all but the 350V supply. The outermost of the dropper resistors is connected to the diodes and the innermost of the dropper resistors is connected to the series current limiter resistors usually 10ohm (on the very bottom of the unit). The diodes are in blocks of 4, and I have drawn this as a square and the positive rail is marked with a + sign on my "CAD" drawing.
Had to do some other jobs around the home to keep Mrs VK5RC happy today so didn't get much time on the old girl today.
Whoah! Watch where that landed we might need it later.
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #51 on: September 29, 2016, 07:39:07 am »
Looking more carefully at the 225v regulation circuit, I couldn't find any badly out of value components.
Testing the circuit it did appear to try to compensate for the drop in voltage but the gain was not enough to fully compensate, on start up 215v sagging to 190v when hot.
Replacing the 2 amplifying tubes in the feedback part of the 225 regulatory circuit appears to have mostly stabilised the voltage, so it goes from 215 on start up to about 209 when hot. This sag does not appear to be enough to 'upset' the multivibrator circuit in the main trigger circuit.

It triggers properly on first start up and for 20 mins of running - I am happy with that.  :-+

Back to a bit more of the body work!
Whoah! Watch where that landed we might need it later.
 

Offline silverlego3

  • Contributor
  • Posts: 13
  • Country: us
Re: Restoration / Repair of Tektronix 545
« Reply #52 on: September 29, 2016, 04:54:53 pm »
Here is a Tektronix 555!!
"Work Smarter, not harder"

"Its hard to soar like a eagle when your flying with turkeys"
 

Offline Martin.M

  • Frequent Contributor
  • **
  • Posts: 518
  • Country: de
  • in Tek we trust
    • vintage Tek collection
Re: Restoration / Repair of Tektronix 545
« Reply #53 on: September 29, 2016, 05:25:23 pm »
Triple Nickel, 555

it`s better to own two of them, so the one will help the other if there is a problem  :)

greetings
Martin
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #54 on: September 30, 2016, 06:48:02 am »
If you have too many 555s,  I would always be happy to look after one for you! HiHi.
Whoah! Watch where that landed we might need it later.
 

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545
« Reply #55 on: September 30, 2016, 07:27:36 am »
Yeah, right?  A triple nickel is on my wish list too - winter's coming!

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #56 on: September 30, 2016, 07:49:10 am »
It is interesting that my 545 has stopped smelling of burnt dust after about 15 or so 10 to 15minute runs,  there is something rattling/buzzing  next to the fan,  makes a racket,  not that keen on poking around when switched on!
Whoah! Watch where that landed we might need it later.
 

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545
« Reply #57 on: September 30, 2016, 08:10:53 am »
Does it seem to be a mechanical vibration caused by the spinning fan, or something like a lamination buzz that's at line frequency?  Do you have a chopstick, or wooden dowel,or the like?  That could be something to poke around with to try to determine what's making the noise.  (I wouldn't suggest a pencil, since it has that built in resistor in the middle...)

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #58 on: September 30, 2016, 08:19:30 am »
While avoiding the issue, (allowing me time to think about it - reminds me of the great quote "Sometimes I sits and thinks and other times I just sits" ; Chic Sale "The Specialist")
I was thinking along similar lines, a bit of DRY wooden dowel with a rubber tip or fine PVC pipe (after a megger test for good measure)!
Whoah! Watch where that landed we might need it later.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 15712
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Restoration / Repair of Tektronix 545
« Reply #59 on: September 30, 2016, 08:48:54 am »
You're being unnecessarily cautious Rob, where's your sense of adventure?  :o  :-DD

Do these old girls have a PDA supply, if not the only few hundred volts for most of the scope is not too dangerous if you are careful. Same old story, while poking around be sure to have the other hand in your pocket.  ;)

As others have said, chopstick, wooden skewer, pencil (blunt end) or even a hot melt glue gun stick can suffice.
If I was worried about shorting something and only had screwdrivers I'd be grabbing an electricians style one, one with insulation along most of it's shank.
Avid Rabid Hobbyist
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #60 on: September 30, 2016, 09:15:37 am »
You betcha I am cautious! (makes chicken noises!!)

The 10kV supply, while measuring the voltage with my homemade/kit 20kV voltage divider,  gave lovely little corona type sparks off when measuring at the middle voltage doubler diodes - I suspect due to capacitance of the probe itself. At least the 10kV supply normally has a protective cover on, The other 100-500v are all over the place and there are no covers on this puppy at present. These "Low Voltage" (the Tek term for the 100-500v supplies - it does stretch the definition in my mind) can supply several hundred milliamps and on the chassis is a warning that they can be more dangerous than the HV supply. (more chicken noises)

I am not sure what PDA stands for, I couldn't find anything on a quick Google. The low voltage supplies are pure conventional linear regulated supplies, each one has its own transformer secondary, diodes, regulating circuit and filter cap. The only slightly tricky bit is the -150v supply is used as the voltage reference for all the others .
I will try to sort out the noise cause it is pretty irritating at present.
Whoah! Watch where that landed we might need it later.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 15712
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Restoration / Repair of Tektronix 545
« Reply #61 on: September 30, 2016, 09:21:30 am »
20kV  :scared: yep that's the PDA (Post Deflection Acceleration) supply.
Chook, chook, chook....I'm out of there too.  :phew:
Avid Rabid Hobbyist
 

Offline jh15

  • Frequent Contributor
  • **
  • Posts: 452
  • Country: us
Re: Restoration / Repair of Tektronix 545
« Reply #62 on: October 01, 2016, 06:39:20 am »
Rubber fan moubts hardened? I think I used hardware store gtommets on my Tek curve tracer.

Oh, my favorite tapping tool: chopstick.
tek 575 curve tracer top shape, 535 top shape, 465. 545 hickok clone, Telsa Model S,  Ohio Scientific c24P single board computer, many c-64 from my club days, Giant electric bicycle, Rigol stuff, Heathkit AR-15 receivers 2, Heathkit et 3400a trainer and interface,
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #63 on: October 01, 2016, 10:00:12 am »
Thanks guys, I am still alive. Took some brave pills, tested (merger) then used a BBQ kebab type wooden stick. As surmised it is the fan, but it is the aluminium mounting that holds the fan motor. I have already replaced the  rubber mounts, RS Components stock them, they are quite soft, they deform about 1mm (of 10mm) just with the weight of the fan so seem about righting my thinking. I think I might try and make a little absorbing panel from some car sound deadening adhesive sheet. I also have some thin 2mm from rubber sheet I might try first.

Today was a panel day.
The side panels were in pretty bad nick, a few weeks ago I took the bottom panel (Minimal fading) to a special paint warehouse and for about $90 AUD they mixed up 2 spray cans of paint to match TEK blue. It isn't textured like the original but it is matt and is a very good colour match.
Today I sandblasted the panels, primed them, then top coated, I am pretty happy with the results. Photos before then sandblasted;     primed and after (in next post)
Whoah! Watch where that landed we might need it later.
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #64 on: October 01, 2016, 10:01:28 am »
Primed covers then top coat
Whoah! Watch where that landed we might need it later.
 

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545
« Reply #65 on: October 01, 2016, 06:16:24 pm »
That looks fantastic!  Nicely done!   :-+

It appears that they did an excellent job on the color matching.

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 
The following users thanked this post: VK5RC

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #66 on: October 08, 2016, 03:09:13 am »
A bit of a problem, the top support bar, to which the handles attach and the side frames interlock, on the original were a chrome plating to an aluminium alloy extrusion. This had peeled quite badly and bits (of conductive!) chroming flakes were found in the scope. Sandblasting removed it all.
A quick trip to my local "Plating" company confirmed that plating to alloys is not good. I note that on some later Tek models the top bar is painted the same colour as the sides - so that is what I decided to finish with.
I also got some acoustic padding from Jaycar (used for car door lining etc) and padded the fan frame, it dropped the noise quite a bit.
Results below.
Whoah! Watch where that landed we might need it later.
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545
« Reply #67 on: October 08, 2016, 03:27:21 am »
Attention to the front knobs etc took the form of Meguiars  PlastX applied with a cotton bud to get in the slots of the knobs and then a quick finish with Armourall which leaves a nice shiny finish.
The scope had a few final adjustments and below is shown displaying a 1MHz sine wave ( the 'limit' of the plug in).
And a final shot.
Rough costs AUD
Scope                           $80
Tubes x3 ~                   $50
Paint (spray)               $150
Fuse Holder                   $10
Caps  (Electro)               $15
fan Vibration Mounts x3 $15
Various; Cotton buds (about 500!) , IPA, window cleaner, brushes, distilled water,  rags, silver solder. car polish, silicon oil, L&P gun oil. simchrome

Thanks to EEV blogers including EEV Dave, Martin.M, robrenz, tautech, cubdriver, Sue just to name a few , by sharing your knowledge I have gained a lot of confidence and am thus able to tackle projects like this. I have learnt a lot. Thanks guys. If any questions re what I have done please ask, happy to share what I did.
« Last Edit: October 08, 2016, 03:32:25 am by VK5RC »
Whoah! Watch where that landed we might need it later.
 
The following users thanked this post: tautech

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545
« Reply #68 on: October 08, 2016, 03:29:44 am »
Beautifully done, Rob - it looks brand spankin' new!   :-+ :-+

(Makes me want to do the same to the 575 curve tracer I got last year...)

-Pat
« Last Edit: October 08, 2016, 03:31:17 am by Cubdriver »
If it jams, force it.  If it breaks, you needed a new one anyway...
 
The following users thanked this post: VK5RC

Online tautech

  • Super Contributor
  • ***
  • Posts: 15712
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Restoration / Repair of Tektronix 545
« Reply #69 on: October 08, 2016, 03:44:13 am »
Thanks to EEV blogers including EEV Dave, Martin.M, robrenz, tautech, cubdriver, Sue just to name a few , by sharing your knowledge I have gained a lot of confidence and am thus able to tackle projects like this. I have learnt a lot. Thanks guys. If any questions re what I have done please ask, happy to share what I did.
Kinda knew you'd come up trumps with this one Rob so I added it to this other thread (don't know who started it  ;) )
https://www.eevblog.com/forum/repair/vintageclassic-renovation-techniques/msg1036368/#msg1036368

Nice work, thanks for sharing.  :)
Avid Rabid Hobbyist
 
The following users thanked this post: VK5RC

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545 - Finished.
« Reply #70 on: October 08, 2016, 06:08:44 am »
Thanks guys, the problem when you get these beasties is you don't know what could be wrong and getting 'that' part may be impossible because it was the dodgy part and everyone else has ripped it out of any 'parts units'.
Now cubdriver a 575 is a really lovely device, definitely worth the effort.  :-+
While pulling it apart I found it at one stage the 545 belonged to an interstate University dept, I am going to send the completed photo and a quick description of the repair to the Department tech officer for a laugh - see if I get a response.
Whoah! Watch where that landed we might need it later.
 

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545 - Finished.
« Reply #71 on: October 08, 2016, 07:03:47 am »
The 575 will definitely need some serious scrubbing to pretty it up, but it is at least somewhat functional based on some quick testing I did on it last year.  I finally got back into the Electro Instruments DVM tonight and at least cut all the new isolation mounts to length.  I've been putting that one off for far too long.

And I have to say, I'm still amazed at how clean your scope came out.  If I can get the 575 looking half as good I'll be pleased.

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2223
  • Country: au
Re: Restoration / Repair of Tektronix 545 - Finished.
« Reply #72 on: October 08, 2016, 07:20:23 am »
I had quite a bit of luck but Tek made good panels with lettering 'in deep' and good knobs of a sturdy plastic. Good manuals and not weird components in that vintage.
Nothing like putting it up on EEVblog to make you push it along!
I am still so envious of what you guys can get in the USA, so many sellers won't post outside the USA, but it might save me quite a bit of cash and space! HiHi
Whoah! Watch where that landed we might need it later.
 

Online TheSteve

  • Supporter
  • ****
  • Posts: 2962
  • Country: ca
  • GHz
Re: Restoration / Repair of Tektronix 545 - Finished.
« Reply #73 on: October 08, 2016, 07:41:54 am »
Without a doubt I think we can all agree that it is now "A thing of beauty and a joy forever" - amazing job!
VE7FM
 
The following users thanked this post: VK5RC

Offline Cubdriver

  • Supporter
  • ****
  • Posts: 2319
  • Country: us
  • Nixie addict
    • Photos of electronic gear
Re: Restoration / Repair of Tektronix 545 - Finished.
« Reply #74 on: October 08, 2016, 08:05:26 am »
I had quite a bit of luck but Tek made good panels with lettering 'in deep' and good knobs of a sturdy plastic. Good manuals and not weird components in that vintage.
Nothing like putting it up on EEVblog to make you push it along!
I am still so envious of what you guys can get in the USA, so many sellers won't post outside the USA, but it might save me quite a bit of cash and space! HiHi

My understanding is that the markings on those old panels are actually part of the anodization, rather than being silkscreened on as they are on many other instruments.  Because of that, they're pretty bulletproof shy of gouging the panel to the point the anodization is scraped off.

They were definitely very sturdy and well made devices.  It would be interesting to see how much of the plastic fantastic stuff of today will fare over the coming years.

It's a bummer that your options are so limited due to the international shipping issues, but you are correct in that it is likely saving you considerable money and space.  Trust me on that one! :-DD

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf