Author Topic: Restoration / Repair of Tektronix 545 - Finished.  (Read 16154 times)

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Offline VK5RC

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Restoration / Repair of Tektronix 545 - Finished.
« on: September 04, 2016, 12:26:00 pm »
I found a Tek 545 for sale on eBay that was quite close to me (the postage on 30kg is not cheap) and the price was pretty good. No major bits missing no major trauma.
I have posted a bit of my work to date on Martin.M s excellent Tektronix repair thread but thought I should give this beast its own thread.
I appreciate the guidance I have received from Martin.M and other EEV bloggers.
The front picture looks really good but open the side covers and find 2016-1957 years of dust . a little bit of surface rusting but nothing serious.
« Last Edit: October 08, 2016, 03:30:10 am by VK5RC »
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Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #1 on: September 04, 2016, 12:39:16 pm »
A rough plan to tackle
Vacuum out the bit bits and most of the free dust
Start at the top of one side (RHS) cleaning  with mainly IsoPropyl Alcohol swabs / cotton buds (Q tips)
Cleaning tube tops with distilled water, bases with IPA
Rusty bolts (only a few) remove,  brass brush then a very light smear of Gun Oil (Braek Free LP) for rust prevention
Aluminium chassis - IPA clean with cotton rag then also a very light rub with Gun Oil
Test tubes ; using uTracer from dosforever - a great kit , http://www.dos4ever.com/uTracer3/uTracer3_pag0.html
Test major filtering capacitors
Clean / remount fan - rubber suspension had perished
Clean / test plug In.
Final voltage rail testing
Switch on
Fault tracing
Front panel tidy up
Chassis repair / respray

Edit; I keep thinking of things I will need to do!!!
« Last Edit: September 04, 2016, 01:10:37 pm by VK5RC »
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Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #2 on: September 04, 2016, 12:44:17 pm »
The RHS of the Tek 545 has inside the chassis a pivoted subframe or 'door' that swings out giving pretty good access to the large number of tubes. Lodged near the base of a tube I found a piece of wire, not sure if it had done any mischief.
The tubes are found not only on the base of the chassis facing up, the 'door' facing in but also the roof facing down!
Below is a photo of the RHS after a fair bit of cleaning.
Whoah! Watch where that landed we might need it later.
 

Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #3 on: September 04, 2016, 12:49:37 pm »
After a lot of cleaning, needed a bit of a break so I tackled the fan. I was sup prised to be able to find a very close fit from my local RS components supply house.
Fan powers up with 110v AC, some silicon oil (thanks Martin.M) ordered .
Whoah! Watch where that landed we might need it later.
 

Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #4 on: September 04, 2016, 01:04:31 pm »
The tube testing has been a bit of a learning curve for me as I haven't used tubes in seriousness.
The uTracer is basically 3 computer controlled switch mode power supplies 1 for the heater and can supply an Amp or two and two high voltage SMPSU. These can supply 350v DC for the few milliseconds each test is carried out. This allows a lot lower power input, lower thermal stress on the tube under test and as the high voltage isn't around for long the opportunity to electrocute yourself also goes down! The uTracer can measure the current supplied as well as the voltage and graph / trace the results
You have to find the various types of tube sockets needed and wiring them is a challenge (see photo below), fortunately the pin numbering system of tubes NEVER changed.
A peg board is required to link the heater to the correct pin number, I followed the uTracer kits suggestion of colour coding the wire but also making a little card to reduce pegboard errors.
Finding the data sheets wasn't too bad.
A photo below shows a tube test and my paper log of the valves tested and the result.
One of the power twin triode voltage regulators (6080) has a dud side and I think one of the smaller signal type twin triode 6BQ7 had been replaced by a 6DJ8 I think (the number has come off but the gain was way too big)
« Last Edit: September 04, 2016, 01:08:34 pm by VK5RC »
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Offline matthieu.e

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Re: Restoration / Repair of Tektronix 545
« Reply #5 on: September 04, 2016, 02:06:13 pm »
Hi,

That is a very nice scope with all the tubes ! :-+ Your restauration seems to be in the good way.
All the functions of your scope are OK ?

I have an analog scope, a little Hameg HM 307 in addition to my digital DSOX20002A. I don't know why but I am attached to the HM307 and want to keep it.


I see you have a U tracer ? What is your opinion on it ?
I plan to buy the U tracer or to make one myself using variable power supply and Matlab script. I would like to match tubes when I work on audio amplifier.

Could you present us your work bench ?  :)

« Last Edit: September 04, 2016, 02:15:01 pm by matthieu.e »
 

Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #6 on: September 05, 2016, 12:02:54 am »
Hi matthieu.e
My semi -recent work bench photos are in the post https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/2109/
   reply no 2109
While the uTracer is not cheap, it is very well made, includes firmware in the PIC, a professionally made PCB, I think its designer is an EE. The PC based software works well with a USB to serial interface (note one type of USB/Serial chipset is preferred). If I blew it up today I would get another for sure.
I certainly would not be able to make something of similar quality esp for the price. The manual is good as well. You have to allow some extra money for a box but also the tube bases are not cheap, I went for as many as I could find on the assumption that after I made it , I would be very reluctant to add more. I think it works well, a lot better than most "tube testers".
I am not an EE but an enthusiastic Amateur radio op, and have done a bit of restoration, partly as I like some of the older gear but also as a learning exercise. i have repaired / restored an HP 5245L, a Tek 453, , HP 5342, and a few others.
I note you like your Hameg gear, some of the older gear has a better user interface, for example my HP 3314 is my go to frequency generator as it is so intuitive to use and I often don't really need the higher precision of the newer gear.

The Tek 545 is still in the repair phase so I haven't switched it on yet as that could be a bad experience. As I work, have family etc it may be some weeks before I get to that stage.
regards Rob



« Last Edit: September 05, 2016, 12:57:08 am by VK5RC »
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Offline FlyingHacker

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Re: Restoration / Repair of Tektronix 545
« Reply #7 on: September 05, 2016, 02:40:54 am »
Looks like fun. I recently did a 564.

I replaced all my electrolytics with modern caps. If you do that don't make my mistake of forgetting to ground the negative pins to the chassis where appropriate (when the original was case grounded).

All my pots needed electro solve AND CRC-26 to get smooth.

Dunno about the 545, but my 564 has some HV (-3000V) outside the HV can. I got too close to that and took a nasty hit on my hand... Keep on hand in your pocket :-+
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Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #8 on: September 05, 2016, 11:53:31 am »
@FlyingHacker
Thanks for the comments, I am seriously chicken when it comes to anything over 100V. I recall the 545 is in that HV range.

I have tested quite a few of the can type capacitors on the RHS and all had ESR <0.2 Ohms, Martin.M comments in his Tek repair post the Tek Caps are pretty reliable :-+ At this stage I will go with those caps at switch on. Will check for ripple etc.

My unit is dirty / dusty and I think has old cigarette smoke residue for good measure but otherwise not too bad, all the pots and switches mechanically turn nicely. Electrically who knows, but I figure a good clean and test of tubes and caps before has to help the electrical odds in my favour .
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Offline richnormand

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Re: Restoration / Repair of Tektronix 545
« Reply #9 on: September 07, 2016, 03:23:22 am »
Nice resto job on a worthwhile instrument. :)

I got a Tek 545A with about 10 plug-ins (including the fast risetime one with the mercury relay for calibration and adjusting the delay line) about 40 years ago, surplussed when A.V. Roe (Avro Arrow) got creamed. Fully restored then. Loved the ceramic rails with silver solder and the fact they included spare solder for future repairs inside the unit. Also came with full manuals.

It still works today and in used occasionally when doing high voltage or risky stuff for semiconductors scopes. Great to warm up the basement in winter with it's nearly 50 tubes. These front-end tubes can take a beating and still go!

Let me know if you need inside photos, tube pinouts or specs or measurements to help the process.
« Last Edit: September 07, 2016, 03:46:10 am by richnormand »
 

Offline Alex Eisenhut

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Re: Restoration / Repair of Tektronix 545
« Reply #10 on: September 07, 2016, 09:21:30 am »
Nice resto job on a worthwhile instrument. :)

I got a Tek 545A with about 10 plug-ins (including the fast risetime one with the mercury relay for calibration and adjusting the delay line)

Great scope, but what plugin is that? Type N?
 

Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #11 on: September 07, 2016, 12:25:53 pm »
@richnormand lovely photo,  mine is the plain 545 so the screen only has 4 vertical divisions,  I really appreciate the offer of support,  I will try not to bother. 
Work and family commitments may slow me down.
Regards Rob
Whoah! Watch where that landed we might need it later.
 

Offline richnormand

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Re: Restoration / Repair of Tektronix 545
« Reply #12 on: September 07, 2016, 03:28:02 pm »
@richnormand lovely photo,  mine is the plain 545 so the screen only has 4 vertical divisions,  I really appreciate the offer of support,  I will try not to bother. 
Work and family commitments may slow me down.
Regards Rob

Actually it has only 4 vertical divisions. I replaced the graticule plexi with this one to get red backlight and a more uniform light when I was using the camera. I still have the original one though.
 

Offline richnormand

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Re: Restoration / Repair of Tektronix 545
« Reply #13 on: September 07, 2016, 03:34:07 pm »
Nice resto job on a worthwhile instrument. :)

I got a Tek 545A with about 10 plug-ins (including the fast risetime one with the mercury relay for calibration and adjusting the delay line)

Great scope, but what plugin is that? Type N?

It's a Type 53/54C
 

Offline Martin.M

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Re: Restoration / Repair of Tektronix 545
« Reply #14 on: September 07, 2016, 04:39:19 pm »
53/54C is the early version of the CA,
most of application of them both is identical.
They are good for up to 30mc, inside are 15 tubes working  :) The typical probes are a pair of P6006

Early plugins (and scopes) use oftenly the UHF plug, PL259 instead of the BNC. The P6006 Probes also. It is a good idea to have some adaptors PL to BNC in the house  :)

Rich you have also the little 305DMM there, very nice to see a living one  :)

I am interested to a picture from that scope mobil "lab cart" never seen that.
The typical scope mobil of 545A and relatives is the Type 202-2 (with a housing for 2 plugins to swap)

greetings
Martin
« Last Edit: September 07, 2016, 04:48:49 pm by Martin.M »
 

Offline richnormand

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Re: Restoration / Repair of Tektronix 545
« Reply #15 on: September 07, 2016, 05:14:49 pm »


Rich you have also the little 305DMM there, very nice to see a living one  :)



The 305 gets a fresh set of NiCad every 5 years or so. Used when I need to float a scope for HV work. A few months ago I used it to adjust the PWM tracking extractor voltage for a CW x-ray tube. Just have to make sure it is well isolated on about 4 cm of dry plywood and all wires setup and isolated properly before turning on the machine. Nice and dependable portable unit.

« Last Edit: September 07, 2016, 08:46:12 pm by richnormand »
 

Offline Alex Eisenhut

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Re: Restoration / Repair of Tektronix 545
« Reply #16 on: September 07, 2016, 11:40:37 pm »
Nice resto job on a worthwhile instrument. :)

I got a Tek 545A with about 10 plug-ins (including the fast risetime one with the mercury relay for calibration and adjusting the delay line)

Great scope, but what plugin is that? Type N?

It's a Type 53/54C

Yes, but I meant this part :

including the fast risetime one with the mercury relay for calibration and adjusting the delay line
 

Offline richnormand

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Re: Restoration / Repair of Tektronix 545
« Reply #17 on: September 08, 2016, 02:12:09 am »


Yes, but I meant this part :

including the fast risetime one with the mercury relay for calibration and adjusting the delay line

Ha! sorry about that.

It's type 53/54P Plug-in Test Unit fast rise-time mercury pulser.

Here are some pictures.

Front panel.

Inside panel is at 45 degrees so it will work with the scope upright and on its side.
Inside photo shows the schematic diagram and supply.
Second inside photo shows the electro-magnet to actuate the mercury reed switch.

Once you see the distributed tubes (valves) in parallel for the vertical deflection in the scope and the insane number of adjustable trims in the transmission line between them you will see how this plugin was most useful when you changed several tubes for a good match.

« Last Edit: October 03, 2016, 07:23:02 pm by richnormand »
 

Offline Alex Eisenhut

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Re: Restoration / Repair of Tektronix 545
« Reply #18 on: September 08, 2016, 02:17:50 am »
Yoicks! I've only seen that called the Type P. I see now. You can get the TU7, it's better, has more thingies on it.
 

Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #19 on: September 08, 2016, 11:40:09 am »
Serious "Plug In Envy"  happening here; better get  my old girl working first :-+
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Offline VK5RC

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Re: Restoration / Repair of Tektronix 545
« Reply #20 on: September 10, 2016, 07:32:48 am »
Working on the top HV supply, found the main filter caps (10uF)  for the 150, 350 V rails has an ESR of 15ohms or so, Have ordered some new caps and will prob do the 'hide them in the old can' trick. May explain why one side of one regulator tube (6080) had sold out
Below are the before and after of the LHS, all tubes tested OK.  Big fan now of window cleaning liquid first then Isopropyl alcohol. (Thanks Martin.M) :-+
Whoah! Watch where that landed we might need it later.
 
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Offline Martin.M

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Re: Restoration / Repair of Tektronix 545
« Reply #21 on: September 10, 2016, 01:00:41 pm »
looks fine  :)

Tip: when the part No from a tube begins with 154 its a tube, is there a 157 in begin, it is a selected tube.
do not swap tubes by cleaning, they have to go in the socket where they comming from.

6080, is mostly OK, oftenly I found tired 6AU6 or a tired 12AT7, 12AX7 in the PSU, the driver stages from the 6080 are hard working parts.
greetings
Martin
 

Offline Cyberdragon

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Re: Restoration / Repair of Tektronix 545
« Reply #22 on: September 10, 2016, 01:02:51 pm »
Below are the before and after of the LHS, all tubes tested OK.  Big fan now of window cleaning liquid first then Isopropyl alcohol. (Thanks Martin.M) :-+

Did you wash the tubes?! That means you washed off the silkscreen on them! :palm:

EDIT: it looks like some of it survived, just be careful cleaning tubes.
« Last Edit: September 10, 2016, 01:13:09 pm by Cyberdragon »
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Offline Alex Eisenhut

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Re: Restoration / Repair of Tektronix 545
« Reply #23 on: September 10, 2016, 01:38:49 pm »
Below are the before and after of the LHS, all tubes tested OK.  Big fan now of window cleaning liquid first then Isopropyl alcohol. (Thanks Martin.M) :-+

Did you wash the tubes?! That means you washed off the silkscreen on them! :palm:

EDIT: it looks like some of it survived, just be careful cleaning tubes.

Only some tubes have water soluble markings, usually it's etched into the glass. Unfortunately, it's the nice looking ornate logos that wash off.
 

Offline FlyingHacker

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Re: Restoration / Repair of Tektronix 545
« Reply #24 on: September 11, 2016, 12:17:52 am »
Yeah, I washed a lot off mine by mistake... It took me two or three to notice.  |O  Oh well. Not much I can do now.
--73
 


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