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Vintage 500 Series Tektronix scopes

Tony L

Tony L

Administrator
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Today I saved these two lovely vintage Tek valve scopes from meeting a skip. A 543B and a 533A. I’ve absolutely no idea of their functioning condition. My hope is I can maybe given time get one nice one out of the pair. I took one stand, the one furthest away in the pic as it is a proper Tektronix one.

This thread is just a statement of intent as this will be a restoration projecr that may well take me years! It is obviously way, way over my current technical ability, but that is how one learns new tricks.

My initial strategy is to do some thorough cleaning as they are absolutely filthy. Really crazy dirty and full of crap. After that I’ll stick them each on my dim-bulb tester and see if either has any life at all, but this is likely weeks or months off. Annoyingly I don’t even have the mains leads. I can theoretically power up the 533 as that is a Bulgin, but not the 543 as that is some other weird thing I need to identify (it is not a Bulgin or IEC). It has a round ground pin and flat live and neutral.

First I clean. There will be a lot of cleaning in this project.

PS The stand is coming up pretty well. I just hosed it down in the back yard as the weather is so hot it will dry real quick. I’ll buy a proper dust-blower before even starting on the scopes.
 
The weird connector is actually a fairly standard american type, I can`t remember the name but they shoud be avail able fairly easily.

Do not be tempted to run the mainframe without the vertical plug-in, a loading resistor will burn out.

Be very careful if replacing components on the ceramic tag strips, too much heat or the use of too much standard solder will strip the silver metalisation from the ceramic. Tektronix used to supply a small reel of the correct low melting point silver bearing solder mounted on the rear panel but these are likely to have dissappeared after sixty odd years.

If you have power supply problems fix the -150 volts first, all the others are referenced from it.

They chuck out about 500 watts of heat, you may not want to run them for long in this weather.

You should have a lot of fun to come, good luck.
 
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Ok, so what are we calling these things? This is actually the back of the stand. I need to buy a mains cable for the 543B, so I’ll be needing a cable that ends in the type female socket of which there are three shown in the pic (back of the scope has the prongy thing).
 
stonehenge said:
I used to calibrate those back in the day. The HV side could give a kick :)
Click to expand...

Do you take on calibration job? I've got a HP3580A spectrum analyser and a Tektronix 465B 'scope here that I'd like to get recalibrated at some point.
 
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Much, much cleaning. The stand is about as good as it can be now. I totally soaked it in the back yard yesterday and gave it a good scrub. It was so hot out it dried off fast. I then took the wheels of and soaked them in a washing up bowl whilst cleaning everything with Servisol. Its as good as it can be now. A fair bit of age ‘patina’ but all the utter filth is gone.

I then moved to the case and front panel of the 543B. Again absolutely filthy and these knobs having such deep grooves are a PITA to clean given just how filthy they are. I removed them all and soaked them and then went at them with a toothbrush. It’s looking pretty good. I’ve not done the plug-in yet.

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Here’s a look inside. Again absolute filth, but the build quality is just astonishing. The one clean shiny valve is a Mullard ECC82 which I pulled as I understand Mullard date codes. It’s 1966. One day all the valves will be that clean!

I ordered an air-blower (Amazon) so I’ll soon be able to blow much of this filth right across my back room (I’ll try and lump it out into the back yard for this).

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This 543B appears to have had a modification at some point. I obviously don’t understand this at all, but I’ll leave it be for initial testing unless anyone suggests otherwise. If it is easy to reverse-out I’ll attempt that later once I better understand what the hell it is and what it was there to do. If anyone understands what it might be please speak up!

PS At some point in the future one of these scopes will be up for grabs. My aim is to try and get one tidy looking working one for myself, but that done the other can be had for free assuming the interested party collects. This may be months or a year off, but long-term I don’t have space for two. I only took both as I had no idea if either works (I still don’t) and didn’t want to risk taking a dead one and skipping a working one! I can also be OCD in picking the nicest case parts etc, but there isn’t much between them.
 
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I think those tall B9A valves in between the 6080s are 6CW5 / EL86 - if you need spares let me know.

I would expect that the mod would only affect Z mod operation.
 
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Giving the CA plug-in a clean. I’ve just tested the four 12AT7s on my little Orange tester and three come up good, one ‘worn’ (but likely still ok as it was reading the same strength as ‘good’!). I can’t test most of the valves in this thing as the little Orange tester is limited to the most popular guitar amp valves (and annoyingly no rectifiers). One of the 12AT7s had obviously been replaced as it was a mid-70s late-logo Mullard. The others were 60s black-plate Brimars.

If both plug-ins work I suspect this won’t be the one I keep as it has ancient screw-fit probe sockets and I have no suitable probes. The other plug-in, a solid-state Type 1A1, has standard BNC connectors so should be fine with the RS probes I have for my usual Hameg scope.
 
The 1A1 plug-in is far superior to the CA but it is not entirely solid state, the input stages use nuvistors.

BNC to SO-239 adaptors are readily available.
 
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The blower I linked to above turned up. It is seriously powerful, just way, way better than the air in a can stuff. It gets the crap out for sure. Obviously some grime, nicotine glaze or whatever will remain, but I’m not going to go crazy about that. If I can get everything in the scopes to this level I’ll feel happy enough powering up on a dim-bulb.

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Cosmetically this one is looking pretty nice now. Far better than I was expecting given it was covered in Dymo labels, stickers and just so much utter filth. The case is getting there too. I’ve got the hand painted and stencilled lab branding mainly off now, which surprised me as I feared I’d be stuck with that. Servisol Foam Cleanser 30 allowed to sit for 30 minutes or so is certainly breaking it down.
 
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Mike P said:
Do you take on calibration job? I've got a HP3580A spectrum analyser and a Tektronix 465B 'scope here that I'd like to get recalibrated at some point.
Click to expand...

Sadly no. I moved out of the Calibration lab in around 1988 as I progressed into supervising and management. I still miss doing this work but I would be rubbish at it now; shame as I calibrated some high end kit like Scopes and Spectrum Analysers. But my speciality was powered waveguide and radar outputs that used to fizz and crackly with KVolts at ultra high frequencies. I once got a 3Kv kick from a piece of powered waveguide that had an earth fault. That took me off my feet and threw me across the lab.
 
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A bit more cleaning done. Every valve removed, cleaned and replaced. The few I can test seem ok. The act of doing that should help the valve bases make good contact. I need to have a look at the fan bearings and then, once the mains lead arrives (which may be next week), I think I’m ready to power it up and see what it does.

PS Pretty amazed I managed to find a couple of 500 Series scopes in the wild outside of Mr Carlson’s Lab:

 
stonehenge said:
Sadly no. I moved out of the Calibration lab in around 1988 as I progressed into supervising and management. I still miss doing this work but I would be rubbish at it now; shame as I calibrated some high end kit like Scopes and Spectrum Analysers. But my speciality was powered waveguide and radar outputs that used to fizz and crackly with KVolts at ultra high frequencies. I once got a 3Kv kick from a piece of powered waveguide that had an earth fault. That took me off my feet and threw me across the lab.
Click to expand...
Well I'm sure you'd be much better at it than me!
 
15 years ago I used to see these old 'scopes routinely in thrift stores for almost no money, as Tektronix is local-ish. Rarely see them now, maybe a couple a year. Spent many hours staring at one in grad school. This thread is a nice combination of nostalgia and PTSD.
 
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