The rest was all pretty straight forward- cleaning switches with deoxit, cleaning the bases and tubes and I tested and replaced a few transistors. Matching the specs of the original germanium transistors was tricky but I managed to find a few online.
So after a lot of checking and rechecking I decided to power it up- and straight away cooked a resistor in the LV section! Unfortunately I’d connected one of the caps in reverse but managed to shut it off before any damage was done. So after re-connecting the cap and the blackened resistor it was back up and running.
The time delay tube kicked in on schedule and there was a promising green glow on the screen.
The only problem was that I couldn’t get he trace to appear on the screen and was constantly shown as being below the screen by the neon position indicators.
I don’t have much experience with high voltage stuff- and for this scope low voltage is +500v! So after a few calls I took it to Gerd at Control Electronics here in Sydney. Funnily enough he had his own 500 series scope and a ‘known good’ plugin, so within a day he’d given me a call to say it was up and running!
Apparently one of the germanium transistors I bought online was faulty- and that was pretty much it.
He's a terrific guy- and he sells used test equipment through his site here in Sydney.
http://www.controlelectronics.com.auIt had an issue with the ‘B’ time base which I worked out was a problem with a rotary selector- and that now seems to be sorted.
Then after that the final step was the cosmetic stuff. I stripped the paint with chemical paint stripper, then pressed out the creases and dents, gave it a light sand to get rid of sharp edges and high spots and primed with with etch primer.
I read a lot online about the difficulty in matching the Tektronix paint colour especially in early Tektronix scopes, so eventually settled on 'Krylon Bahama Sea'. It's definitely lighter than the current Tektronix blue- and lighter than the paint on my 564B. But the final result looks half decent so I'll stick with it for the time being.
The final step was to re-chrome the handle clips and the thumb screws that hold the screen hood in place. The scrome had started to chip off so I figured that re-chroming would be the best option. I used a guy in Liverpool, NSW called Luke from Metal Polishing & Chroming. He does terrific work and is a top guy to boot- plus he's happy to have parts mailed to him. Highly recommended!
https://www.facebook.com/pages/category/Automotive--Aircraft---Boat/Metal-polishing-and-chroming-334106321552/So it's all done now- but it does still have a problem with the triggering. I can't get it to hold the waveform so there must be a problem in the triggering circuitry. I don't have a way of testing the tubes yet (which has been very lucky so far) so after speaking to user 'VK5RC' who had also restored a 545- I bought a uTracer on his advice. Here's his post:
https://www.eevblog.com/forum/repair/restoration-repair-of-tektronix-545/msg1018767/#msg1018767I'm yet to build it but I'll test the tubes in the triggering circuit and then I'll go from there. The same problem exists on both the A and B channels so if anyone has any suggestions then I'm all ears!
Anyway I hope this might be of interest to anyone with a similar scope or who's thinking of a similar project.
Cheers, Dom.