Mr carlson's curved tracer.

@ovi4 I started watching video 27 and he said go back and view “What Can Old Test Gear Teach Us About Electronics? Find Out.”
Just got done with that video, but kinda put me to sleep. (sorry Paul)
I am glad I did as it was a good refresher for me.

I will be checking out 27, 29, 30, and Videos 58 and 59

I need to take some picture.

Thank you

Mine 

As cab be seen, I have a lot of work to do.

AAs cab be seen there been some hack going on.
Not sure the had a coax connected to the CRT pin.

@ larry_n7luf The scope has been tampered with at some point. It seems that there are quite a few wires that are not originals including that coax. Whoever did those changes must have been a “newbie” Just looked at video 27 but none of the 2 scopes had that coax in them. 

Picture of scope 1 (MCL)

https://imgur.com/2ZgIGwY

Picture of Scope 2 (MCL)

https://imgur.com/qpQ4Yxi

@ovi4 Yes I saw that and they drill a hole in the back for the coax and what was connected to it was cut off.

I like to find a schematic for this unit like MCL had.

That was the only thing I could see, other the capacitor replacement.

I have not put any power to the unit yet, I do not think I will.

Back to the videos

@larry_n7luf if you go here :

https://www.manualslib.com/manual/1572011/Rca-Wo-33a.html?page=2#manual

You’ll get the very same schematic MCL has and more. That is a 12-page “Service manual”. I did not flick all the pages but It must contain the alignment procedure as well.

@ovi4 Thank you, I just downloaded it.

@acockburn Andrew that large resistor, Paul said in the video that it has a lot of heat.
I was wondering if you will have a problem.

I am not sure what I will use for the large capacitor and you did it differently that Paul.

I see you added two terminal strips.

Like to know what you think on what I posted.

Thank you

@larry_n7luf Hi Larry – I think you might be right about that resistor, I wasn’t thinking about that aspect of it – shows I still have a lot to learn 🙂 I’ll revisit it when I put the curve tracer board in – maybe this is the excuse I need to buy a Flir IR camera!

Yours does look a little different, I can’t make out the values on the 2 big capacitors but they could be stock, maybe they ran out of 1000V caps and subbed a couple of 500V in series?

I have no idea what the coax is doing there but the rest of it doesn’t look too bad, I’d put it on a Variac and test it just to see where you are starting from. I test before, during and after – that way if I introduce a problem I have a chance of diagnosing it based on what I did rather than inheriting someone else’s problem.

Yes, I added 2 terminal strips – I think Paul did the same. I soldered the lugs under the screws to ground so I had a reliable connection, moved the power up to one of the new strips like Paul did then figured out the rest.

@acockburn The two large caps are 10MFD at 350VDC.

It should have been part 5uf GMV. 1000 V, I do not recall what GMV means offhand.

I see MCL did not supply a parts list to what he used for this project and I believe he did a serial/parallel of 4 cap, but do not recall the value.

@larry_n7luf GMV is “Guaranteed minimum value”.

Stock, the capacitor should be 0.5mfd at 1000V, not 5mfd, so I am curious what those 2 10mfd caps are doing there. If they were 1mfd in series that would give you the right value, 0.5mfd at 700V which although below spec would probably be just about OK given the voltages shown on the schematic.

Given that Mr C used 4 caps, my guess is that they would be 4 x 0.5mfd @ 600V. If you put 2 in series with 2 in parallel that would end up giving you 0.5mfd @ 1200V which would work just fine.

@acockburn I had been looking at the parts list and it was had to read for what was need and no wonder I could find a 5mfd….LOL

Hope you can see in the picture that it was two 10MFD 350VDC in series. My eye are not that great these days.

I googled and got this So, the question arises, are mFD and µF one and the same thing? The simple answer is they belong to the same measurement scale, i.e., mFD stands for “milli-Farad,” whereas µF stands for “micro-Farad.” There are mostly old capacitors manufacturing companies that are using mFD instead of µF capacitors.

@acockburn Parts list

@acockburn I just enlarged and I see it is a .5uf 

@larry_n7luf You make a good point though, I assumed mFD was micro farad but I could have been wrong lol. Just for fun I checked the old cap that I removed and it measured 0.6 microfarad.

@acockburn I just went back and watched the video and comments and it looks like Mr.C used .47uf 630 volts and used 4 in series/parallel.

What did you use for replacement?

I am now wondering what parts that will no longer be able to get.

I was able to find some parts I got back in 2017 and believe maybe the parts I will need.

I did get ten .47uf 630v caps.