a real challange?

[Kevin Kuehn]

Ordinarily those small test CRT's can be supported by only the yoke on it's tower, with maybe some type of non abrasive clamp on the neck to keep it from sliding forward?

[Yamamaya42]

Originally Posted by Kevin Kuehn

Ordinarily those small test CRT's can be supported by only the yoke on it's tower, with maybe some type of non abrasive clamp on the neck to keep it from sliding forward?

i will try to come up with something

[Kevin Kuehn]

My 5" test CRT had this wedge edge clamp on it when I got it. I'm not sure if that came with these new or was somebody's later solution.

[Yamamaya42]

Originally Posted by Kevin Kuehn

From those pictures it's difficult for me to tell just how bad the video really is. Any chance you have a test pattern DVD?

I understand the struggle of getting to both the top and bottom adjustments. I've been known to roll the whole shebang onto it's side, but only if there's a band holding the CRT secure.

Just for fun here's a couple pictures of me having used my HP8662A synthesized sweeper to align an Admiral 20Z1 chassis. The 8662 has 5 programmable markers and they are being intensity modulated using the Y axis input to the Tek scope. I know it's crazy overkill, but sometimes you need to do absurd things just because you can.

WOW, your o-scope is about as old as mine. :O
but mine is MUCH heavier

[dtvmcdonald]

Originally Posted by Yamamaya42

WOW, your o-scope is about as old as mine. :O
but mine is MUCH heavier

Ah yes. BUT. a question (properly in test equipment, but...)
I have two similar scopes to the one pictured. The add-alt-chop
switch of one does not work properly. Alt and chop work, but add does not.
On the other scope I forget but its clt ot chop that does not work.
Its the identical switch, my scope lacks the digital top row.

Can this be fixed? I've tried to looking inside and did some checking,
but can't tell if its switches, relays, or whatever. Does somebody know
what to do?

[Yamamaya42]

Originally Posted by dtvmcdonald

Ah yes. BUT. a question (properly in test equipment, but...)
I have two similar scopes to the one pictured. The add-alt-chop
switch of one does not work properly. Alt and chop work, but add does not.
On the other scope I forget but its clt ot chop that does not work.
Its the identical switch, my scope lacks the digital top row.

Can this be fixed? I've tried to looking inside and did some checking,
but can't tell if its switches, relays, or whatever. Does somebody know
what to do?

it would be best to know the exact MO# of the scope,
as far as I know, even with scopes this old, it's done with rudimentary logic functions inside the scope and the switch has little to do with it, other to tell it what mode to go in, even my Tektronix 7934 even though it's from the mid 80s, has very complex logic circuits in it.

[Yamamaya42]

that rf signal generator i mentioned will be here wed

now, do I just start with tweaking the replaced coil for the 1st IF, or should I be looking at ALL of them, since it's so old?
and it says use "isolated alignment screwdriver" but most if not all these adjustments are done by turning brass turn screws that move the iron cores, are they not already isolated?

[Kevin Kuehn]

I would only adjust what's known to be replaced, then reevaluate and proceed from there.

I'm not so sure that generator is going to serve you justice. I'm not familiar with it's circuitry, but unless you have a frequency counter it's hard to know how accurate something like that is.

It would be best to use a plastic blade screwdriver, or in a pinch you can sand a flat blade shape on the end of a wooden dowel.

[Yamamaya42]

Originally Posted by Kevin Kuehn

I would only adjust what's known to be replaced, then reevaluate and proceed from there.

I'm not so sure that generator is going to serve you justice. I'm not familiar with it's circuitry, but unless you have a frequency counter it's hard to know how accurate something like that is.

It would be best to use a plastic blade screwdriver, or in a pinch you can sand a flat blade shape on the end of a wooden dowel.

I have 2 "cheap" frequency counters that I used when I was fixing the color problems on my CTC-16LXL, I'm also going to take it work and hook it up to the digital Tek o-scope which has frequency counter in it which is calibrated and check it and my frequency counters against it, to make sure they are all correct.

[Kevin Kuehn]

Originally Posted by Yamamaya42

I have 2 "cheap" frequency counters that I used when I was fixing the color problems on my CTC-16LXL, I'm also going to take it work and hook it up to the digital Tek o-scope which has frequency counter in it which is calibrated and check it and my frequency counters against it, to make sure they are all correct.

Ahh, good plan. You could even mark the dial at the specific frequencies you'll need. One thing I've noticed with low cost AM generators is that they often have all kinds of harmonics, especially on the higher frequencies. In fact they often rely on harmonics to produce some those high bands. Sometimes a good counter can even have trouble sorting that all out.

[Yamamaya42]

YES, audio does work!
https://www.youtube.com/watch?v=I-40z8WvsQs
the WERRRRRRRR you hear in the background is my server, in which are 3 vantec tornado 80mm fans, that sound like a 747 when they start up! :p

[Kevin Kuehn]

It sounds nice and clear. One could always roll off some high end with a tone control hidden under the chassis, but for my hearing it sounds about right.

[Yamamaya42]

Originally Posted by Kevin Kuehn

It sounds nice and clear. One could always roll off some high end with a tone control hidden under the chassis, but for my hearing it sounds about right.

that's NOT the speaker that will go with it when done, obviously I just hooked up a tiny 3 inch 16 ohm speaker from an old color TV for test, I still have the 8 inch jensen speaker that was in the set that still seems to be good after 71 years

[Yamamaya42]

adjusting the 1st IF coil helped a bit, but I still have a lot of RF noise, the B+ getting to the tuner is very low, 99v where it should be 130v i need to replace resistors in the IF bias chain, cause they put the tuner at the END of that chain :/

[Yamamaya42]

https://imgur.com/iju7vXo

umm yeah

i would say that is a big problem

Brown / Green / Brown is 150 ohms... NOT... :O