[Test-Equipment] WTD: Help with old scope problem

[Joseph Orgnero]

Hello John,
Thank for taking your time on this.
I hope the comments below answer your questions. I went over the scope 
again, results:
- LV voltages are OK, but still cannot measure HV, however, I assume is ther 
since I have a display (dot) and can move it in both directions.
- Focus has some effecto on the trace but not intensity (strap on rear OK)
- With  9 VAC applied to the H input on the back, the spot becomes a line, 
so, I assume that the H amplifier is OK.
- With  6 VAC applied to the V input, I get a circular pattern (same phase) 
and multiple patterns with a higher frequency.
- With the voltage calibrator connected to the V input, I get two bars with 
some hint of a square wave. I image due to the low frequency of the H input. 
Both voltage controls (V and calibrator) displace the bars.
- Neither time/division nor trigger controls have effect on the display.
- Tested again the tubes on the time base and trigger sections and they are 
OK (at least on my limted tube tester)
- From the above, I assume that the problem is located on the above 
sections.
- Any way to narrow it down?

Many thanks for your assistance
Joe
----- Original Message ----- 
From: "J. Forster" <jfor at quik.com>
To: "Discussion of Electronic Test Equipment" 
<test-equipment at mailman.qth.net>
Sent: Saturday, October 09, 2010 11:14 AM
Subject: Re: [Test-Equipment] WTD: Help with old scope problem


> Hi Joe,
>
> OK. I now have and can view the prints. See questions below:
>
>
>>>>>> >- There is no horizontal trace, only a spot.
>>>>>> >- The spot can be moved in both directions (V&H).
>
> Can the spot be moved from off-screen left to off-screen right?
> Ditto V spot?
>
>>>>>> >- The focus control has only limited effect on the spot.
>
> Will it focus to a good spot?  Does the Astigmatism control work?
>
>>>>>> >- The intensity control has no effect on it.
>
> Is the CRT cathode jumper (rear panel) in place?
>
>>>>>> >- The tubes related to the horizontal and sweep sections check OK.
>
> Have you checked all the regulated Power Supply voltages?
>
>>>>>> >- There are no broken, burnt or overheated components.
>>>>>> >- LV voltages are OK but I cannot get a reading on the HV test point
>>>>>> (5642 rectifiers).
>>>>>> >- If I apply a signal from the voltage calibrator, the spot splits
>>>>>> on
>>>>>> two.
>>>>>> >Any suggestions as to the cause of these problems (and fixes) will
>>>>>> be
>>>>>> greatly appreciated.
>>>>>> >Thanks
>>>>>> >Joe Orgnero  VE7LBI
>
>
> Best,
>
> -John
>
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>
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