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

[k4pf at juno.com]

Hi, Gang

Since some people on the Test-Equipment reflector wish 
to follow this thread, I am posting some of the off-list
correspondence re: troubleshooting the Tek 310A.

Quote:


Hi, Joe

OK, very good.

You didn't mention whether or not you have another scope,
so I assume not.

Using your Simpson set to 250VAC, with black lead to ground,
and red lead connected to "output" terminal of Simpson,
connect red lead to pin 1 of V10.  

Set scope to internal trigger, dc coupling of input and of trigger,
and connect scope input to calibrator.  You should see a big deflection
of the Simpson (maybe 45V).

Assuming you get a strong ac reading, put the red probe
at pin 7 of V40.  You should get the same reading.
(this checks part of the sweep selector switch).

Assuming OK so far, connect the red lead to pin 1 of V40.
You should get around 15VAC reading. (You may have to reset Simpson
scale to 50VAC to read this).

If you still have a signal, please report back and we will continue on.

One other thing, it still bothers me about your Simpson
not showing anything on 5KV scale.  Did you try connecting
it to the +300VDC line when the Simpson is set up for 5KV DC?
(black lead to common, red lead to separate 5KV input of Simpson).
You should see a deflection, not very much, but measurable
as 300VDC.

73,
Ed



>Hello Ed,
Following your comments and suggestions, I went over the scope again
Voltages are OK, but still cannot measure HV?
I have to assume that ther is HV since I'm getting the display and it responds to the 
controls.
Focus has some effect on the trace but not intensity.
With an AC voltage (9 VAC) applied to the H input, the spot becomes a line, so it seems 
that H amplifier is OK
With an AC signal ( 6 VAC) applied to V input, I get a circular pattern (same phase) or 
multiple curves with a different frequency.
When I connect the voltage calibrator, I get two bars with some resemblance to square 
wave, I image due to the low frequency of the H voltage.
Neither time/division not trigger controls have effect on the disply
Tested again the tubes on the time base and trigger sections and they are OK (at least on 
my rather limited tester)
>From the above, it appears that the fault is located on the time base and trigger 
sections.
Any way to narrow it down?
 
Many thanks for your assistance
Joe