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

[k4pf at juno.com]

Hi, Joe

If you don't have a manual, here is a free one on the 'net:
http://bama.edebris.com/manuals/tek/310a/
It is in  DejaVu format, so you may need an image viewer
like Irfan View or XnView, both available at download.com.

You should follow the signal from the external horizontal
input, and see where it disappears.  It could be trouble
with the horizontal selector switch Sw-210 or the horiz
amplifier tubes V220 v240.  Did you remember to switch
the mode switch to ext horiz input?
  
You an use a 6.3V line from the LV power supply
as a source of horiz input signal.  V220 and V440 should probably
be OK, since there is a controlled deflection using the horiz
position pot.  I assume the pot is near center of its rotation 
for normal mid scale display.

The Simpson 260 is excellent to check HV.
I'm surprised you get no reading with it
at the -1675V check point, even though
you see objects on the screen.  You can check the 5642 filaments
in a dark room this evening.  You can check the Simpson 5KV scale
by connecting to the +300V line.

Have you another scope to work on the Tek?

73,
Ed Knobloch


---------- Original Message ----------
From: "Joseph Orgnero" <josepho at shaw.ca>
To: "Discussion of Electronic Test Equipment" <test-equipment at mailman.qth.net>
Subject: Re: [Test-Equipment] WTD: Help with old scope problem
Date: Fri, 8 Oct 2010 10:53:03 -0700

Thank you Ed for the advice, re your comments. The -150 V is OK, I don't see 
light on the rectifiers but being sosmall is hard to tell, I don't get any 
deflection using the external horizontal input.
As for the HV measurement, I'm using a Simpson 260 on the 5 KV range. Is 
this the right kind of meter>
I'll keep investigating.
73's
Joe
----- Original Message ----- 
From: <k4pf at juno.com>
To: <test-equipment at mailman.qth.net>
Sent: Thursday, October 07, 2010 1:51 PM
Subject: Re: [Test-Equipment] WTD: Help with old scope problem


>
>
> Hi, Joe
>
> Is the -150V correct?  Filaments lit on all 5642's?
>
> Using external horizontal input on rear panel, do you get
> any horizontal deflection?
>
> Do you have another 'scope to work on this Tek 310A scope?
>
> You need a very hi Z meter to look at the HV,
> like a 20K Ohms per volt VOM with a 5KV scale.
> (100 Meg Ohms resistance on that range)
>
> 73,
> Ed Knobloch
>
>
> "Joseph Orgnero" <josepho at shaw.ca> wrote
>>For a number of years Ihave been using a Tek 310A on my bench. I like it 
>>on spite of its age and limited BW because of its small size and sharp 
>>trace. Recently,after not have been used for some months, presnted a 
>>number of problems.
> - There is no horizontal trace, only a spot.
> - The spot can be moved in both directions (V&H).
> - The focus control has only limited effect on the spot.
> - The intensity control has no effect on it.
> - The tubes related to the horizontal and sweep sections check OK.
> - 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.
>
>
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