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

Mon Oct 11 14:40:04 EDT 2010

Yup. Had to be.

Best,

-John

===========

> Thank you John,
> I figure out that the problem is on the meter, I cannot get readings using
> a
> different voltage source.
> I'll worry about this later.
> Joe
> ----- Original Message -----
> From: "J. Forster" <jfor at quik.com>
> To: <louisianaparanormalsociety at yahoo.com>; "Discussion of Electronic Test
> Equipment" <test-equipment at mailman.qth.net>
> Sent: Sunday, October 10, 2010 7:43 PM
> Subject: Re: [Test-Equipment] WTD: Help with old scope problem
>
>
> A Simpson 260 appears to be 20,000 Ohms/volt, so on the 5000 V scale the
> input impedance is:
>
> 5000 V x 20,000 Ohms/V = 100,000,000 or 100 Megs.
>
> -John
>
> ==============
>
>> Use a Digital Voltmeter with an impedance of 10 meg ohms or
>> higher. David
>>
>> --- On Sat, 10/9/10, Joseph Orgnero <josepho at shaw.ca> wrote:
>>
>>
>> From: Joseph Orgnero <josepho at shaw.ca>
>> Subject: Re: [Test-Equipment] WTD: Help with old scope problem
>> To: "Discussion of Electronic Test Equipment"
>> <test-equipment at mailman.qth.net>
>> Date: Saturday, October 9, 2010, 11:41 AM
>>
>>
>> Thank you Ed,
>> I do have the original manual, so I'm OK that way.
>> As for the HV, some other messages state that the 260 is not suitable
>> due
>> to
>> loading, unfortunately, I don't have a VTVM for that purpose.
>> I'll follow your advice and go over the scope again, hopefully, I shall
>> be
>> able to narrow down the problem.
>> I'll keep you posted.
>> Joe
>> ----- Original Message -----
>> From: <k4pf at juno.com>
>> To: <test-equipment at mailman.qth.net>
>> Sent: Friday, October 08, 2010 1:15 PM
>> Subject: Re: [Test-Equipment] WTD: Help with old scope problem
>>
>>
>>>
>>> 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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>>>
>>>
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>>
>>
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