RE: WG6100 jitters

Yes, they are all over the screen - but only in the X direction. Therefore I
think it cannot be cause by a bad output transistor, then it would be in the
upper or lower half only. It seems to me SOMETHING is pulling the offset
negative but has some problems maintaining this level - breaking down now and
then causing all the distortion. therefore my question - which part can cuase
the DC offset to shift?

I am very curious about these capicators - I have a 327 defl. board but a
first rev. HV unit.

I would very much appreciate it if someone could look this up for me.

Regards,

Mendel

>===== Original Message From vectorlist@synthcom.com =====
>Are the jitters all over the screen? Or are they isolated in a particular
>region? If you search the archives, i have posted in the past about some
>boxy capacitors that when removed, got rid of my Tempest jitters. They
>were pulled by Wells Gardner for no apparent reason between the second and
>third revision of the monitors and were not documented in Woodcock's
>article (although he knows about them and plans to add them to the next
>revision of the doc). With that said, I don't know the locations off the
>top of my head.. Maybe someone can look it up for you.
>
>Fwiw, my problem consisted of jitters just right of center. It was a
>isolated to about 3 inches.
>
>Jon
>
>At 10:14 PM 5/13/2000 +0200, you wrote:
>>Hello Crew,
>>
>>I am having a small problem with my WG6100 Tempest monitor: the screen
jitters
>>in the X direction (mounted in the cabinet this becomes the y direction).
>>
>>The trusty o'scope shows a DC negative offset of about 2 volts at the
>>output of
>>the X amplifier. On this level a high frequency noise is added which shows
>>up as
>>jerky vectors like this:
>>
>>_____/\__/\____ (should be _____________ )
>>
>>This effect shows op on both negative and positive side of the amplifier.
(the
>>screen jitters both at the most upper as lower side, but it is always
positive
>>going as in the example (ie. it is really DC offset noise, the amplitude is
>>always constant).
>>
>>-I have resoldered the whole X amp (actually the whole defl. board)
>>-I have made sure the power supply outputs are nice and flat
>>-I think there are no wirewound resistors because they are the same at the
>>Y amp
>>(and shouldn't that cause amplitude noise?)
>>
>>Can anybody give me a clue here, like which parts can cause the DC offset
>>of the
>>amplifier to behave like this?
>>
>>any help is greatly appreciated because my analog knowledge seizes here...
:(
>>
>>Cya !
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>
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Received on Mon May 15 05:57:54 2000