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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 18th Mar 2023, 7:59 am   #1
Visualimage
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Default Bvm 20F1E fault

Good morning Techs,
I am new to this Group and this is my first post.
I am having an issue with a Bvm20fie and am wondering if any of you have Ben down this road before ?
The fault is a pulsing picture mainly in Horz width . I have re-capped the D board completely and changed the secondary caps on the psu which has not cured this - I have scoped the +B rail and this is flat and steady , but what I have noticed the +6 and -6v rails from psu have slight noise on them ? - so I think the fault maybe on psu?
Anyone been here?
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Old 20th Mar 2023, 11:35 pm   #2
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Default Re: Bvm 20F1E fault

Thatís not a fault Iíve come across before, but these monitors are over 25years old, and weird and wonderful faults are starting to crop up.
Could be bad caps on the ĎEí board, which is where the ĎDí sub board plugs into. Check/replace ones close to heatsink and the surface mount ones, of which there are a handful on there.
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Old 22nd Mar 2023, 10:55 pm   #3
Visualimage
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Default Re: Bvm 20F1E fault

Hi Retrotecie
Thanks for the reply - I might have been going down the wrong path here - this morning I turned it on and it was stable - moved it across the bench and it started to pulse in size - tapping around the flyback and moving the entire lead produces a similar fault - I have tried to remove the entire lead from the transformer but it does not release from within the loptx - question, does the eht lead come away from within the loptx? - like the barco ( you push down and twist to release?)
Also, notice you are bromley based ? So am I ( bromley north) should meet up for a chat
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Old 26th Mar 2023, 10:58 pm   #4
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Default Re: Bvm 20F1E fault

Quote:
Originally Posted by Visualimage View Post
Hi Retrotecie
Thanks for the reply - I might have been going down the wrong path here - this morning I turned it on and it was stable - moved it across the bench and it started to pulse in size - tapping around the flyback and moving the entire lead produces a similar fault - I have tried to remove the entire lead from the transformer but it does not release from within the loptx - question, does the eht lead come away from within the loptx? - like the barco ( you push down and twist to release?)
Also, notice you are bromley based ? So am I ( bromley north) should meet up for a chat
Iím pretty sure the EHT lead canít be removed from the LOPTX (although the twist lock connectors are used on the H stat modules on other models). LOPTX failure wasnít common.
It may just be be a co-incidence that tapping in that area instigates the fault. Itís worth reseating all the boards, if you havenít already and checking the connectors that plug into the motherboards.
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