Have we a resident CUB monitor expert?

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
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Bat
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Have we a resident CUB monitor expert?

Post by Bat » Sun Mar 18, 2018 7:14 pm

Hi,
I've got a monitor here with no picture on it :(
It makes the usual TV noise when switching on, so I'm guessing the HV side is ok?
Are there any common faults or things that are easy to test? Internal fuses look ok...
Thanks in advance :)
Cheers,
Gavin :)

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1024MAK
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Re: Have we a resident CUB monitor expert?

Post by 1024MAK » Sun Mar 18, 2018 8:03 pm

Does the heater in the rear of the tube glow?

Do you see anything if you turn up the user contrast control to maximum?

Mark

Bat
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Re: Have we a resident CUB monitor expert?

Post by Bat » Sun Mar 18, 2018 9:07 pm

Hi,
Heater glow, check :)
Contrast control, no change :(
Screen part of tube becomes statically charged when on, you can see and hear it. If that means anything?
Cheers,
Gavin :)

zeem
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Re: Have we a resident CUB monitor expert?

Post by zeem » Sun Mar 18, 2018 10:28 pm

Would the service manual help? There seems to be some troubleshooting steps that might be relevant on page 37.

http://stardot.org.uk/mirrors/www.bbcdo ... nitors.pdf

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Slo
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Re: Have we a resident CUB monitor expert?

Post by Slo » Sun Mar 18, 2018 10:37 pm

Is there any light showing on the screen, have you tried it in a dark room to make sure?

Could be a tripler problem, is it whining at an unmistakable audible level?

Bat
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Re: Have we a resident CUB monitor expert?

Post by Bat » Sun Mar 18, 2018 11:28 pm

Hi,
Slo... Nothing in the dark not a light or a sound, just that surge of HV sound when you switch it on.
In my non-expert capacity I'd say it's a problem at the input stage as my gut feeling is everything works except it's not processing the input signals?
Cheers :)

Bat
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Re: Have we a resident CUB monitor expert?

Post by Bat » Mon Mar 19, 2018 10:12 am

Hi,
A bit of reading this morning has given me a thought.... Uh oh! :roll: :lol:
Is there any way of testing the monitor other than with a beeb?
The reason for asking this is I don't think the composite output is 100% right and the RGB socket uses the composite as a sync signal I've read.
Would this prevent me getting a picture or should I at least get some sort of mess on the screen?
Cheers,
Gavin :)

Bat
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Re: Have we a resident CUB monitor expert?

Post by Bat » Mon Mar 19, 2018 10:56 am

Hi,
just thought I'd add a picture,bit concerned about the white deposits on the presets...
Cheers :)
IMG_20180319_104634.jpg

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