17-03-2024, 01:16 PM
Thanks Mike that explains it. At first in my naivety I thought the lamp was blown, until I traced the wires.
Frank
Frank
Converting a monitor from 625 to 405
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17-03-2024, 01:16 PM
Thanks Mike that explains it. At first in my naivety I thought the lamp was blown, until I traced the wires.
Frank
17-03-2024, 02:23 PM
Well done. I wonder how many of the ones I've fixed have developed additional faults in storage.
As Mike says, it's a cue light, to show which camera has been selected by the vision mixer.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
17-03-2024, 05:28 PM
I didn't take note of the other leaky capacitor. But I am sure it was 63V 47uF, So most lightly a decoupler on the 27V supply.
It had no visible effect on the display. Frank
17-03-2024, 08:30 PM
(This post was last modified: 17-03-2024, 08:33 PM by ppppenguin.)
I forgot to say that the termination switches are rather unreliable. I would use a T piece and external 75R termination.
Taking out the main PCB is a bit of a nuisance. You have to remove the two connections to the vertical scan coils which is fiddly. Then the PCB can be eased out.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
18-03-2024, 11:42 AM
Looks very good.
Peter
24-03-2024, 11:16 AM
The sync stages have a very wide pull in range. Yesterday I was using a Hedghog PSC and accidentally set the output to 405 lines 60 Hz.
The monitor locked immediately the same as if were on 50 Hz. wouldn't have known only for a change in line whistle and width. Frank
24-03-2024, 03:43 PM
The circuit diagram for these monitors is very badly drafted. Makes it hard to understand how it really works. Fortunately there's a pretty good description in the manual. From memory, the H sync flywheel is quite complex but at heart it's an RC oscillator that will inherently have a wide pull-in range. Frame timebases tend to be fairly unfussy about whether they run at 50Hz or 60Hz though the height may change.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
24-03-2024, 05:48 PM
Hi Jeffrey
I am really impressed with it. I have never seen anything with such a pull in range before. It is great in one way but I must remember to check on something else as well. I have a signal generator with rubbish syncs. On any telly I have tried it on it gives a wobbly picture but the monitor locks to it and gives a rock steady picture. Frank |
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