CM8833 MK2 jailbars

[sketchus]

Hi,

Been reading and just enquiring if anyone has any possible solutions to the issue mentioned here:

Philips CM 8533 monitor - dark ghost lines left hand side of screen (picture)

Had this monitor for years and it's always worked ok just with a lot of hissing from the LOPT / flyback Anyway i changed the LOPT this year for a new HR replacement and it works fine apart from the lines as shown in the picture It's only been like this since fitting the new LOPT I've looked...

www.amibay.com

Interestingly my replacement flyback was for a Phillips monitor, using a HR7533 and this issue appears for me too. J can't remember if it was there prior as the monitor was DOA.

 

[roy_bates]

take a good clear picture of yours,and post it here,along with make and model number

hr7533 assumes its a cm8833 mk2 or variant

 

[sketchus]

Apologies, it is a MK2, though you reminded me I actually have a MK1 here. Never had it's flyback replaced - at least I've just opened it up and it appears to be the original. The bars are present on the MK1, however they are MUCH less significant in person, to the point I'd say they only really appear visible on a camera. I've tried to capture photos in the same lighting conditions, the camera really really exaggerates how bad they are. First one is of the MK1, second MK2, and the third is the MK2 again and I've tried to sort of emulate how visible they appear in person.

Also, look how horribly off the colour balance of the MK1 is at the moment. For what it's worth the MK1 needs a lot of TLC, which may be exacerbating the issue on this monitor.

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Image 20240626-204211 hosted on ImgBB

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20240626-205256 hosted at ImgBB

Image 20240626-205256 hosted on ImgBB

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Image 20240626-205435 hosted on ImgBB

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Both monitors have no video source attached.

 

[roy_bates]

on the mk2 check the parts in locations 3522 and 3523 and see if they are open circuit

on the mk 1 check the part in location r427 same deal,as for the green level just turn it down on the neck board

best to have signal going to them,and check for cold solder joints on both on the main board

also,where are you based?

EDIT: actaully,you might have the green switch pressed on the mk1 please make sure its off on the front

 

[sketchus]

Ok, will check those hopefully later today.

Green definitely not been pressed on the MK1.

Someone has already been inside this monitor, the speakers were already disconnected.

 

[roy_bates]

i dont know,but that green switch looks on to me

 

[sketchus]

Trust me it's not I have double checked. The green issue is something else exacerbated in photos. It's definitely tinted though.

 

[roy_bates]

well,lets concentrate on one issue at a time,otherwise itll get confusing as this thread started out with one monitor

 

[sketchus]

Ok, not tested the MK1 yet, but the MK2, there's no open circuit on those components.

 

[roy_bates]

and how did you test them? what measurement did you get?

 

[sketchus]

I ended up desoldering a leg each and testing them. Both were in the 1900ohm range, I think they have a tolerance of 5% so should be in spec right?

Do you want me to test them another way? Sorry if I have misunderstood. I also tested them in circuit with power and signal just to confirm I didnt get an oL reading and I didn't

Also, forgot to mention did a sweep for cold solder and everything seemed ok, but didnt find anything too obvious. I did reflow with some fresh around the rgb input.

 

[roy_bates]

yeah thats right,also dont test parts with power applied for open circuit concidering where they are,they have to be tested out of circuit