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davidcoolman

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Dear all,
i recently experience moving picture on the horizontal axis with my pm1745 on a 29" samsung tube.
picture would go rapidly right then slow down move left rapidly stabilize and would eventually stay still after a moment.
the horizontal sync pot on the remote board is not in cause in my opinion since it operates when the image gets still
any ideas?
note: i use the 24khz

thanks for inputs.
 
well, it could be the remote board horizontal pot since playing with it will eventually stop the horizontal roll.
it seem that only a micro move to the left or right will imediatly move very fast roll to left or right
xhat is the rating of this pot please?
 
pot was within spec but changed without success. the "warming up" phenomenon makes be think of a failing capacitor...
btw the "sub hold" pot on the chasis was damaged. it's been glued so no changes could be made could it be this guy and whats its use anyway?
thanks for ideas
xhat is the rating of this pot please?
5K
 

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I think it only affects 15khz. If you want to replace it, it's a 10K pot.

Personally I would go over the solder joints. However, a recap definitely doesn't go a miss with these chassis. The original caps are almost a quarter century old at this point after all.
 
thanks @nem i'm always worried about "capkits" since jomac was against.
half the people end up with more problems but yeah, thanks, will think of it ?(
best,
 
I have seriously never had any issues after doing a cap kit. However, I don't do "cap kits". I write down the original caps myself and order them from Digikey or TME. I only put in what comes out and always double check my work.
 
thanks so you are ok with the aging cap hypothesis.
i think i'll do the capacitor renewall and will of course double/triple check...
it's gonna take ages... ||
 
There's no harm in replacing the caps. I think your problem is a dry solder joint though. You could try tapping on the monitor when the image starts to scramble. If it fixes it, it's definitely a solder joint issue.
 
thanks. will do.
i should have mentioned that i was planining on doing a cap check but the chassis was so dirty i had to clean it so i could read values. I used isopropyl alcohol and allowed to dry under the warming sun of mediteranean area i end up linving by
afterwards the described symptoms developed,
it could also be because of moving on my not-near-perfect concrete garage floor that caused the solder issue
thanks btw
 
Unfortunately the chassis blew up yesterday. roasted resistor near Q802. possibly more damage.
it will move to the "need fix" to the "for repair" pile
 
So glad I found this post!
Sorry to hear that your chassis blew up @davidcoolman.

I am having a rolling sync problem as well on my Kortek 19" chassis.
I did a full cap replacement a month ago and now it "warms up" (Aka 5 min+ of play) and then the picture rolls like a slot machine just slow.
It worked perfectly until recently.


I tried different PCBs to see if it was just how I had the RGBS setup for that PCB but the issue persists regardless of the PCB.

I was also thinking it was a POT issue on the adjustment knobs (Still haven't ruled this out)
but, I am worried it might be a cold solder join/ crappy solder job on my end. Who knows tbh, never had this issue before with a cap replacement but maybe..

Thanks for the input @nem in regards to dry solder joints.

I am going to try and reflow the solder on the caps/ Chassis to see if that will fix my rolling picture issue.

Do you have any other suggestions besides dry solder joints?
I am hoping there aren't any leaky caps or any poorly connected H,V,Sync connections.

Thanks for posting this!
You have already helped another enthusiast by having this documented.
 
I did a full cap replacement a month ago and now it "warms up" (Aka 5 min+ of play) and then the picture rolls like a slot machine just slow.
It worked perfectly until recently.
You could try hitting the monitor when it starts to roll. Naturally, start first with light taps. If it fixes it, it's a bad solder joint.

If no amount of tapping and or hitting helps the situation, then it's possibly a component that's breaking down. A resistor or diode maybe.
 
Thank you! I traced it back to a dried out h-hold trim pot.

If I touch one leg of the pot it sends it rolling.
If I bridge both sides of the pot with my fingertip it sends it rolling really fast.

I reflowed the solder on these pots and it slowed the roll down (lol slowed it's roll)

But, I am getting a few 5k, 10k and 300 ohm pots to replace these old trim pots.

I hope that fixes it. :)
 
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