Sanyo EZ-20 Wobble / Wave Issue

msignor

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Hey Guys,

I figured I would start a new thread considering I fixed the initial issue with this monitor (the image position)

I did a capkit, replaced the filter cap as well. Did NOT replace the b+ pot

My b+ is creeping up ... 3 or 4 volts and I can adjust the hold pots to somewhat stabilize the image to where it looks fine until there is movement... It's tough to not notice the shaking.

That said, It still wobbles especially when there is alot of movement on the screen. Additionally, when I tried to take a video of it happening -- the video came out picture perfect! so I am thinking that it maybe has something to do with the hold pots since when video recorded, it seems to mitigate the image shaking.. is it an illusion?

Question: Common issue with the hold pots? What do I replace with?

Question: Is Q901 the HOT? I happen to have one from a G07 that I never ended up using - am I correct in my understanding that the two monitors share a common HOT? (or same spec)

Per additional reading here, it seems the flyback should be OK. Comments?

I know I have the b+ to replace, and I am sure that will be suggested first I just REALLY don't want to take the thing completely apart again if I can help it.

Thanks,

Matt
 
the H.O.T is Q902 by the fly back.
if you have a full screen and no colaps your H.O.T is good don't mess with it.



Q901 and IC601 are both parts of the VR.
they have to both be good for B+ to work/adjust correctly.

if the B+ pot is faulty it will cause the wave as well if Q901 and IC601 are bad.

they seem to be good as you can adjust the B+ to 108v but the pot may be bad and causing the creep.

Peace
Buffett
 
It's unlikely that the B+ Pot would cause the voltage creepage. Before you take everything apart, I recommend you test the voltage at the main filter cap, to see if it creeps up there. The VR circuit will output a voltage directly proportional to the input voltage.
I have seen a few of the these boards with ropey diodes causing ripple, the same with the main filter cap. At least this is something you can test before completely dismantling.

I would change the B+ Adj pot though, it's useless, replace with at least a 0.5w trimmer pot. I replaced mine with a 22 turn one so you can properly fine tune, the current one seems to adjust about 4volts for every millimeter you turn it :)
 
The filter cap was replaced as part of the capkit I purchased.. I will go and try to see what the voltages are.

On a better note, It did seem like a color issue and I was able to get the game looking mostly normal.. just this damn shake is there even more now.. Seemed to get worse when I turned up the flyback,but could just be my imagination.
 
I don't suppose you have an oscilloscope? Might be handy to take a look at the b+ voltage to see if it is properly filtered, you may have 50/60hz mains waveform making it's way onto the regulated output.

Andy
 
Have not tried w/o the degauss coil... But I managed to replace the B+ pot today and was able to stop my voltage crepe. Solid 108 now.. no change in the shake.

Tried to take a video and capture it the best I can: http://www.youtube.com/watch?v=8J1RqgQJMcU

I have a feeling that it could be the hold POT on the remote board.... I had my buddy watch it as I adjusted and he claimed the shaking stopped, but started immediately as I let go to come and take a look for myself..

So I am going to stop by the local shack or order a POT online and see where that takes me if the degauss coil trick has no change.
 
I'm not sure what game you have but my dk Jr was doing this and I thought for the longest time it was the monitor causing the shaking. It turned out to be faulty pots on the dk Jr PCB. I replaced these with pots from bob Roberts and it cleared up the shakes. Just an idea. If you have these pots, try adjusting them to see if it helps.

edit: I see it is Mario. Not sure if that PCB has adjustment pots or not.
 
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So - Finally had some time here and got the parts needed.

Ended up replacing:

VR351 w/ 10k POT
VR352 & 353 w/ 200k POT
and
VR 354 w/ 50k POT

Seems to have gotten rid of MOST of the wobble.. I have some slight wobble now, but I think it's due to the POTS on the PCB not the monitor at this point. I had the shake after only replacing 351 and 352, so I messed some more and saw it seemed to be a wacky v-size for I went and changed that which seemed to stabilize things.

I am calling this fixed since once everything warmed up, was solid a a rock.
 
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