Sanyo EZ20 vertical bouncing

mrosseau

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Hello,

I have a sanyo ez20 that is bouncing. All the caps including filter have been replaced along with the pots.
B+ is 108.0 VDC. Reflowed 400 section and tested all transistors and diodes. Looked and repaired 3 cracks in chassis. Checked for solder bridges on cap kit. Replaced ic601 la5112n.

Any help is appreciated. Video link below.

http://youtu.be/kscVpRLOCHk
 
check your vertical hold pot.

see if it is cracked or dirty.

look for more cracks.

if you have another GAME PCB try that, or test the monitor in another cab.

that's an odd one, never had that issue.

if you hit a brick wall and need it looked at, your welcome to send it in.

Peace
Buffett
 
Thank you

Thank you for the input. I had already replaced the v hold and v size pots and no change. It also bounces with my signal pattern generator. Also the game board does fine with my original monitor. This is an odd one to me too.

My thought is something in the v hold circuit but since I've put a great deal of time in it I wanted to see if you, Dokert, or anyone else had seen this before.

I'll eventually post a fix or ship it out. Thanks again Buffett.
 
Have you tried the pots on the remote board. Replace all of them. Also check for more cracks just start continuity testing.
 
no prob.

that is where i would go as well.

start in the vertical circuit before the pot and work your way back.

Peace
Buffett
 
Thank you Buffett and mattspad. I'm going to pull the chassis today and look closer for cracks and solder splat and the v hold circuit.
 
no prob.

lets hope it is a simple quick fix.

i have had solder splash hairs before so fine that i did not even see it till i reflowed everything in the circuit.

looking forward to the update.

Peace
Buffett
 
I also have a sanyo that is doing this, as it bounces the voltage is all over the place on the vertical transistors and la1464. if I bring the size down to about an inch vertically it stops bouncing and voltage is stable.
 
theres a bipolar cap that can cause this. I dont recall the value or location though.

brb....
 
maybe some one else can chime in. All I see is C411 in the vertical output section but I dont remember if that cap was the one that causes this.

4.7mf @ 25VDC non polar
 
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