WG4900 Help ID this mod

i have seen it and fixed those chassis before.

but i have never had them running together next to each other to tell if there was any real difference.

sorry if that offers no help.

Peace
Buffett
 
i have seen it and fixed those chassis before.

but i have never had them running together next to each other to tell if there was any real difference.

sorry if that offers no help.

Peace
Buffett

I got it up and running, but it's the first time I've seen the modification. Am I right in assuming it's for increased width adjustment?
 
possibly i would need one in front of me to trace the circuit.

it apears to help the linearity due to having a coil in line with the two poly caps.

they're values suggest they are in the vertical circuit due to their low uf and v ratings.

Peace
Buffett
 
4900 Mod

When I have seen this modification, it has been used for screen width adjustment, instead of swapping out polypropylene capacitors of different value, could example is Moon Patrol. If you trace the wires going to the pcb they should be going to C365. You can use the mod or remove it completely and insert the correct cap at C365.

Thanks
Greg
 
possibly i would need one in front of me to trace the circuit.

it apears to help the linearity due to having a coil in line with the two poly caps.

they're values suggest they are in the vertical circuit due to their low uf and v ratings.

Peace
Buffett

Definitely in the horizontal circuit. Tied to the HOT and traces on the width coil. There is an adjustable coil for width adjustment.
 
When I have seen this modification, it has been used for screen width adjustment, instead of swapping out polypropylene capacitors of different value, could example is Moon Patrol. If you trace the wires going to the pcb they should be going to C365. You can use the mod or remove it completely and insert the correct cap at C365.

Thanks
Greg

Yep,
These were used in Moon Patrol (and probably Motorace USA). Without the mod, the image is horizontally tiny.

Edward
 
thanks you elutz.

now i know when i work on theses chassis and the image is off with my test rig i know what games they were used in and that it is normal for the image to be off.

you learn something new every day.:)

Peace
Buffett
 
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