Having a Vertical Linearity issue...

[PacManPlus]

Hello -

I was hoping someone could help here. I've purchased two of these: https://www.ebay.com/itm/116772811350
However they do not come with the remote boards. They seem to work well, and the seller was great.

I noticed that the boards had a place for Variable Resistors instead of the remote board, and I had a bunch of spare '103's (10k) hanging around, so I put them to use... and I got a picture! (I'm testing it with a standard Pac-Man board).
However, the screen seems to be compressed on the right side. I've included pictures below.
I'm *guessing* that I need a different value of Variable Resistor in the 'V.LINE' place (second in from the left). But I've tried different values for that resistor and nothing seems to help.

I've tried *both* boards, trying to narrow the issue down, but they both do the same thing. I've also tried two tubes, and *they* both do the same thing... so I'm stumped.

In the second picture below you can see how the maze is squished on the right side.
Does anyone have an idea of what to try?

[PacManPlus]

BUMP - Apologies, but I was really hoping someone could hopefully give me a direction to go in. I don't mean to bug, I've just got everything open on my workbench (please).

Thank you so much...

[KPackratt2k]

If you have access to an in-circuit capacitor ESR meter, it may be worth a shot to check the ESR on the capacitors for the linearity circuit to make sure none of them have high ESR.

If the chassis has a linearity coil, try adjusting that with a plastic screw driver.

[MKL]

Check if your chassis follows these schematics, at least the part that is relevant for linearity:
https://ibb.co/tTjyGZCZ

Here the trimmer is 5K but if it's used as variable resistor (wiper = one of the other pins) I don't see how it could do what a 10K (103) doesn't. A 10K would just be more sensitive to movement. Rather, I would change the resistors in series with the trimmer, those corresponding to R414 and R413.

[PacManPlus]

Thank you both for the reply; work has been taking up most of my time but I am going to see what I can figure out.
There is no adjustable linearity coil that I can see; just the pot adjustment that I had to put in (you can see it in the picture).
I'll also look for the resistors in line with the trimmer.
Worst case scenario, I'll post a full shot of the board to see if anyone sees anything obvious.

...at the same time, I'm trying to work on a Baby Pac-Man VIDIOT board that's only giving me two flashes, and I've already done the troubleshooting I've found on the web... So I'm having all sorts of issues

Thank you!

[PacManPlus]

Hey guys, just a quick update: Nothing I do seems to help the situation, so I'm going to take the loss and throw these boards out. I need to find a 13" Chassis that isn't a crazy price.

[PC Engine Fan X!]

Yes, Bally-Midway MFG Co. and Namco of Japan certainly made a lot of money with the Pac-Man/Puck-Man arcade pcbs back in 1980-1981. In fact Bally-Midway was offering arcade operators the opprtunity to get a "2 for 1" deal, by buying a brand new Rally-X cab, he or she would get a brand new Pac-Man cab for free (as some folks weren't so sure about Pac-Man at first when first offered for sale back in November of 1980 of it's initial debut). Eventually, it was the "it" arcade game to have/own as people got bitten by the "Pac-Man Fever" going on at that particular point in time.

Of course, Bally-Midway's release of Ms. Pac-Man in 1981 has even better gameplay than Pac-Man. Super Pac-Man followed the two previous releases in 1982 with the added button of "Speed Up." By 1983, Bally-Midway had released the Pac-Man Jr. cab with it's novel "scrolling to the left or the right" mazes. Namco gave it's blessing to have Atari Games release "Pac-Mania" in the USA with it's new isometric viewpoint + jumping capability + by using Atari's own in-house 4-way digital-based arcade joystick (that was a serious "downgrade" from the better and faster input-wise Wico Command arcade sticks used in the earlier Pac-Man based arcade games).

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Back in 1984, at Disneyland's Tomorrowland's StarCade arcade hangout, there was an uber-rare lone Bally-Midway produced "Professor Pac-Man" arcade cab up and running but nobody was playing it. It wasn't until years later that I learned that Bally-Midway didn't make very many cabs to begin with and thus is considered a rarity within the Pac-Man arcade game genre indeed.
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It's been said that the Pac-Man arcade joystick was none other than a Wico Command type with leaf-based switches as it was super-silky smooth to operate, especially "whipping around the corners" of any given maze.

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It wasn't until Namco released the "Class of 1981 - 20th Year Reunion: Ms. Pac-Man & Galaga" in 2001 as a jamma pcb that has the crazy turbo speed + the ability to continue where you last died + high score saving upon being shut down for the night + a hidden game of Pac-Man included as a bonus -- how cool is that?
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PC Engine Fan X! ^_~