Arcade Collecting > Merit/JVL Touchscreen
Horizontal size is too large and won't allow me to change
Ken Layton:
Merit used some two dozen different makes and models of monitors in the Megatouch line. Anything could be in there. I've also found in some cases Merit mislabeled the cabinets and/or the monitors installed. Some game cabinets had a paper label near the machine power cord that would say for example, "Type 66" to indicate Merit type 66 monitor was installed. This was so you did not have to open the case and remove the monitor to find out what it was. Naturally you could not rely on that label to be correct because operators would swap out monitors to keep the machine running.
In general, if the picture width will not adjust, then the electrolytic capacitors on the monitor main board are likely the cause. They will need to be replaced. You will need to remove the monitor from the cabinet to recap the monitor. Remember, the airflow in these machines is poor and the heat literally bakes the electrolytic capacitors so it's a good idea to replace them all.
shiori1425:
Hey guys, I've done a cap kit on the monitor Chassis and neck board now. I even replaced a few of the electrolytic caps that are not listed in the cap kit (all the ones pertaining to the hsize pot/opamp). I still cannot adjust the horizontal size though replacing the caps did tighten the image enough for it to not cut off much. Do either of you know the expected voltage of VR2 or the voltage levels for U1? I measured 19V going to VR2 and adjusting the pot I does change the level on the op amp side. The pot ohms out to the full 50k range so the pot is good. Would I maybe need to adjust VR3?
Any idea where to go with this? I'm not very familiar with these CRT boards. I'd imagine that if the Op Amp is bad I would have a messed up display. I haven't pulled the resistors to see if they are good (can't ohm them out in circuit with all the components in parallel). That seems a bit far fetched though because none of them look damaged or burnt.
I just noticed this referencing the schematic, I should have 20-27V on the pot. Seeing as how I only measure 19 could that be a problem?
I'm working on a Tatung Type 38 Monitor in a Megatouch Diamond
According to Merit it uses the same chassis/neck board as the Type 66 so I'm using this schematic: http://www.meritind.com/Service%20Center/Type%2066.jpg
I ohmed out the ground pin on the plug to the chassis and made sure that all the boards are tied to chassis ground (mostly in troubleshooting the touch screen which still isn't working right).
I see no leaking cap, no burnt components, no damage on the board. I work on circuit boards for a living so I am good with rework, just out of practice in troubleshooting and kinda of scared to probe around a 120V PCB.
Not sure what other info that would be helpful to you.
smartbomb2084:
Did you check Q1, Q3, and ZD1?
elderjag:
Did this issue ever get fixed? My Megatouch Maxx Jade is doing the same thing. the screen horizontal is to wide and adjustments and cap kit does not solve the problem.
I have the tatung 66 monitor in my machine
elderjag:
i did see a week or two ago that there are 8 dip switches on the game board. By flipping a switch or two it changes from a 19" monitor signal to a 13" signal. Now i'm just rereading all my merit manuals to see what switch it is. maybe the previous owner switched switches when they started having issues.
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