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Arcade Collecting => Merit/JVL Touchscreen => Topic started by: OldSkoolGamer on August 11, 2013, 04:56:29 pm

Title: Horizontal size is too large and won't allow me to change
Post by: OldSkoolGamer on August 11, 2013, 04:56:29 pm
Hi everyone :)

I've got a 2nd Megatouch from a friend and found that the horizontal size is too wide and it wont allow me to change it using the pot. What would a fella do in a situation like that? Just replace the little monitor control board with all the pots on it?
Title: Re: Horizontal size is too large and won't allow me to change
Post by: smartbomb2084 on August 12, 2013, 08:23:55 am
Probably bad Capacitors or transisitor controlling the circuit.. it could be a bad pot or broken wire going to or from it.

What kind of monitor is it?     

What kind of Megatouch is it?

DETAILS... DETAILS... DETAILS...   If you want help we need DETAILS.. 

My mind reading skills are a little cloudy today.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: OldSkoolGamer on August 12, 2013, 03:43:04 pm
Unsure of the monitor type...will check when I get home from work today :) but know its a sapphire maxx edition megatouch
Title: Re: Horizontal size is too large and won't allow me to change
Post by: lilshawn on August 12, 2013, 06:37:04 pm
Unsure of the monitor type...will check when I get home from work today :) but know its a sapphire maxx edition megatouch

it should say on the tube or chassis "type 51" (or some other number)

likely you will need to re-cap the chassis. It's probably 20 years old now. it's going to be overdue.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: smartbomb2084 on August 12, 2013, 08:37:33 pm
My money is on a TATUNG TYPE 66 monitor...
Title: Re: Horizontal size is too large and won't allow me to change
Post by: Ken Layton on September 26, 2013, 11:51:10 am
Regardless of which make/model monitor that is presently installed, it will need to be recapped to correct your problem. You will first have to determine the exact make & model so you can order the correct capacitor kit.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: shiori1425 on March 12, 2014, 09:52:41 am
Regardless of which make/model monitor that is presently installed, it will need to be recapped to correct your problem. You will first have to determine the exact make & model so you can order the correct capacitor kit.

Hey Ken, or anyone else who knows,

I'm having the same issue as the OP. I'll look into getting a capkit to fix the horizontal size issue it's having.   

My question is would this cause the touchscreen to be off on the horizontal as well? I just bought a Maxx Diamond a few days ago (my first Megatouch) and it's horizontal size is to large and the touch horizontal is off when you are not in the center.  The touch gets worse as you move further away from the center of the screen but only in the horizontal. Could these be related of do I need to look into a new touch screen/touch controller?


Thanks
Title: Re: Horizontal size is too large and won't allow me to change
Post by: lilshawn on March 12, 2014, 08:04:11 pm
yes. the overlay is calibrated to a nice square screen. with the width all stretched out, the system displays the correct video but the monitor does not.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: shiori1425 on March 13, 2014, 11:17:40 am
yes. the overlay is calibrated to a nice square screen. with the width all stretched out, the system displays the correct video but the monitor does not.

Thanks for the reply.  I've been messing with it and haven't made and headway.  I have a cap kit being delivered today and I've already tried a different controller.  I'm really hoping that the cap kit fixed the monitor adjustments and that the adjustments working will fix the touch screen.  I do not want to have to replace the touch screen.  :banghead:

Title: Re: Horizontal size is too large and won't allow me to change
Post by: lilshawn on March 13, 2014, 11:52:28 am
the overlays are pretty tough. if the overlay is faulty, you'd likely have touches picking up along the very edge. the fact you get touches all over the screen...but they are just off, shows it's working.

most times if it's faulty it's just broken wires causing it. sometimes you can repair the wiring if it's faulty, but if a transducer has been damaged due to impact or other damage, you won't be able to fix it and you'd have to replace the overlay.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: Ken Layton on March 13, 2014, 12:53:11 pm
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.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: shiori1425 on March 15, 2014, 10:44:54 am
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 (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.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: smartbomb2084 on March 24, 2014, 08:34:47 am
Did you check Q1, Q3, and ZD1?
Title: Re: Horizontal size is too large and won't allow me to change
Post by: elderjag on August 14, 2020, 02:56:20 pm
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
Title: Re: Horizontal size is too large and won't allow me to change
Post by: elderjag on August 18, 2020, 03:17:28 pm
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.
Title: Re: Horizontal size is too large and won't allow me to change
Post by: smartbomb2084 on August 19, 2020, 01:10:49 pm
It is likely capacitor C19 is your problem.  It is a 4.7uf/50Volt  BI-POLAR Capacitor.

I have changed a few of these over the years for this very symptom in Type-66 Monitors.

I seem to remember that the last time I changed one, a replacement was hard to find and I don't know where to get one now.

Maybe Ken can chime in with a source for it?

Good Luck....