WG9800 with a Horizontal size – pincushion problem

[poopface]

I have a WG9800 with a Horizontal size – pincushion problem.  I have attached a photo of the monitor running the Nokia geometry test at 800 x 600 @ 60 Hz.  All of the controls on the OSD appear to be working except the horizontal size and pincushion, which have very little effect on the picture.  I do have the schematics and a digital multimeter; however my knowledge of electronics at a component level can be described as intermediate at best so please bear with me.  I have however been able to repair many of my own arcade and pinball machines by lurking on the forums and newsgroups and learning from others trouble shooting and repair experiences.  I have been unable to resolve this on my own so far so I thought it was about time that I request assistance from the forum members that are obviously very experienced in these types of repair.  Thanks in advance.

[grantspain]

i would try recall first,then maybe factory settings
difficult to see if this is a component fault in the horizontal size circuit or corrupt eeprom

[poopface]

Thank you for the response.  I am not that familiar with the monitor repair terminology, so I just did the best that I could.  Let me know if this is what you wanted me to try.  First I recalled the factory settings via the OSD which caused no changes.   Then I adjusted VR201 H-Size on the monitor chassis, which also caused no changes.  I then changed the resolution to 640 X 480 @ 60Hz and repeated the whole process with no changes to the screen whatsoever.  If this is not what you wanted me to do please advise.  I see from the schematic that the 24LCOB eeprom located at IC702 is socketed.  Should I try to replace that with a new blank one?  What would you like me the do next.  Try to spell things out for me if you would, because I am an extreme novice when it comes to the terminology involved.  If you would like some photos or videos of me performing certain tasks on the monitor to help you troubleshoot, just let me know.  Thanks

[grantspain]

i think this beyond your skills to repair,sounds like either the horizontal size circuit or the pincushion circuit has a component in fault

[poopface]

Thanks once again for the reply.  I will agree that this repair is beyond my skill level to complete by myself at this time, after all that is why I am on this forum to seek assistance in troubleshooting and repairing this monitor with the help of someone who does have the experience, knowledge and skill to do so.  I have successfully repaired many, many electronic devices in my lifetime before I got into the vintage arcade hobby. My first computer was a Sinclair ZX81 based on the Z80 8-bit processor that came in a kit that you had to assemble and was given to me on my 16th birthday, since that time I have enjoyed any hobbies that are electronics and or computer orientated.   I have 3 stand-up games a sit down driving game a megatouch a slot machine and 2 pinball machines; I have also had and sold 2 more stand ups, a pinball, and driving and megatouch machine.  I have already completed one mame cabinet and am on my second new and improved version (you know how it is) The only thing that worked when I bought it and has not required any repairs is the slot machine.  I am very comfortable with removing the monitor from the cabinet and safely discharging it. This is actually the fourth monitor that I am trying to repair.  I have already repaired two LCD’s and one CRT.  I am comfortable with taking various measurements on PCB test points, traces and components in and out of circuit as necessary, whether it is for voltage, capacitance, resistance or whatever else that can be performed with the equipment that I own.  I have above average soldering skills and have absolutely no problem removing and replacing as many components as necessary.  I have no problems following troubleshooting directions as long as I understand the terminology, especially if it is presented in a flow chart format with detailed directions.  I want to learn and have the satisfaction of physically doing it myself even if I do require the guidance and assistance of someone else.  This is my hobby, you can’t pay someone to do your hobby for you, and if you do then it is not a hobby anymore.  Any help from anyone will be greatly appreciated.   

[grantspain]

if i could find a schematic for it then i could help some more

as you have no horizontal size control i would say thats the circuit to start looking at,on older chassis that would be controlled by a transistor-not so sure on later digital chassis

[poopface]

Thank you so much for your help.  Wells Gardner provides no information whatsoever about this monitor on their website.  The closest thing to it is the D9400 which I also own and although they may be similar in operation and specifications the board layout appears to be much different.  Here are some schematics that I found that are supposed to be for the D9800 series.  I have also attached the D9400 series schematic for comparison.

[grantspain]

it shows a horizontal size pot at vr202 on the schem

[rocomat]

Hi!

I have the same problem with same monitor,  a WG D9800 (D9810), hor size and pincussion adjustment does not work.
My picture looks like the one above, with extreme bowing.

poopface: you got a solution? 

grant: you mean vr201? see http://www.wellsgardner.com/pdf/Board/D9400.pdf