Author Topic: Pac-Man Monitor Question (Read 2960 times)

korendog · « **on:** November 08, 2005, 12:57:27 am »

I just bought a Pac-Man cabinet and got it home yesterday.

Ken Layton · « **Reply #1 on:** November 08, 2005, 01:56:40 am »

Yes, definitely needs a capkit.

korendog · « **Reply #2 on:** November 09, 2005, 01:43:57 am »

Ken, You are getting a christmas card this year! Thanks for the info. I'll fire that cap kit up and see if that helps. -Jarrett

korendog · « **Reply #3 on:** June 29, 2006, 10:48:58 pm »

Ok, I finally got the cap kit done on this monitor. However, this didn't fix my issue. Please refer to the picture at the top. I failed to install the sync modification which is supposed to prevent the horizontal curl. Is this the syndrome I am experiencing? The main reason I didn't install the modification is because I didn't quite understand the instructions. I was a little confused as to what exactly I was supposed to do. Any help or input would be greatly appreciated. Also, I noticed when starting my cap kit that a cap kit was previously done on the monitor, but I don't think the sync mod was done. I also noticed that the width coil wasn't in the best of shape. ie; broken, but intact. Could this also be causing the issue. I did a search and found a post where a similar issue was caused by someone messing with the B+ adjustment. I know I have a few avenues to check out but I just wanted to get some input first before I continue. Thanks in advance, Jarrett

Kevin Mullins · « **Reply #4 on:** June 29, 2006, 11:47:20 pm »

Have you tried adjusting the sync just to see if it affects this issue?

Ken Layton · « **Reply #5 on:** June 30, 2006, 12:48:23 am »

Monitor in question is a......

?? Make and model please.

korendog · « **Reply #6 on:** June 30, 2006, 08:46:12 pm »

Sorry, this monitor is a Electrohome G07-CBO 19 inch that is in my Pac-Man cabinet. I tried adjusting the sync once I got the monitor capped and back into the cabinet, but no luck. The "bottlenecking" as I refer to it is still there. -Jarrett

Ken Layton · « **Reply #7 on:** July 01, 2006, 12:15:09 am »

I've been sqwuaking to the capkit makers about this for years. Capacitor C517 should be changed from 100 uf to 220 uf at 25 or 35 volts.

Capacitors C517 and C518 are connected in parallel so their actual value becomes 100 + 220 = 320 uf. These caps control the "squareness" of the picture. I've found through my experience over the years to change C517 to 220 uf. So in other words 220 + 220 = 440 uf which makes a more square picture like it should be. All cap kits I buy for the G07 I open them up and replace the 100 uf cap intended for use as C517 with a 220 uf one. This is the easiest and cheapest thing you can do to see if this corrects your picture. If by chance it doesn't then you change these two things next: width coil and flyback.

korendog · « **Reply #8 on:** July 01, 2006, 12:27:42 am »

Ken,
Once again, thanks. Does Radio Shack normally stock that particular capacitor? ie; 220 uf @ 25 or 35 volts Also, on my cap kit it has both 517 & 518 listed as 16V Should I just go ahead and replace them both to get them up to your spec of 25-35 volts? Or wont the voltage matter? This sounds like it will fix my problem. (fingers crossed), but if not what would a width coil and flyback run me?

Ken Layton · « **Reply #9 on:** July 01, 2006, 01:33:32 am »

I've always bumped the voltage rating on C517 and C518 up to at least 25 volts to make them last longer. The original (and replacements) rated at 16 volts just don't last very long.

Yes, the Radio Shack number is:

272-1029 Radial Lead Electrolytic Capacitor, 220 uf @ 35 volts (around a dollar in price).

Let me know how you make out on this problem.

korendog · « **Reply #10 on:** July 03, 2006, 08:02:36 pm »

I ran to Radio Shack today and picked up the two replacement capacitors I needed. I pulled the chassis and I'm ready to complete the cap kit including the sync mod. I did a search and found Bob Roberts notes on doing the sync mod on the G07 which cleared up a bunch of my questions. However, seeing as someone did a cap kit on this monitor before I want to make sure I'm switching the right caps. On Bob's notes it says to totally get rid of the cap in position C501. Then take C303 and put it in C501. Right now the markings on the C303 cap are as follows (PEE 1K 50TSC). Just want to make sure that is correct before I put that one in the C501 position. Finally it says to put a 10-22uf @ 25volt minimum cap in the C303 position. I also took another look at the width coil and it appears to be broken, but still functional. I think whoever was attempting to fix this problem in the past tried to adjust the width coil too far and cracked it at the base. If anyone has any suggestion on where I can pick up a replacement for this chassis I'm all ears. -Jarrett

Kevin Mullins · « **Reply #11 on:** July 03, 2006, 10:51:49 pm »

Is C303 cap an orange or "bubble gum" shaped looking cap ?
(curious for my own sake, don't have a G07 to look at)

Bob Roberts usually has those width coils around.
GO7 Electrohome Width Coil $10.00
http://homearcade.org/BBBB/parts.html

Check to be sure that the ferrite core on your width coil isn't broken. (the adjustable part inside)
Alot of people use a small screwdriver on these and they tend to crack and crumble.

korendog · « **Reply #12 on:** July 04, 2006, 12:57:20 am »

Yes, C303 is an orange "bubble gum" shaped looking cap. I went ahead and did the remaining sync mod and replaced C517 & C518 like Ken instructed me to. It seems like all these things I did helped, but the picture is still not 100%. I'm guessing the final piece to the puzzle might be to replace this width coil. I'll head on over to Bob Roberts and pick one up.

Kevin Mullins · « **Reply #13 on:** July 04, 2006, 10:22:06 am »

What is the issue at the moment?
Is it similar to what you has already?

korendog · « **Reply #14 on:** July 04, 2006, 01:17:24 pm »

Yes. While the cap kit and sync mod fixed most of the "bottlenecking" there still is a slight difference in the screen from left to right if you are standing directly in front of it. For example , during gameplay of Pac-Man the power pellets on the left side of the maze are normal, but the right side power pellets are slightly "squashed" or compacted. If the monitor was in a horizontal position the squashing would be on the top and normal on the bottom. Again, the difference is slight, but still noticable. Any suggestions?

Ken Layton · « **Reply #15 on:** July 04, 2006, 05:41:17 pm »

Adjust the vertical linearity control.

korendog · « **Reply #16 on:** July 05, 2006, 07:16:31 pm »

Ken,
I'll give that a go and see if it helps. I also emailed Bob Roberts today and placed an order for a new width coil.

saskvidkid · « **Reply #17 on:** July 12, 2006, 08:22:04 pm »

I have the same problem with 2 of my ms pacs at the moment and I have done cap kits on them both as well have changed the width coils and still have the problem any suggestions would be appreciated. Cheers

korendog · « **Reply #18 on:** July 12, 2006, 10:04:01 pm »

I adjusted the vertical linearity control as Ken suggested and this cleaned up most of it. After I installed a new width coil I adjusted that also. Both of these together took care of almost all of the problem. However, I still have a slight downward bend on the right maze tunnel which is in the center of the monitor. All in all the monitor looks 95% which isn't bad. I guess I can live with it.

Ken Layton · « **Reply #19 on:** July 12, 2006, 11:52:56 pm »

Now tweak the "H Freq" control just a tad bit to finally eliminate the curl/bend.

korendog · « **Reply #20 on:** July 13, 2006, 03:45:14 pm »

Ken,
Thank you yet again.

That last little nugget cleaned it up and now the picture looks perfect. It is amazing how great the gameplay looks when you get the monitor adjusted right. Hopefully this post will help others with similar problems on an Electrohome G07-CBO monitor.


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