Avoiding a terminal error fixing a 4600

TK_Monkey

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Of course with the sense of humor these things have when I fired up my Millipede w/ the Braze kit installed to show it to a friend who was in town for the holiday I have monitor problems. Pictures attached, the screen is mostly static with the occasional jump, horizontal and vertical hold adjustment don't remedy the issue. I went to double check and it looks like I've got a vertical chassis 4600 in this machine and after some digging it seems like reflowing the solder on the pins of the daughter cards is a good path to clearing up a lot of issues on these. The solder on the pins of the connectors look okay, but there's next to no solder on one of the legs of the v hold pot so I want to pull both cards and play solder doctor to see if it will correct the issue.

The avoiding a terminal error comes in the process behind that. I know if I'm needing to disconnect everything to pull the whole chassis I need to discharge the tube to avoid getting a buttload of voltage through me, my question is can I disconnect the connectors going to the daughter card and pull those cards w/o having to discharge the tube or will doing that eat me or the components? I've never had to do work on a monitor before so I figure best to double check before doing things, though it seems like I wouldn't have an issue doing that.

FWIW the game plays just fine and I can see the pixels moving when I start up a game.
 

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Although there are numerous things that "should" be done to those if it hasn't already been done, caps, solder joints, etc....... it looks like the sync is out of wack.

Have you tried adjusting L351 ? (little square tin can looking coil)
You have to reach in through a little hole from the side with a small flat bladed screwdriver to adjust.
 

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my question is can I disconnect the connectors going to the daughter card and pull those cards w/o having to discharge the tube or will doing that eat me or the components? I've never had to do work on a monitor before so I figure best to double check before doing things, though it seems like I wouldn't have an issue doing that.

I've pulled those cards without discharging the monitor with no issues. That being said, it takes just a few seconds to discharge the monitor so be on the safe side and do it.
 
Although there are numerous things that "should" be done to those if it hasn't already been done, caps, solder joints, etc....... it looks like the sync is out of wack.

Have you tried adjusting L351 ? (little square tin can looking coil)
You have to reach in through a little hole from the side with a small flat bladed screwdriver to adjust.

That one I haven't tried adjusting. I think I read about that one after I had another person here to help me. I'll give that a shot before I start pulling anything and see if it helps, thanks for the heads up.

I've pulled those cards without discharging the monitor with no issues. That being said, it takes just a few seconds to discharge the monitor so be on the safe side and do it.

Yeah I guess now is as good a time as any to build a discharging screwdriver, I've got a lot of time on my hands at the moment. If adjusting L351 doesn't remedy the issue I'll do it before pulling the cards. I don't have a decent discharging tool put together and I've never done a discharge before, so I was thinking it'd take me a bit to triple check everything and make sure I was doing it right. I'm not feeling as rushed to fix it as I was a day ago, so perspective's changed a bit. Better safe than twitching.
 
You do not need to discharge a monitor just to remove those cards. Just make sure the cabinet's power cord is unplugged.

Never plug or unplug these cards while the monitor is powered on or damage to the monitor will result.
 
You do not need to discharge a monitor just to remove those cards. Just make sure the cabinet's power cord is unplugged.

Never plug or unplug these cards while the monitor is powered on or damage to the monitor will result.

Had intended to have the power cord unplugged, thanks for confirming that the monitor doesn't need to be discharged.
 
Well L351 fixed the primary problem, it's back to displaying mostly normally. The top of the image is a little bowed and it's shifted off to the right (didn't see a vertical position adjustment pot in the schematics). I'll post pics a little later, but looks like cap kit may be a good thing. Also a tiny bit of discoloration on the upper right, only really visible in the player 2 score.
 
For what it's worth, here's screenshots of where it is now. You can see some of the distortion/geometry issues with the line at the top of the screen, and the fact that it's a bit too far off to the right. If it's anything other than a cap kit, lemme know, I'll be ordering the cap kit from Bob in the next day or so.
 

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A 4600 is my favorite to have, but my least favorite to work on. When you have it out re-mount the cards, flip over the chassis, clean out and resolder all the pins for the vertical cards. Don't forget the power section off to the edge. Keeping the cards mounted holds the pins in place while you work. Also, while the cards are removed clean out and reflow the headers along the bottoms as well as the .156 on the interface card.
 
A 4600 is my favorite to have, but my least favorite to work on. When you have it out re-mount the cards, flip over the chassis, clean out and resolder all the pins for the vertical cards. Don't forget the power section off to the edge. Keeping the cards mounted holds the pins in place while you work. Also, while the cards are removed clean out and reflow the headers along the bottoms as well as the .156 on the interface card.

Duly noted, thanks for these, I was just planning on reflowing the pins for the headers and the pots but I'll include all that in the to do list as well.
 
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