Semi-working k4600 dead after cap kit

[hindered]

Anybody have any ideas? Did you take a look at the pics I posted for anything weird?

 

[hindered]

Okay, more information, sorry about the crappy pics.

1: What is this white cylinder? It's marked 1 2 3 4. One of the pins had no continuity to the next component on the trace due to crappy solder/pcb damage. This component looks like it's fed pretty directly from the AC in, so it would explain why no power is getting to the rest of the board, right?

2: Another picture of the weird modification to the degaussing circuit. This is mounted to the metal around the tube and does not detatch. I ended up cutting this circuit out of the loop entirely and have the degaussing coil running straight to the board now.

3: A picture of the yoke. These wires are NOT detatchable without cutting.

4: A picture of the modifications on the solder side of the main chassis. The red wires were there when I acquired the monitor.

In addition to the stuff above, I went around and did general board cleanup -- did a bunch of continuity checks, touched up some solder joints, bridged some shady traces. I also found a cap that I forgot to clip the leads from, COMPLETE bonehead move. I don't THINK they were making contact with anything else, but who knows. I'm thinking that the leads + #1 from above would quite possibly explain why I wasn't getting B+.

So, before I put this beast of a monitor back together, is there anything else I can check? Anything else I can do? Is there any testing I can do with it apart, or do I need to put it back together 100% before trying?

 

[hindered]

Of course I forgot to attach pics....

 

[modessitt]

1: What is this white cylinder? It's marked 1 2 3 4. One of the pins had no continuity to the next component on the trace due to crappy solder/pcb damage. This component looks like it's fed pretty directly from the AC in, so it would explain why no power is getting to the rest of the board, right?

I have no idea. can't tell from your pic, nor where it was attached.

2: Another picture of the weird modification to the degaussing circuit. This is mounted to the metal around the tube and does not detatch. I ended up cutting this circuit out of the loop entirely and have the degaussing coil running straight to the board now.

That is the normal way a K4600 degauss circuit is wired. I'm not sure for the exact reason it is there, but it should be.

3: A picture of the yoke. These wires are NOT detatchable without cutting.

Normally they just unplug from the yoke. Pull on the red wire at the top of the yoke and see if it unplugs. the yoke is labeled R,Y,G,B to show where the colored wires plug in. Sometimes the R & B or G & Y positions are switched in order to flip the picture. I've seen people solder these directly when the connectors get loose and won't stay on.

4: A picture of the modifications on the solder side of the main chassis. The red wires were there when I acquired the monitor.

So - leave them alone...

 

[hindered]

I have no idea. can't tell from your pic, nor where it was attached.

It's right by where the AC comes in, next to the fuse.

That is the normal way a K4600 degauss circuit is wired. I'm not sure for the exact reason it is there, but it should be.

Thanks for answering this, although I've asked about it before. Wish I would've been told this before now, now I need to re-incorporate it. Shouldn't be too hard.

Normally they just unplug from the yoke. Pull on the red wire at the top of the yoke and see if it unplugs. the yoke is labeled R,Y,G,B to show where the colored wires plug in. Sometimes the R & B or G & Y positions are switched in order to flip the picture. I've seen people solder these directly when the connectors get loose and won't stay on.

Yeah, I do believe these would pull off. They appear to have been swapped, I'll go ahead and put them back on the right way.

So - leave them alone...

That's the plan, but I've been asking all along: are they 'normal' or if they are indicative of repair work? That's still the question.

I still feel pretty stupid about the non-clipped leads. I've had a relatively high success rate with monitor repair and must have gotten overconfident. Guess I need to realize I'm still new at this and need to take my time and ask more questions.

Tonight I'll repair the degauss circuit and button everything back up. Thanks for the feedback.

P.S. I still maintain that 20ezs are a lot easier to work on than this beast. I guess if you needed to do something to one of the daughter cards that would be a piece of cake.. but everything else.. man.

 

[modessitt]

That's the plan, but I've been asking all along: are they 'normal' or if they are indicative of repair work? That's still the question.

Sometime they are undocumented repairs done at the factory, and sometimes they are done by a tech who is having problems with a signal making it around the board. Either way, leave them there...

 

[hindered]

Semi-success -- have power to the monitor again. I'm pretty sure the white cylinder was the culprit. B+ is at 132, is this too high? Is it adjustable? Picture will sync (no rolling V or H) but isn't displaying properly... it almost looks like the H hold needs tweaking but that just makes the screen start rolling -- I have negative composite sync coming from the JAMMA board to pin 3 of the connector as Fromm's flowchart says.

 

[modessitt]

You're attempting to adjust it with L351?

 

[hindered]

Adjust what, the B+? I haven't attempted to adjust that. Does it need adjusting? Is it the pot on the little daughter board on the far left of the board?

 

[modessitt]

Adjust what, the B+? I haven't attempted to adjust that. Does it need adjusting? Is it the pot on the little daughter board on the far left of the board?

The pot on the left daughtercard is for adjusting the screen control (brightness). Some will have two pots, and the 2nd is for the horizontal positioning.

No, I was referring to adjusting the horizontal hold pot on the right daughtercard to get your image better. It is in the center of the board, and usually missed:

http://therealbobroberts.net/slanted.html

 

[hindered]

The pot on the left daughtercard is for adjusting the screen control (brightness). Some will have two pots, and the 2nd is for the horizontal positioning.

No, I was referring to adjusting the horizontal hold pot on the right daughtercard to get your image better. It is in the center of the board, and usually missed:

http://therealbobroberts.net/slanted.html

I was talking about the pot on the very very far left (by the bottlecap transistor) on the board that's mounted to the frame. I'd guess that's a b+ adjustment pot but I didn't fiddle with it.

I'll take a look at the right daughtercard when I get home today to see if I can find the pot to adjust -- thanks for the link. Reading it now.

EDIT: Excellent link, thanks.

 

[hindered]

Ok, I got the sync dialed in. I didn't have anything that could reach it so I had to pop out the card, make an adjustment, and pop it back in. Sucked, but it only took me 4 tries.

Now the last problem.. the colors all seem really saturated. I have a test pattern that starts out BRIGHT, less bright, less bright, and then black. On this monitor, it's BRIGHT, BRIGHT, BRIGHT, black. I've fiddled with the r/g/b drive and the cutoffs, and the black level and the brightness... nothing seems to solve the situation. On the control test screen, the image is supposed to toggle grey/white for the control pressed, but the control always appears white... similar to the test pattern colors being overdriven, the grey is overdriven.

Any ideas?

 

[modessitt]

Not without a pic, no. Have you tried a regular game board?

 

[hindered]

Two pics, the 4600 and the same board on a 4900. Ignore the 'discoloration' on the 4900 pic, the color is fine in person, it's the camera. I only included it to show that the color is supposed to gradually fade out on the test pattern.

This is a DJ boy board in test mode, though I haven't tried anything in normal gameplay yet, no.