Final Fight K7000 Monitor Problem

[KevinMullins]

Ok, so the pinout I described was correct then.
1. Input
2. Base
3. Common (ground)
4. Ouput

(the STR30123 is different)

The output on that VR should be about 123VDC, hence the part number.
The input voltage I'm not positive on, I don't have a 19" chassis to verify with.

Check that the insulator for the H.O.T. is good and that the HOT is not shorting to ground. (i.e. not touching the heatsink)

You could pull one leg of D10 to prevent shutdown, but your B+ is just too high anyways to begin with.

 

[syplex]

HOT is not shorted to ground, mica insulator looks good. VR should be outputting B+ of +123V but it is +160V. I currently have one leg of D10 pulled. I've only been turning it on for a few seconds to check voltages.

K7000 service manual has IC4 (VR) typical voltages:

Pin 1: +163.5V
Pin 2: +125.2V
Pin 3: Ground
Pin 4: +123V

My voltages:

Pin 1: +165V
Pin 2: +143V
Pin 3: Ground
Pin 4: +160V

Anyone know the yoke impedances for this monitor (19k7901)?

 

[syplex]

Ok I finally got my B+ fixed! I'll tell you how but first here's what I did.

I checked R84, R85, R86, R102, and C56. All tested good.

I replaced R84, R85, and R86 anyways.

One other thing I found was that R83 was missing. It looked like it was there but the legs were cut off. I put in a new 680 ohm 1/2 resistor.

I then replaced my VR with another one even though it tested good thinking it could have been bad somehow.

None of these things changed anything, the B+ voltage was still high.

So then I started testing tons of traces. I found that Q11's collector (middle pin) was not always making contact since its pad had been destroyed. I laid down some silver conducting trace and then also soldered in an extra component leg on top of the short trace to make sure it was always connected. After that I replaced IC2 with a new one. I also removed and cleaned the pads then re-soldered the rest of the large resistors I hadn't done this to yet.

After these changes my VR is outputting +123V. I get neck glow and I can see something on the screen if I turn up the brightness, but I get no game graphics at all.

 

[Peale]

R83 was probably removed at the factory. They'd do that all the time - add components @ assembly, but remove them by cutting them out for revisions.

 

[syplex]

Ok so today I decided to swap in my newly acquired Raiden II board to see if it worked in this cab. I actually was having a problem with it making a loud buzzing sound in my Ms Pac cabinet with a lizardlick jamma to pac adapter (the one with the integrated power regulator) so I thought I'd put it in my final fight cab that has working sound but no video.. then if I heard buzzing I would know it was probably a problem with the Raiden II board.

Well guess what, the monitor works and displayed the game! I tweaked the focus on the new flyback and the rest of the pots to get a good picture and played a quick game and lost since it is sideways hehe. Cleaned the contacts on FF and plugged it back in, still no picture.

So I guess now I will be trying to figure out how to diagnose the video output circuit on final fight. Any suggestions?

 

[mecha]

not sure if this has been tried already, but Final Fight being a CPS boardset is comprised of multiple interlocked boards, and I think a common problem with the CPS1 has to deal with the boards needing to be reseated.

like I always mention, I have no first-hand experience with CPS1, just CPS2.

could very well be a miscommunication between the rom and main boards. if I recall, Final Fight will only flash the rom check very briefly and then it disappears, during which your monitor just might not be warmed up all the way.

though it's good you can rule out the monitor now at least!

 

[syplex]

Update for anyone following, the lizardlick Ms Pac adapter can only supply 3A on +5 and the Raiden board needs 5A so thats what was causing the buzzing in the ms pac cabinet.

I am looking for another CPS1 'A' board to swap my final fight game board onto, I suspect the video driver is dead. I tried re-seating the FF 'B' board several times to no avail. If anyone has a working A board they want to get rid of, send me a PM!

 

[syplex]

Bad news. I got a new CPS A board and swapped the final fight board over and everything was working great! Final fight was playing well and my buddy and I played it for about 20-30 minutes but then....

The monitor display collapsed into a vertical bar an inch or two wide and shortly thereafter the main cabinet fuse blew. The main heatsink was extremely hot. The HOT was shorted. I figured it was because it overheated, maybe I didn't put a good amount of thermal paste on it, so I replaced it and made sure the new one was well coated. I checked lots of HV components and they all test good, VR tests good.

Now its blowing fuses (main cabinet) INSTANTLY. I disabled the shutdown circuit by pulling one leg of D10 and it still blows fuses instantly. HOT and VR test ok. What should I look for? What do you think went bad to cause the display to shrink to a vertical bar? That to me sounded like the HOT dieing but then something else died that is causing it to blow fuses instantly.

 

[syplex]

Anyone? Nothing tests bad so far. My plan is to replace C57 (even though its new from the cap kit and doesn't test shorted) since I read that instant shutdown can be caused by bad C57.

Suggestions?

 

[KevinMullins]

Check your rectifier diodes. (four matched diodes in the power supply section)

 

[syplex]

They all test good, a little under 0.500 with diode test in circuit. Any other suggestions?

 

[Peale]

You have to test them OUT of circuit. Test them first one way, then the other. Testing them in circuit, you're going to test the ones beside them as well as the one you're testing directly. You don't have to remove them, just unsolder a leg and pop it out of the hole.

 

[syplex]

They test good out of circuit as well. Also D23 and D24 test fine out of circuit. Also re-tested C62, R103, D16, D17, C36, C37, C38, C35, R74, R89, R97....

What should the impedance be on the AC input to the board? What about from the other side of the rectifier?

 

[Peale]

Wow...this thread is getting epic. Okay...next post, detail where you sit right now. Blowing fuses? B+ voltage?

 

[syplex]

Ok this is where it currently stands (or sits).

Currently blowing fuses (main cabinet AGC 3amp fast blow fuse) instantly. Can't test B+ voltage because of that. Cab fuse doesn't blow if video board not installed. I have HV shutdown disabled via D10 leg pulled. I'm running it with only the video board and main switching power supply connected to the cab (no game pcb), and without the degaussing coil (P3) connected. I'm trying to limit variables.

A fair amount of components have been replaced on the board, before this current problem:

Q11 (Replaced with NTE2302)
IC4
IC2
C36
C37
C38
D18 (Replaced with NTE558)
C205 (on neck board)
R101
R84
R85
R86
Flyback
Cap Kit (C10, C11, C12, C13, C18, C20, C21, C22, C23, C40, C42, C45, C46, C48, C50, C56, C57)

Also the following has been done. I believe these are related to the forced blanking circuit:

R83 added (had clipped leads)
A short from R18 to ground was removed (on underside of PCB)

 

[Peale]

By video board do you mean the chassis, or the Final Fight board?

 

[syplex]

Video board = WG K7000 (19K7901) pcb.

When I hear chassis I always think of the metal monitor frame that the k7000 board mounts to so I never say it.

 

[Peale]

Do you know about lamp fuses? Take a standard incandescent bulb and solder wires to it, then solder those wires to a blown fuse. You'll have to use sandpaper to remove the plating on the fuse, and probably have to loop the wire around the base instead of soldering directly to it. That'll help you save on fuses. If it comes on BRIGHT, there's a short.

Even though that list of stuff you've replaced is pretty long, test the caps C36, C37, C38, C69 again. It's possible one of them has shorted due to other parts going bad.

Retest the HOT. Swap it if you can - sometimes they can go bad but read good.

Finally, the flyback - they can be bad out of the box (but it doesn't happen often). Ken Layton recently had this happen to him.

 

[syplex]

I am aware of lamp fuses, but I haven't made one yet. I will make one now though since I am going through fuses like water.

I have already re-tested C36, C37, and C38. I have only tested C36 out of circuit, so I'll re-test C37 and C38 out of circuit. C69? The caps don't go up that high, did you mean R69 or something else?

The HOT died when the fuse most recently started blowing. I replaced it and got the same thing, then I re-tested it and swapped it with a brand new one. Same thing. I have re-tested IC4, but I haven't swapped it with another one yet. It would be strange if the flyback was bad because it was playing for quite awhile with that flyback in there. It was when I played it for 30 mins straight that the video board died on me. I thought if a flyback was bad you got no video/hv at all. Is there a way to test the flyback? Can I do it in circuit?

 

[Peale]

The only reliable way to test a flyback is with a flyback tester. One of those things I've been meaning to pick up one of these days.

No, I meant C69. Some K7000s have them, some don't.

You can test all those caps I mentioned in circuit.

Your critical safety cap had four legs, right? Did you remember to bridge them over to the adjacent holes?