WG 19K7901 She's alive!!!

[Lutus]

I picked up this 4-player Xmen (The Main Event) and the guys says "don't work".



I believe the chassis is a WG 19K7901, which from a little research is basically a K7000.  It is connected to a Philips ECG MV A48ABK05X.

The chassis serial is 85X0216-001E.

Here are some pictures for affirmation, confirmation... etc...







Here is the deal so far.  I powered up the machine and heard the monitor start to whine for about 2 seconds then it shut itself off.  I left the machine on and gave the machine a credit.  The Xmen Jamma board powered up and I could play the machine blind. 

I turned the machine off, discharged the monitor, reseated the anode cap and turned the machine on with the lights off to check for a little lightning.  This is what I saw...



The sweet MSPaint blue lines shown above were actual sparks, kinda looked like a spider web.  This was on the OUTSIDE of the tube by the way.

I shut down the machine and moved the red anode wire away from the tube neck, turned off the lights and tried to take a video of the sparks.  BUT, 3 times in a row after that it did NOT spark.

It still sounded like it was trying to start up and then go into shutdown.  Looks like the original flyback, and also looks like someone tried to do a cap kit on this at some point. 

Where would you guys suggest I start?

[Lutus]

Attaching pics for larger viewing

[Ken Layton]

You have a k7000 with original flyback.

First:

Take a dry towel and carefully wipe the dust off the back of the tube around the yoke where the 'sparking' was occuring.

Second:

Install a capkit and a new flyback. Your flyback is original and they develop cracks and leak/arc high voltage. Also order a voltage regulator just in case. It's over by the large white ceramic resistor and the part number starts out with STR. Get the EXACT number that's stamped on the part. It'll be either one of these four part numbers: STR30123, STR30130, STR3123, or STR3130. Each are different electrically and mechanically so you must look at the one installed in your monitor to see the correct number. Bob Roberts carries it.

One other thing: moisture can cause the arcing you describe too. So be sure this monitor has been inside your house in a temperature controlled environment for a week before powering up to make sure moisture is gone.

[Lutus]

Thanks Ken, will do all that you have described.  Will be out of town the next couple of days but will update you then.

Take that time as a chance to get rid of humidity as well.

[qrz]

 good idea to discharge the crt before working with the anode ... can eliminate those nasty surprises...

 the anode cup may also have carbon tracks due to the arcs. it will need to be replaced if severely damaged .

can seal cup with a fine bead of silicone rubber or corona dope to reduce arcing . ( common on projo and large crts)

and no,  "corona dope"   is NOT a mexican beer     

qrz

[Lutus]

Cap kit on the way from Bob Roberts as well as a flyback transformer and a STR3123.  After removing the chassis I see that one of the large capacitors had "oozed" all of its insides to the outsides.  That is a good indication that the cap kit can only help! 

Will update after the cap kit is installed.

[SirPeale]

Is the ooze white?  If it is, it's glue, not cap innards.

[Lutus]

No, its all blackish brown.  Some of the caps I am able to wiggle and one or more of the legs is about to break off.  The usual old cap scenario.

[Lutus]

Got my cap kit in from Bob Roberts.

I replaced all the caps, the flyback transformer, and the STR3123.

Now, all was well until I turned on the cabinet.  The 4A, 32V fuse blew on powerup.

I replaced the fuse with a 4A, 125V fuse that I had from another machine that is down and measured the input voltage to the monitor before I plugged it back in.  It read 118V or so.  I then plugged the monitor back in and the fuse blew on powerup again.

So....... yeah.

[Ken Layton]

A 4 amp fuse!? That monitor should have a 1― amp slo-blo fuse (250 volt) in there.

Was the STR3123 the original number on the regulator in there originally? When you replaced it, did you remember to put the mica insulator back and reapply fresh silicone heat sink grease to it?

This monitor requires an isolation transformer for power. Never connect it directly to a wall outlet or extension cord.

[Lutus]

The fuse is question is NOT the one on the monitor chassis, but one near the power input/isolation transformer in the bottom of the cab.

The cab has two fuses on the input lines (5 and 12 volt I believe) going into the PCB.  These are fine.

There are 2 other fuses.  These are the two in question.  The one that blew and was replaced was NOT the one that blew the second time, it was the other fuse of the two.

On bob roberts website of setting up the AC wiring for jamma he only has 1 fuse.

This cab has been rigged, power switch bypassed so the cab turned on via circuit breaker.  In order to turn power on to the cab now, I have to depress the "backdoor safety switch".

I am thinking about redoing ALL the wiring in the machine at this point since it looks like kind of a kludge job anyways.

[sarge]

About the only things that can cause a line fuse to blow, outside of incorrect wiring, are the monitor and/or marquee fixture.  Both of these you can unplug and power on machine to see which, if either, blow the fuse when plugged in.

[Lutus]

I was just about to go unplug the monitor fixture and see if that was the dealio.  Will update shortly.

[Lutus]

Well I got some 3 amp slo-blo fuses from rat shack and replaced both those fuses (blown one and the 4A one) and I unplugged the monitor fixture.

I took a look at the STR3123 and sure enough the insulator was slightly twisted so that the back of the STR3123 was touching the chassis.

I reseated the insulator, check for continuity between the STR3123 and chassis wth a meter and didn't have a short.

Plugged in the monitor and I hear it warming up.  No explosions or anything.  But still no neck glow.  Is the STR3123 still good after it is shorted to ground like that?

[Lutus]

Correction, it was NOT the STR3123 that had the mica insulator shifted out from behind, it was the 3 legged IC that is mounted right near the flyback where you have to bend the center prong back a little bit to mount it.

That is the IC that the back of the chip was shorted to ground.

Looked at it and it was the HOT that I replaced that was in my kit.  I put the original HOT back in and it sill doesn't have neck glow.

[sarge]

Is the fuse in your monitor good?  Are you sure that the HOT you put in is good?  Also check C36 to see if it is shorted. 

[Lutus]

The fuse is good.  Well I replaced the original HOT which I think was bad to begin with and when I replaced it the insulator shifted when I screwed in the mounting screw so the HOT shorted to chassis. 

The question is, is my replacement HOT shot now that it shorted to chassis ground?  Or will it still function after that.

C36 is not shorted.

[Lutus]

Is a normal NPN transistor test enough to determine if the HOT is workable or not?

[grantspain]

just go on ohms and read from collector to emitter/base,if you get dead short on one or both then its knackered

[Lutus]

Alrighty peeps... the HOT is OK.  I do not have a short on either AND my readings are very similar to :

2SD1398              (these figures are from Menace in the "Monitor FAQ" topic)
1 to 2 open
1 to 3 53
2 to 1 477
2 to 3 511
3 to 1 53
3 to 2 open


So, now, I need to start reading voltage with the puppy turned on.

Where can I measure B+ easiest?

What should the voltage be on each side of the large white resistor R301?

[Lutus]

I measured either side of R301 (white resistor mounted on side) and one side showed no voltage and the other showed around 24 then cut off to 0.

Also measured the vertically mounted R103 and it shows around 24 volts then shuts down also.

Let the speculation begin.  I haven't had much more time for measurement but the fuse doesn't blow. 

On a side note,  the "lin coil" kind of looks like it has oozed out like the other capacitors.  It has the "black goo" around a little bit of the bottom.  Anyone seen that before?

[Lutus]

D19-D22 are OK (not shorted).
C59 and C64 are OK (not shorted).
R103 not open.  Measures correct.

As soon as power is applied the voltage starts to go up on R301 but then the thing goes into shutdown mode.

The fuse is NOT blown.

What causes shutdown but doesn't blow the fuse?

[halfmachine]

R103 not open.  Measures correct.

As soon as power is applied the voltage starts to go up on R301 but then the thing goes into shutdown mode.

The fuse is NOT blown.

Are you measuring one side of R301 with respect to ground or are you measuring both sides of R301? Measure voltage (using red meter lead) on the side of R301 that's connected to the + pin of C57 with the black meter lead connected to ground. What's the voltage?

I would say you might have a bad cap but since you just recapped it this is probably not the problem. Have you tested your F1 fuse with your meter? And do you definitely hear the oscillating frequency start up and then shut down, like after a second?

Kevin
~Halfmachine~

[Lutus]

Monitor is alive sort of.

I removed D10 (shutdown diode) and the monitor came to life.

I am also reading +172V on both sides of R301.

According to the ol flochart.  My IC4 needs to be replaced.

I must have hosed it when I shorted my HOT accidentely.

Will be ordering one of these puppies then.  Anything I should order while I am at it?


EDIT:  The reason my readings weren't right, I borrowed this meter, all the markings on the front were smeared and I had the thing on AC voltage instead of DC.   DOH! 

[Lutus]

I got in my new HOT and STR3123.

Made sure didn't have any shorts this time and replaced the D10 shutdown diode.

Here is where we are at...

[jrsmith]

HELP!  I have a Wells Gardner 19k7901, can anyone tell me what the rectangular white box is on the neck of the monitor?  I have a Street Fighter II arcade and the monitor comes on but it's white with sideways lines.  I think I am missing this rectangular piece.  Any assistance would be greatly appreciate.

Thanks,
Jeff Smith

[grantspain]

HELP!  I have a Wells Gardner 19k7901, can anyone tell me what the rectangular white box is on the neck of the monitor?  I have a Street Fighter II arcade and the monitor comes on but it's white with sideways lines.  I think I am missing this rectangular piece.  Any assistance would be greatly appreciate.

Thanks,
Jeff Smith

donīt worry about that as you probably have a different yoke,now your problem is either the screen volts is far too high(thats the adjustment on the flyback transformer) or your power supply is not working in the cab--do you get game sounds?

[jrsmith]

No, I don't get any game sound.   How do you adjust that setting on the flyback?  Sorry I know nothing about arcades.  Also, the reason I was asking about the retangle thing on the yoke it it has 3 prongs that it looks like something goes on it.

[grantspain]

forget about the rectangle thing,its not the problem.
your problem is the power supply that runs the game board,you need to check the input voltage and all the output voltages using a multimeter
in the mean time post a photo of the rectangle thingy so we can just double check nothing is disconnected

[jrsmith]

I will try and get a picture out tonight.

Thanks for your help.

Jeff