WG 25K7193 need help

Blades

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Acquired a Street Fighter II Hyper cab with one of these monitors in it.

The Fuse was blown, I replaced it. It gets red hot and blows again. I'm not to familiar with these monitors so where is a good place to start troubleshooting.

When the monitor starts to blow the fuse, there is NO crackling, no hum and NO high pitch whine(as other members had said their monitor was doing when it blew the fuse), there is just nothing, it just slowly builds up(hot fuse) and burns the fuse out.

What do you suggest I look at first. I get 120v out of the ISO.

I got the damn thing out of the cab(very heavy and the cabinet is hard to deal with) I don't see anything obvious looking at the main mon board or neck board. The flyback looks ok(no burn) so not really sure what the next step is. Any help would be appreciated. Thanks!!


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7193

Check the Horizontal output transistor,check mylar caps for shorts,diode by the yoke plug. Maybe someone someone put that monitor in that game and powered it up without a iso so then you should check what i just mentioned but also check the bridge rectifier diodes and the voltage reg.
 
I checked the HOT and it ohms to 1.57. I've checked the R101 (that other links recommended) it checked out ok and I reflowed just to make sure. The fly physically looks good. R98 checks out ok. The Mylar caps check out ok. Replaced fuse, still blows it though..

Now this monitor has been in the cabinet since birth. And as far as I can tell has always ran off of an ISO.

However, obviously it has been serviced since as the Horizontal Coil looks very new. And it looks like there was a MOD done to it (PIC3). Not sure what it does or if this was standard.

What do you think?

DSC00988.jpg


DSC00989.jpg


DSC00992.jpg



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Have you checked the four diodes (bridge rectifier) in the power supply section ?
Have you checked C36 (?) to see if it's shorted ? (critical safety capacitor)
Have you checked the voltage regulator ?
(check all of the above for dead shorts)

The "mods" you see are normal.
And you use diode/continuity test for the H.O.T. not Ohms.

Recommend re-capping it while you have it out.

Flyback could cause a blowing fuse, but the K7000's generally crack and arc before that happens.
 
Have you checked the four diodes (bridge rectifier) in the power supply section ?
Have you checked C36 (?) to see if it's shorted ? (critical safety capacitor)
Have you checked the voltage regulator ?
(check all of the above for dead shorts)

The "mods" you see are normal.
And you use diode/continuity test for the H.O.T. not Ohms.

Recommend re-capping it while you have it out.

Flyback could cause a blowing fuse, but the K7000's generally crack and arc before that happens.


I will check the diodes tomorrow(upper right hand corner of the board(pic 1) right?) as I will un-solder one leg to make sure that they are good(only way really). I will also check c36(looks like two caps in parallel).

And you are correct on the HOT testing, I knew this, I was testing resistors earlier and for some reason tested the HOT that way. (chalk it up to being up till 3 in the morning).

I guess I'm a little burned out. I revived a vector G05 and a Hanatrix 900E and now onto this monitor. I just want the damned thing to work. As this was the monitor I wanted to just work without having to play the "Throw the parts at it game". Oh well. Going to bed and will try some more tomorrow. Thanks for the help so far though.


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Ok, I've had some a chance to play around.

The Four diodes(Bridge Rectifier) checks out ok,

As for the C36, this is a later revision of the board(P538). No green Critical Safty Cap instead it has a blue C36 and a C69 cap right behind it. Probably does the same thing. Both check out ok.

However I did find the C38 and C37 are both shorted.

I am a little unsure of how too check the Power Regulator(still learning). It is a STR 30130. Do I need to unsolder completely to check it or can I still check it attached to the board? Leg to leg? Diode or Continuity check?

The HOT seems to be ok. I get(still attached to board) I get .448 between the 1st and 2nd leg and the same between the 2nd and 3rd leg. Nothing between the 1st and 3rd(however, continuity wise I do get a beep, between the 1st and 3rd BUT no beep between the 2nd and 1st and 2nd and 3rd leg).

In addition to the other questions. COULD the C37 and C38 blown caps be the or part of the blowing fuses problem, or should I just order a whole replacement kit(caps, fly, hot etc..) from Bob? I suppose I could order the whole damn thing and keep the rest as spare parts.

Again, there is no VISUAL gooo or cracks on the Fly.

Thanks for the continued help!

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These are lots of fun. There is one component, I think it was a cap, that if you did not catch that it was bad it kept reblowing a diode. It works best to check all at once before you power up. The 30130 checks weird and not per standard diode check.

K7193 Troubleshooting - Blows Fuse

Check diodes and replace if necessary D15-D22

Q11 (does not test right with standard diode test, must compare readings to known good or replace)

C37, C38 replace caps (maybe C60)




Fuse ok – no picture

C57 cap - replace
IC4 (test by unsoldering one end of Q10, replace IC4 if video works)
 
I forgot I have one that is giving me problems with a dark screen. HV all the way up but not very bright. Not sure whats up with that.
 
These are lots of fun. There is one component, I think it was a cap, that if you did not catch that it was bad it kept reblowing a diode. It works best to check all at once before you power up. The 30130 checks weird and not per standard diode check.

K7193 Troubleshooting - Blows Fuse

Check diodes and replace if necessary D15-D22

Q11 (does not test right with standard diode test, must compare readings to known good or replace)

C37, C38 replace caps (maybe C60)




Fuse ok – no picture

C57 cap - replace
IC4 (test by unsoldering one end of Q10, replace IC4 if video works)


Wow, this must not be a popular monitor due to the high views but low response. However, any response is better than none. :)

It looks as if D14 and D15 are bad also. But D19-D22 are just fine.

So looks like I'm ordering a whole kit(caps, fly, hot reg etc...) It's cheap enough, might as well.

My next question is What Caps come with Bob's kit on this monitor? I've ordered his kits before but they didn't come with all the caps(bigger) that I needed. Do the C38 and C37 come with his kit? Or do I order those separate?

And even if the C36 and C69 check out ok, should I just replace them anyway?


Thanks for the responses!


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Mods

By the way, your pic 3 (which shows the mods), I think this is from the factory. I have a board with the same mods. Must have been an 'improvement' after the boards were made.....
 
have you installed a capacitor kit on this unit?

check R103
check D18

i'd install a new flyback, HOT and VR.

install new 560uf 200v
 
have you installed a capacitor kit on this unit?

check R103
check D18

i'd install a new flyback, HOT and VR.

install new 560uf 200v


D18 checks fine. But R103 shows about 3.3(instead of the 2.7) which is out of the 5% tolerance so I will replace that. Thanks for bringing that up.

Do you know if any of the Mylar caps (C38,37,36) are included in Bob's cap kit? Or do I need to order those individually?


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Do you know if any of the Mylar caps (C38,37,36) are included in Bob's cap kit?

No ...... electrolytics only.

They should only need changed if open or shorted.

You should check the voltage regulator for shorts. (IC4)
Pin 3 is ground, anything shorted between it and the other three pins is not good.
If you find a short, pull it and check again. If no short found on the pulled IC then check on the solder pads. If short found on the pads then you still have something else shorted.

Wow, this must not be a popular monitor due to the high views but low response.

Quite popular in my opinion.
Durable, easy to repair, parts readily available, etc, etc.
 
In your very first pic - you see in the dead center some resistors where the board is baked brown. Thats where I would start. Check those resistors for bad solder connections and the resistors themsevles with one leg pulled on each (to get a good reading).

Hard to tell by the pic - but that medium sized cap right next to those resistors looks swollen...if so thats gotta go (chances are the whole chassis needs capping).

A shorted diode in my experience will blow the fuse instantly (like a flash). A fuse that warms up and then blows means something is not quite shorted but def bad. I would also try unplugging the degauser coil (black taped looking thing that goes around pic tube) to rule that out.

My guess is that there's several failed caps, just going by the fact that fuse doesn't blow instantly. Could be a bad fly or something else but I'm just logically thinking this out.
 
C36, C38 etc. does not come in bobs cap kit. neither does the 560uf 200v. probably that isnt bad but its lost a bit of its capacitance over time so why not change it.
tried to upload the flowchart for you but its too big. PM me your email and ill send you both including randy fromms flowchart if you do not have.
while ordering from bob, get IC2 and IC1 i case everything else checks out ok.
i checked a good 25k7xxx chassis and IC3 is a nte1773 which seems weird to me cause its a small aperature deflection chip. on some of my other IC3's are nte1797 which are large aperature deflection chip, which kinda makes sense since they are large tubes but then maybe thats why they arent working? i dont know. im just glad i found the nte1773 there and it works and the picture looks good.

time to start checking resistors. also try installing a 2 amp re-setable circuit breaker in F1 so you dont waste money everytime the fuse blows.
 
whoa whoa wait..

you read .5 ohms between pin 2 and pin 3 of the hot???

if so its dead shorted man!!!!

if c36 checks ok, fix any other things that seem shorted, and recheck.. ill almost bet the flyback is arcing of if you look closely mabye its cracked or theres goo coming out of the seams...

if you have a few bad caps, you better just do a full capkit now and get it out of the way.
 
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Thanks for the help guys. I have found all the bad parts(at least I hope) with the help of all your suggestions and am ordering them via Bob right now(Flyback repair kit plus other caps,diodes,regulator and resistors).

I'll let you know when I get them installed if it fixed the monitor or if it blew more parts out. :eek:



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Got the new parts from Bob today. I'll start to rebuild the chassis later tonight after work.

I have to say I really like ordering from bob and the extra's that he packs in. I got a Bob Roberts Calendar. A Mardi Gras Cup with some Moon Pies and some Titty Beads to go with it, which of course I promptly used on the wife.

Anyways, I'll update later on after the rebuild. I borrowed a friends BK 467 to rejuve the tube.

My question is, is the CR23 suppose to fit snug on the pins or can they be a little loose?


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Dude you spent $70 in parts? If you replaced the flyback be sure to turn the brightness up on it as it's usually turned down. You'll need to adjust the focus as well.
 
Ok after $70 bucks in parts this is what I get on the screen(that is suppose to be street fighter II in the background). I replaced all that was bad on the board, so is the tube toast? What do you think?

DSC00996.jpg



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Looks like it is out of synch.
 
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