K7191 blows fuses lol

mecha

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I wanna just say first that I have thrown everything but the kitchen sink at this chassis. New flyback, new HOT, new C36, new C38, new VR and I tested every diode on this thing and they all checked out. I went to test D18 and one leg just ate up the solder pad, but I got the same reading in-circuit before I pulled it as I did afterward when I scraped some trace to solder that half to just as a precaution.

I tested again after that with the degauss coil unplugged and it blew the fuse again. This is for a Suzuka 8 Hours 2 we sold and I have to get it working again by weeks end.

And before anyone asks, yes I used the insulators on the HOT and VR.
 
did you check the filter cap to see if its shorted. i have seen several chassis with this problem.

test
C37 out of circuit.
C62 out of circuit, cause in circuit it will read shorted.
diodes D12-13.
as well as D16-17.

some of this you may have checked but check it again to be sure.

Peace
Buffett
 
ugh. another hell popper as i call em.

You might want to give another chassis a try. I dont have any available right now unfortunately.
 
did you check the filter cap to see if its shorted. i have seen several chassis with this problem.

test
C37 out of circuit.
C62 out of circuit, cause in circuit it will read shorted.
diodes D12-13.
as well as D16-17.

some of this you may have checked but check it again to be sure.

Peace
Buffett

any particular way I can check those without an ESR meter? just a continuity check I guess?

I wanna say I pulled the filter cap from another chassis... I'm not particularly certain HOW THE FUCK that happened, but when I was testing this 7191 (and didn't work) I put the chassis that I yanked from my Street Fighter cab back in and it started blowing fuses too. that chassis was fine until then, so I started pulling parts from it, even though it doesn't work anymore lol

also the 7191, the big resistor on the side was cracked in half. I changed that out with another one, but is there anything that can b0rk?

inevitably I'm probably gonna have to snatch the chassis back out of my MK2 to do this. which means I have to start fixing Polos next..
 
test everything with continuity or the beep setting whichever you have on your meeter.

those parts should all read open in circuit except C62 that will read shorted in circuit test it out of circuit to see if its shorted or open. you want it open out of circuit.

if all else fails i have a fully rebuilt 25" full cap out with new fly.
pm me if you want to trade that in on it.

i also have 19"s with a full cap out with new fly.
and one's with the old fly's if you dont need one with a new fly on it.

just for grinns check the 6 rectifier diodes again to be sure.

also check and unplug your marquee lite as you said that you swapped another chassis into the game and it blew fuses to.
something doesn't seem rite to me. maybe you have a short in the cab that's getting to the monitor. does the game play blind without the monitor plugged in??

good luck on finding your problem keep us up to date.

Peace
Buffett
 
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test everything with continuity or the beep setting whichever you have on your meeter.

those parts should all read open in circuit except C62 that will read shorted in circuit test it out of circuit to see if its shorted or open. you want it open out of circuit.

if all else fails i have a fully rebuilt 25" full cap out with new fly.
pm me if you want to trade that in on it.

i also have 19"s with a full cap out with new fly.
and one's with the old fly's if you dont need one with a new fly on it.

just for grinns check the 6 rectifier diodes again to be sure.

also check and unplug your marquee lite as you said that you swapped another chassis into the game and it blew fuses to.
something doesn't seem rite to me. maybe you have a short in the cab that's getting to the monitor. does the game play blind without the monitor plugged in??

good luck on finding your problem keep us up to date.

Peace
Buffett

here's some tl;dr, but people ask for details so here goes... the 7191 in question was pulled from a T2 cab we've since sold... I used that tube + one of the chassis I pulled from this Suzuka to go in my MK2 cab since it didn't come with a monitor, and that was all I had at the time. it's nothing to do with cabinet wiring on the Suzuka, or any of the other games, since the K7000s in those all work fine. I found this one literally dangling by the neckboard in the T2 when I got it in a trade deal, so who knows what happened to it before I got it.

this 7191 has been tested now in 3 different cabs. my Street Fighter cab had a 7171 in it that got a hole blown in it from a dead flyback a couple years ago that I'd managed to repair, to the dismay of probably anyone that's heard of its legend on here lol.. but yeah, the only easily accessible cab I had to try the 7191 in after I replaced like everything was the SF cab, the 7191 didn't work and made this noxious burning plastic smell (probably from the cracked resistor, R301 is it?), so I put the 7171 back in and the same shit happened! it was weird, but that probably had some pins that grounded to the frame, why I didn't think to cut those when I performed surgery on it, I don't know.

I'll take a gander at those other caps though. the diodes I all pulled entirely out of the chassis to test, only got current one way, and of course I reinstalled them in the correct directions.

I did some searching on google earlier and over at arcadecontrols someone suggested checking a C69 too, "if it had it", this 7191's very different from the 7171's I'm used to seeing, it doesn't even have the 50/60 pot on it. could this have a C69? I looked everywhere and couldn't find it.
 
i dont think the early models had a C69.
i have only seen them on the later models.

so if i understand you correct you put the original chassis back in and it smoked the fuse. if it did then you may have damaged something in the cab to make it pop the fuse on the original chassis that was in there and working fine. and now its not. something else has happened.

i would check everything in the test cab and make sure there is not a short some where now.
get the game back running with the original monitor and chassis to eliminate a new problem that may have happened.

then measure everything again on the chassis you are trying to fix and test it again in the verified working game.

that is what i would do if i was having the problems your having.

you should build a test bench for this kind of thing. it will eliminate messing up working games. and its really simple to build. i use mine almost daily and i love it.

good luck and keep us updated.

and if you give up on it. i would like to take a crack at fixing it to learn from it.

Peace
Buffett
 
I'm sure it's an easy thing you're missing. usually a blown fuse will be due to C38, IC4, or D20/D21 shorted, but sometimes a bad HOT, IC3, etc can do it too (especially if you don't use insulators on IC4 and the HOT). And not hooking up the dag wire or using an iso can blow the fuse pretty quick, too.
 
I'm sure it's an easy thing you're missing. usually a blown fuse will be due to C38, IC4, or D20/D21 shorted, but sometimes a bad HOT, IC3, etc can do it too (especially if you don't use insulators on IC4 and the HOT). And not hooking up the dag wire or using an iso can blow the fuse pretty quick, too.

IC3 is the only thing that hasn't been altered or touched. I mean, maybe something else took out the new HOT I put in too, I changed C36/C38 after I put that in. I'll give that a whirl next.
 
Swapped the HOT and filter cap with known working ones and no change.

Anyone know if radio shack carries the kind of pots that go on the K7000 remote board, because I have nothing to swap in to replace the ones I broke.

I could alternatively take a road trip to Frys too. Please someone respond before the morning, running out of time here.

I forgot to check C62. I went back to the thread earlier to see what I had to check and conveniently overlooked that one. I assume thats the heat sensor for the degauss circuit?
 
i have them if you want to get the ones you need.

i don't think rat shack will have them but you can try.

just pm me if want mine.

Peace
Buffett
 
I have a hunch that C62 could be what's bad, it just looks shitty.

If I didn't promise the people I'd have the game working by Friday I would take you up on your offer. Instead I will more than likely just replace the remote with the stationary pots on my parts chassis... I broke the v-hold pot on the remote, the remote one is rated at 500k but the stationary is 200k. I guess it doesn't really matter considering I got the hold locked in, another one of the pots is probably broken though cause I have a scrunched picture vertically just like I had before. Its hard to explain now, I just ran out of time and didn't get to tinker with it more. Too many friends at work distracting us tonight lol
 
ok no prob.

if you want them rushed pay the over night rate and ill get them in the mail today.

just beware that if the pot for your synk gets bumped around in transport it could go out of synk and you would have a service call to do.

if you're replacing the pots on the remote board they are 9mm the pots on the chassis are 6mm.

Peace
Buffett
 
Im REALLY stuck on this one. I dont have another donor IC3, the one in my parts chassis is different and I read theyre not interchangeable. How do you test stuff like IC3 and the voltage regulator anyway?

Btw, i tried everything else, they all tested good. Still blows fuses.
 
this thing is a head scratcher for sure.

i wish i had it to find out the fix. its bugging me for sure.

i have several different types of the IC3 transistors.
what is the PT# of the one you have.

other than checking for power on it i don't know if you can test them with a meter.

but your fuse blows so you wont be able to check for power.
i think it is pin 6 or 7 on the IC.

but i haven't heard of IC3 blowing fuses before.

Peace
Buffett
 
this thing is a head scratcher for sure.

i wish i had it to find out the fix. its bugging me for sure.

i have several different types of the IC3 transistors.
what is the PT# of the one you have.

other than checking for power on it i don't know if you can test them with a meter.

but your fuse blows so you wont be able to check for power.
i think it is pin 6 or 7 on the IC.

but i haven't heard of IC3 blowing fuses before.

Peace
Buffett

mod said to check IC3. could I theoretically run the chassis without IC3, and just have vertical collapse?

I don't have it with me, I'll have to get back to you on that one. as it stands now, I got Suzuka running perfectly fine and I adjusted both monitors to the best I could. that chassis I just threw in it was a MAJOR PAIN IN THE ASS to adjust having the controls on the chassis instead of the remote lol

guess my "supergun" monitor will get dropped in the MK2 and I'll cast this tube into the storage pit until I resurrect this chassis. I have an extra Midway iso I can use for diagnosing it later I guess.
 
I'm running out of things to switch out. at this rate I'd have better chances of getting the one I'm chopping for parts running again.
 
If you're not getting shorts between any of the pins, then I doubt you are blowing the fuse due to IC3.

You HAVE made sure you don't have a shorted yoke, right? Have you tried it without the degaussing connector?

Check those diodes along the wall behind the flyback - D13/D14 I think they are, and D18, C38 again, IC4 again, D20/D21 again, etc...
 
If you're not getting shorts between any of the pins, then I doubt you are blowing the fuse due to IC3.

You HAVE made sure you don't have a shorted yoke, right? Have you tried it without the degaussing connector?

Check those diodes along the wall behind the flyback - D13/D14 I think they are, and D18, C38 again, IC4 again, D20/D21 again, etc...

this is gonna sound stupid, but what does a short read as again? heh

the yokes on all my K7000 tubes are fine. I've been interchanging chassis on all of them and this is the only chassis that goes pop. and yes, I did it with degauss unplugged and it still popped.
 
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