Sharp Image Monitor Troubles - K7000 clone

SnakeRake

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Hey Guys,

First off - just to get it out the way - I know jack about monitors, trying to learn, been watching a lot of videos - will hopefully get there one day.

Anyhow I'm hoping some of you can point me in the right direction. I picked up a Ms PacMan last week that was in really rough shape. I replaced the power cord (2 prong - have a new 3 prong I'm swapping this weekend) on it and got the board to boot to garbage on the monitor - and maybe some collapse( not sure - posting pic below). I repeated this a few times after successively cleaning the edge connector until the monitor stopped showing any picture at all.

Now the Monitor has a slight hum to it, but I get no picture whatsoever. There is no neck glow, but every now and then when I switch the game on I hear the crackly hum of what I think is the degauss circuit.

Its a 19" RCA tube with a Sharp Image Chassis. I checked all the fuses near the transformer and they are all good. I checked the voltage running into the monitor and its 120V AC.

I'm planning to pull the monitor out this weekend to examine it further, and hopefully get a model number off the chassis.

Any of this sound familiar? Any suggestions on next steps?
 

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its probably time for a cap kit which is a usual cause of the partial collapse you have, but since its dead now there may be more to it. best thing is find out the model of chassis or post pictures of it so we can talk specific to your chassis. we stock the cap kits and parts with the best quality caps in them if we find you need anything.
 
its probably time for a cap kit which is a usual cause of the partial collapse you have, but since its dead now there may be more to it. best thing is find out the model of chassis or post pictures of it so we can talk specific to your chassis. we stock the cap kits and parts with the best quality caps in them if we find you need anything.



Thank ya! I just ordered replacement fuse blocks and fuses from ya. Should have waited I guess.
 
Well, seems like part of my problems was the PCB, I got a new board from brzezicki and I got some picture back.



Partial Vertical Collapse?

I pulled the monitor out but I can't figure out what the model is. There is a sticker on one side that says S/No. KTW 21" 95062496.

Sharp Image is printed on the PCB, but the only other identifying marks are is something that looks like a logo with Backwards RU, another P shaped logo then PL-2 and a triangle.

Anyone got any ideas on what chassis this is?
 

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K7000 copy that sharp image had. it should take the same cap kit as the wells gardner k7000.

if you have a partial collapse still check that you have 24v at pin 6 of IC3 and also if you haven't capped it do that and also reflow it.

BTW: is there a number on the side of the flyback??? i am curious if its a k7000 flyback or compatible on it.
 
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Looks like the number on the flyback is D2DH ILI004. That first letter could be a O or 0. not sure. It say DuGo on the top of it as well.

Do you recommend a new flyback as well? And does your cap kit include the extra large cap in the corner? It looks like the top of that one might actually be bulging.
 

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the filter cap is sold separately on our site. all of them are in stock. (560uf 200v). if the flyback is bad or questionable than i would replace it if it takes the standard k7000 flyback. i have never tried it but i am suspecting its the same flyback as the wells gardner k7000. if you replace it please confirm.
 
This one actually has a 680uF 200v Cap.

Is that incorrect? Should I order the 560uF instead?

the filter cap is sold separately on our site. all of them are in stock. (560uf 200v). if the flyback is bad or questionable than i would replace it if it takes the standard k7000 flyback. i have never tried it but i am suspecting its the same flyback as the wells gardner k7000. if you replace it please confirm.
 
I've made some progress with this monitor, I got the Cap kit from Peter at Arcade Parts and Repair, most everything in the kit lined up as a k7000 even thought this is a copy. I installed all of the caps provided except c6 and c50 - I dropped the cap for c6 and couldn't find it, and there was a 35V cap installed at c50, so I didn't want to chance it with the 25V one provided.

I ordered a new flyback, but chickened out on installing, because I don't know how to verify if its the right one. I also installed a new edge connector to rule out any monitor troubles caused by an old connector - the humming speaker is now quiet! I was able to converge the monitor better after I took the video below

The monitor is looking much better, but not sure where to go from here - I have a few apparant problems and I hope someone can give me a little direction on them.

1 - the right side of the picture(top of monitor) skews off at an extreme angle

2 - there is a gentle repeating wave that slightly distorts the picture on the outside edges of picture. The wave runs right to left (top of monitor to bottom)

3 - the horizontal width coil is unresponsive, no adjustments to it make any difference to the picture

Video of current condition
https://www.youtube.com/watch?v=gZOWrK3pwU8&list=PLk2cNG7xxHPKE30H7As8LtcgWJkccDGyn&index=4&t=0s

Edited to include screenshot of video:
attachment.php


- is this the dreaded k7000 curl?
 

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have you checked the pots to make sure they are good and not cracked?? does that chassis have hold pots and if so have you tried adjusting the hhold or frequency pots??
 
I guess I'll pull the chassis again and check the pots, they have plastic covers on them so it's difficult to visually inspect them. I reflowed solder around the connector for the pot daughter board when I did the caps. (Sucked out solder and replaced)

I don't seem to have a frequency pot, I found adjusting the h position and h hold pots lessened the shear into a curl that waves on a off in a constant pattern. I adjusted the v hold to let the screen roll and noticed the curl follows the top of the picture, not the top of the tube. The curl moved with the screen roll

ae70265c2bf02f0a6a6eb9493784e137.jpg


I tried to adjust the width coil and it's still unresponsive, but I noticed if I lowered a metal Allan wrench into it, it would affect the width a little depending on how far the wrench was in. Do I need a new width coil?

And I still have this subtle repeating wave that wobbles the picture as it passes by - could this be some sort of ac interference?
 
1 - Since it is a k7000 clone I'd try the 50/60 pot to fix the rollover at the edge. K7000s have it placed just inside of the main adjustment pots flat on the pcb, check your schematics but I'd guess that black pot in the picture next to j10 would be it.

2 - Search the forum for Ms Pacman Hum Bars or google and see many people battling what you have (more or less). I usually start with edge connector, tossing the RF filter board and upgrading the fuse block. There are tons of other places to look, caps on the board, grounding in the cab, power supply issues... This website has tons of info on Pac PCBs. http://lawnmowerman.rotheblog.com/ and will be a lot of help. The scrambled display on Pac boards booting tells what the error is it is hanging on.

3 - You might have a frozen coil. Sometimes it feels like you're in the right place but you're not actually getting a bite on the adjustment, sometimes it won't move at all and is rusted in place. If you're sure you have gotten the allen wrench in the hole properly and it's moving check the soldering on all the legs of the coil to be sure there is conductivity. If there is and no adjustment is working you can replace it. You really need to have a plastic adjustment tool so you can adjust width while the monitor is hot without shoving a metal bar into an area with high voltage. They're pretty cheap and well worth the price. I use plastic screw drivers when adjusting the pots on my monitors too just in case.

Ms Pac was my first arcade cab and still my favorite - enjoy her!
 
1 - Since it is a k7000 clone I'd try the 50/60 pot to fix the rollover at the edge. K7000s have it placed just inside of the main adjustment pots flat on the pcb, check your schematics but I'd guess that black pot in the picture next to j10 would be it.

2 - Search the forum for Ms Pacman Hum Bars or google and see many people battling what you have (more or less). I usually start with edge connector, tossing the RF filter board and upgrading the fuse block. There are tons of other places to look, caps on the board, grounding in the cab, power supply issues... This website has tons of info on Pac PCBs. http://lawnmowerman.rotheblog.com/ and will be a lot of help. The scrambled display on Pac boards booting tells what the error is it is hanging on.

3 - You might have a frozen coil. Sometimes it feels like you're in the right place but you're not actually getting a bite on the adjustment, sometimes it won't move at all and is rusted in place. If you're sure you have gotten the allen wrench in the hole properly and it's moving check the soldering on all the legs of the coil to be sure there is conductivity. If there is and no adjustment is working you can replace it. You really need to have a plastic adjustment tool so you can adjust width while the monitor is hot without shoving a metal bar into an area with high voltage. They're pretty cheap and well worth the price. I use plastic screw drivers when adjusting the pots on my monitors too just in case.

Ms Pac was my first arcade cab and still my favorite - enjoy her!



Thanks for the info! I tried adjusting the pot you mentioned and it made the image bounce a bit but didn't affect the curl unfortunately. I messed with h-hold a bit more and lessened the curl, but could never get it to go away entirely.

I do have the plastic adjustment set, but they wouldn't turn the coil so I resorted to the wrench in needle nose vise grips with heavy gloves.

And I'll check out the humbar more, thanks, good to know what I'm dealing with! I have already replaced the edge connector, but I wont give up on tracking it down yet.

All that aside i think i'm up the creek now with this monitor.

I pulled the chassis tonight to inspect the pots and swap the 2 remaining caps, and I decided to man up and install the replacement k7000 flyback.

I reflowed solder around the pots on the adjustment board, swapped the 2 caps, then installed the new flyback. Everything went smoothly, I double checked my work then hooked it back up to the tube.

I flipped the power on and saw a white flash in the neck and a puff of smoke come from near the flyback. I think another flash came from the chassis, but I may be remembering wrong. The 3v fuse on the board had blown when i inspected it.

I did some cursing then headed up to bed.

So have I screwed the pooch? Fried the board? Ruined the tube?
 
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I do have the plastic adjustment set, but they wouldn't turn the coil so I resorted to the wrench in needle nose vise grips with heavy gloves.
That is a pretty good sign the width coil is seized. You can try spraying some Deox-it in there to see if it will free up. Using full weight tools will stress the solder and can easily cause cold solder joints, the coils aren't super heavy-duty and can break fairly easily.

And I'll check out the humbar more, thanks, good to know what I'm dealing with! I have already replaced the edge connector, but I wont give up on tracking it down yet.
Replacing the fuse block has fixed the bars 9/10 times for me.

So have I screwed the pooch? Fried the board? Ruined the tube?
We've all been there! Learning to work on monitors will always start with a few screw-ups! You probably didn't damage the tube and just killed a few components on the board. Did you have the chassis grounded? The dag wire needs to be on from the neckboard to the tube. Maybe a cap in backwards? Read up on the k7000 faq thread in the monitor section. It's super helpful. The Randy Fromm monitor repair flowchart is great too. You might have blown a few things, but you can always fix them.
 
That is a pretty good sign the width coil is seized. You can try spraying some Deox-it in there to see if it will free up. Using full weight tools will stress the solder and can easily cause cold solder joints, the coils aren't super heavy-duty and can break fairly easily.

I should have mentioned I tried that and it did turn once I tried the metal allen wrench after a deoxit soak - when I was installing the new flyback I noticed that one of the solder joints on the coil looked like it might be cold, so I resoldered it - I don't know if that fixed anything since the big bang happened when I plugged it back in.

Replacing the fuse block has fixed the bars 9/10 times for me.
Good to know thanks! I have fuse bloacks and fuses ready to go - just haven't got to it yet

We've all been there! Learning to work on monitors will always start with a few screw-ups! You probably didn't damage the tube and just killed a few components on the board. Did you have the chassis grounded? The dag wire needs to be on from the neckboard to the tube. Maybe a cap in backwards? Read up on the k7000 faq thread in the monitor section. It's super helpful. The Randy Fromm monitor repair flowchart is great too. You might have blown a few things, but you can always fix them.

haha, yeah - screwing something up is usually a good way to learn, just an expensive way.
I made sure to ground the chassis when I discharged the tube again before I tried to put the anode back on. The neck board ground wire was hooked up - and the brush is making good contact with the dag. One of the caps I replaced was BP, so that shouldn't have been an issue, and the other one I'm positive is in correct, I double checked with before and after pictures.

My guess is that the new flyback wasn't compatible, since this is a clone board, it was just an educated guess from Peter of what flyback I should use( the K7000 one he sells). I'll shoot Peter at Arcade Parts a message and see what he thinks.

I have a Universal Chassis coming today, so hopefully I can use it to verify if the tube is still good.

As far as finding what components might have blown - I suppose I need to go component by component and check them? What types of components are more likely to be burnt out?
 
did you replace the BP cap with another BP or NP cap??
 
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