paperboy-disco monitor med res, not powering up, help please

tron guy

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paperboy-disco monitor med res, not powering up, help please

I am working on this paperboy for another klover. I got the game basically working aside from this damned monitor.

The screen was wacked when I got the game, bad colors, squished picture, but it did work, somewhat.

I recapped it, reflowed solder, etc, with a kit from Bob Roberts. Now Bob's kit had some different caps than were previously in the chassis, but this didn't worry me because I see this all of the time and it seems that Bob is always right.

In particular there were 2 positions.
C107 I pulled a 1uf 16v NP cap, bob's kit had a 10uf 50v cap
C241 had a 47uf 50v, bob's kit had a 22uf 50v

Anyway, when I pulled the monitor I noticed the degauss coil didn't seem to be connected.
moving forward..........
I put the recapped chassis back in the game and voila, killer pic, everything is awesome, boom. awesome shit.
Then 5 minutes later it just shut off. No blown fuses.
The big white rectangle (thingy) on the front left of the chassis is piping hot.
Once I take it out I notice this time that 1 of the pins where the 4 color wires from the yoke connect to the chassis is broken off, it was soldered into place (barely).

So today, I switch the 10uf 50v cap that bob sent (C107) back to a 1uf16v NP cap, and I replace the broken pin where the yoke connects to the chassis. I did not connect the deguass coil this time.
Anyway,same thing, monitor isn't getting power and that white thing is smoking hot.
I don't know how to measure b+ on this thing is that a possibility, that it's too high?

love some help
 

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I thought it worth pointing out that the taller cap in the lower left corner (area) not the shortest one in the very low left corner, it position C241, which previously had the 47uf 160v, but bob says a 22uf 160v goes there (and the 22uf is what's currently in there)

It is positioned right near the B+ adjustment knob. NOt sure if it's relevant, but thought I'd mention it.

Should I find a 47uf160v somewhere and toss it in there?

Bob did tell me through the conversations we had that he needs to re-evaluate the disco cap kit. He went off of a schematic apparently, and didn't have any other info the get his list from.
 
Ok well bob says I should NOT swap the 22uf back to a 47uf, and that if the big white resistor is getting hot, I have a short somewhere.

guess I need to locate a short.
 
should I be measuring the b+? anyone know where to measure on here?

I guess I automatically change the hot just to see.
 
should I be measuring the b+? anyone know where to measure on here?

I guess I automatically change the hot just to see.

Check the HOT with your meter, and see if it's shorted to ground. I don't know what style of HOT that chassis uses.....the "bottle cap" like a G07 or Sanyo, check the case to ground. For the three legged kind like a K7000 series, check the middle leg to ground.

Edward
 
It's not grounded to the frame, I guess I could change it just to see what happens.
 
well I tested the b+ the same way I would test it on a g07.

I was getting 151.0 on the leg of the white resistor closest to the tube, 10.8 on the leg furthest from the tube.



not getting any noticeable power to the tube, it doesn't make the sound you expect to hear when powering on a monitor.

not sure what to do now. any ideas?
 
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well I tested the b+ the same way I would test it on a g07.

I was getting 151.0 on the leg of the white resistor closest to the tube, 10.8 on the leg furthest from the tube.



not getting any noticeable power to the tube, it doesn't make the sound you expect to hear when powering on a monitor.

not sure what to do now. any ideas?


not sure what to look at next on this thing.

not sure if it's relevant, but I did a continuity test on all of the flyback points from one to another. from positions 6-5-4-3-2 (IIRC) they were all shorted to each other.
 
well I went in tonight and installed a 2nd cap kit, just in case I had one in wrong (which I didn't) or one was bad.

didn't change anything

b+ is at 152.0 or so and doesn't adjust with the adjustment pot.

The big white resistor(where you test the b+) is flaming hot.

no neck glow, no picture
 
test that white reisitor and see if its open. Since there isnt a whole of info on the disco I would pull a schematic and start at the begining of the power and look for a bad part. it does sound like a cracked trace or solder caused you said it worked before the cap kit so just by handling it somthing came loose.
 
I don't think I've been able to find a schematic, anyone have one?
 
Hi Tron Guy,

I'm having exactly the same issue with my Paperboy Disco AGM 20M, did you get any further with yours?

jump to 2:03 in the video...
http://www.youtube.com/watch?feature=player_embedded&v=uY5scc5whGU

This is my first ever monitor repair so I am getting very lost in the jargon, electronics are far from my strong suit. :(

I have not messed with it at all, I was thinking of getting back to it. I saw your thread and it made me think of it, but I didn't really read through your thread yet.
My B+ was too high (IIRC) and I am in high voltage shut down. I am going to go in and mess with it soon. Maybe that will take precedence over the 5 other chassis I'm working on right now, adn we can both get ours working.
 
Thanks for replying. I spoke to Chad over at ArcadeCup this morning and have decided to send the board to him, this stuff is way over my head and he seemed really interested to get his hands on an original Disco, so hopefully he can work some magic.
 
Thanks for replying. I spoke to Chad over at ArcadeCup this morning and have decided to send the board to him, this stuff is way over my head and he seemed really interested to get his hands on an original Disco, so hopefully he can work some magic.

Good, he told me before that he had never worked on one. I don't doubt that he can fix it. Maybe now I will wait to work on mine until you get yours fixed and hopefully I can get some insight as to what the problem is.
 
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