Dead Monitor 101 -- Where to begin?

[Flack]

I got a free game donated to me a month or two ago. It's a conversion MK game. Game powers up and plays completely dead. Monitor doesn't fire up at all.

Where to begin?

[Arcade Antics]

Visual inspection always comes first. Really take a good look at everything, several times. Is anything missing? Any connections broken? Look for all the really simple stuff first, the really obvious stuff. If completing that yields no easy answer, time to start troubleshooting. But stonic and some of the other guys are probably better equipped to take over from here. ;)

More easy stuff to check - fuses (test continuity, visuals on them can often be sketchy), see if back of monitor has the tell tale glow, could be the neck board, might not be getting power, etc. Whatever you do, don't start puttering around with the monitor until you discharge it first.

With everything else working, fixing the monitor up shouldn't be too tough a task overall. Though I've got a cocktail monitor that's been bad forever... but those buggers are tough to get at.

[DogP]

First, you need to know what model the monitor is ;) . After that, I'd go find the flow chart for that monitor. Then follow the flow chart and it'll usually tell you what's wrong :) .

In general though, check the fuses, do you hear the monitor do anything when you turn it on (high voltage or not), does the monitor have neck glow, etc.

DogP

[ClubNinja]

I have to agree with everything that's been said here:

Is there neck glow? Does the monitor hum? Are all connections from power to monitor good? Are all connections from harness to monitor good? Are all fuses good? Etc.

[98PaceCar]

Also, if it happens to be a GO7, make sure you discharge the dummy lug before you mess with it. Trust me on this one...

[Flack]

There is nothing that I can find that identifies the monitor model from the back. There's no glow and no hum; it's like it's not getting any power at all, but when I test the power wires coming from the power supply it's got power. I can't see any obvious fuses on the back of the monitor.

I'll take a couple of pictures later this afternoon and show you what I'm seeing so far.

[Flack]

Ok, minor update, but not really.

Earlier in the week I purchased the complete set of Randy Fromm's Arcade Repair School from FABombJoy. I have to say, just watching the videos has really boosted my courage and knowledge level. I haven't done any more on the project, but at least I'm not afraid to get in there and start poking around now!

One question ... when you guys "cap" monitors, do you pull the boards out with the monitor chassis still in the cabinet, or do you pull the whole monitor out? I haven't quite figured out a good way to do that yet.

I still haven't figured out a model of the monitor yet either -- is that likely to be on the board? I'm going to head out to the arcade right now and do some more poking around. I'm really pumped about starting to work on my machines!!

EDIT: I still can't determine a model number, I'll post a picture tomorrow. The tube says Samsung but I knowt that's not the monitor model now. I don't see anywhere on the board where it's labeled. The right hand side has the high voltage transformer, and all along the back side are all the pots. They are numbered like 104, 401, 402, etc, but I can't see a brand name anywhere on it.

The game was working but isn't now, so I'm looking for something that "went out", not any parts that have been removed or whatnot. Also, I checked and there's no hum, no glow, no nothing. Tomorrow I'll go back out with my meter and start checking what I can.

[Arcade Antics]

One question ... when you guys "cap" monitors, do you pull the boards out with the monitor chassis still in the cabinet, or do you pull the whole monitor out? I haven't quite figured out a good way to do that yet.
I've always pulled the entire monitor out of the cab, set the monitor down at a workstation (could be your kitchen table, just somewhere where you can set it down and get at it), then removed the board and recapped it.


EDIT: I still can't determine a model number, I'll post a picture tomorrow. The tube says Samsung but I knowt that's not the monitor model now. I don't see anywhere on the board where it's labeled. The right hand side has the high voltage transformer, and all along the back side are all the pots. They are numbered like 104, 401, 402, etc, but I can't see a brand name anywhere on it.
Best way to attack that one is to post pics. :)


The game was working but isn't now, so I'm looking for something that "went out", not any parts that have been removed or whatnot. Also, I checked and there's no hum, no glow, no nothing. Tomorrow I'll go back out with my meter and start checking what I can.
Sounds like the monitor isn't getting any power. Could just be a blown fuse, but once you do a prelim scan with the meter you'll know more.

[DogP]

For identifying the chassis, I'd compare to pics here: http://www.homearcade.org/BBBB/monitor.html . I'm not sure from your description, but it's either a WG K4600 if you mean the flyback is seperate from the chassis and hanging on the right side of the frame, or just about any model since they all pretty much have pots on the back and lots have the flyback on the right side of the PCB ;) . The K4600 is easy to identify since it's the one that has the sub-boards.

Anyway, for just about every monitor, I just pull the chassis out of the machine, although with the K4600, I either work on it while it's still in the machine, or pull the whole monitor out, since that one is a pain to remove the chassis from the frame.

DogP

[Flack]

Here are pictures I just took.

http://www.robohara.com/pix/junk/monitor1.jpg
http://www.robohara.com/pix/junk/monitor2.jpg
http://www.robohara.com/pix/junk/monitor3.jpg

EDIT: My looking at that site DogP, so far it seems to most closely resemble the Korean ones, although I'm not sure which ones just yet.

EDIT2: I think I found it.

http://www.homearcade.org/BBBB/kortek.html

[DogP]

Yup... looks like a Kortek to me. I may have some repair info on them at home if you need anything.

DogP

[freckledpeas]

Ok, minor update, but not really.

Earlier in the week I purchased the complete set of Randy Fromm's Arcade Repair School from FABombJoy. I have to say, just watching the videos has really boosted my courage and knowledge level. I haven't done any more on the project, but at least I'm not afraid to get in there and start poking around now!



After looking at your posted pics, I actually have that monitor in my Chase HQ cab! (I know this doesn't help you at all, but I just felt a moment of comraderie and had to share).

Secondly, I'll try not to deviate from your thread topic too much, but I've not heard of "Arcade Repair School" videos... I am very interested... Where can I find these and for how much $? :)

[Flack]

Ok, minor update, but not really.

Earlier in the week I purchased the complete set of Randy Fromm's Arcade Repair School from FABombJoy. I have to say, just watching the videos has really boosted my courage and knowledge level. I haven't done any more on the project, but at least I'm not afraid to get in there and start poking around now!



After looking at your posted pics, I actually have that monitor in my Chase HQ cab! (I know this doesn't help you at all, but I just felt a moment of comraderie and had to share).

Secondly, I'll try not to deviate from your thread topic too much, but I've not heard of "Arcade Repair School" videos... I am very interested... Where can I find these and for how much $? :)

The arcade school is Randy Fromm's. The DVD's aren't cheap from his site (I got them from the forums here) but so far I am very impressed with them! They are great for a dummy like me.

http://randyfromm.com/

[freckledpeas]

Thanks for the info, Flack. You weren't kidding... those dvd packages cost a pretty penny. A good education always comes at a price, though.

[Flack]

Forgive my baby steps. Here's what I found tonight, using a volt meter for the first time in my life. :)

The power cable comes in the back of the machine and splits out into some sort of power distribution block. Tested there, I get 139 volts (?). I'm wondering if the battery on my volt meter is bad (it's likely 5 years old and never used). The power splits off to a hacked up PC power supply. The leads right off there show 5.9v. I tested at the JAMMA adapter and got 5.78v. I don't see any way to change the voltage on the power supply.

Up near the monitor there's a connector that's connecting the power wires running up to it. It also tests at 139v, which means either my voltmeter is consistantly off (possible) or something weird is going on!

I'm not sure what (or where) to test next on the monitor. I'm thinking the high voltage unit would be next but there's kind of a guard around it so I'm not sure where/how to reach/test it.

[98PaceCar]

Forgive my baby steps. Here's what I found tonight, using a volt meter for the first time in my life. :)

The power cable comes in the back of the machine and splits out into some sort of power distribution block. Tested there, I get 139 volts (?). I'm wondering if the battery on my volt meter is bad (it's likely 5 years old and never used). The power splits off to a hacked up PC power supply. The leads right off there show 5.9v. I tested at the JAMMA adapter and got 5.78v. I don't see any way to change the voltage on the power supply.

Up near the monitor there's a connector that's connecting the power wires running up to it. It also tests at 139v, which means either my voltmeter is consistantly off (possible) or something weird is going on!

I'm not sure what (or where) to test next on the monitor. I'm thinking the high voltage unit would be next but there's kind of a guard around it so I'm not sure where/how to reach/test it.

You're getting 5.78 on the 5v rail at the jamma connector? If so, you need to either turn it down or replace that power supply. I aim for 5.05 and no more than 5.1. Much more and you are stressing components.

The monitor should be getting full line voltage to it, so I'm with your theory of the meter being off (ie, 139 is higher than I've seen on a typical AC line in a house). Do you have access to a known good meter? That might also explain why your 5v is so hot.

As far as I know (and correct me if I'm wrong here Pat), you can't really test the HV without an HV probe. I don't believe a multimeter will do it. You've pretty well established that you have power to the monitor though, so I'd start looking for obvious things on the chassis itself. I'm sure you've done this already, but is there a fuse and have you checked continuity across it?

[Flack]

You're getting 5.78 on the 5v rail at the jamma connector? If so, you need to either turn it down or replace that power supply. I aim for 5.05 and no more than 5.1. Much more and you are stressing components.

The power supply looks like (and I assume is) an old ATX power supply out of a PC. I don't know of any way to adjust it. Is there one? Unfortunately I don't have any spare parts, except out of other working machines I own. I am going to replace the 9v battery in my meter tonight and see if that gives me better readings. Is there a simple way to test a meter's calibration? I've tried it in 2 different AC sockets around the house and am getting 139v. I assume that should be 120v, so I think that might be a good test.


As far as I know (and correct me if I'm wrong here Pat), you can't really test the HV without an HV probe. I don't believe a multimeter will do it. You've pretty well established that you have power to the monitor though, so I'd start looking for obvious things on the chassis itself. I'm sure you've done this already, but is there a fuse and have you checked continuity across it?

To me it "feels" like a fuse since it's got power but it's dead dead, but I don't see one. Would it look just like a normal fuse (pic (http://www.hydropool.com/images/parts_spa/spp400/MDA-20-FUSE-5.jpg))? I guess I need to see if I can track down the schematics and see if there's a fuse on the board. Right? (SO new at this.)

[FABombjoy]

139V? I'd think your light bulbs would be going out on a routine basis. I'm betting on the VOM.

120/139 = .86

.86 * 5.78v = 4.97v

I'm guessing that your VOM is reading 16% high. Maybe it's been changed to metric volts ;)

[98PaceCar]

The power supply looks like (and I assume is) an old ATX power supply out of a PC. I don't know of any way to adjust it. Is there one? Unfortunately I don't have any spare parts, except out of other working machines I own. I am going to replace the 9v battery in my meter tonight and see if that gives me better readings. Is there a simple way to test a meter's calibration? I've tried it in 2 different AC sockets around the house and am getting 139v. I assume that should be 120v, so I think that might be a good test.

To me it "feels" like a fuse since it's got power but it's dead dead, but I don't see one. Would it look just like a normal fuse (pic (http://www.hydropool.com/images/parts_spa/spp400/MDA-20-FUSE-5.jpg))? I guess I need to see if I can track down the schematics and see if there's a fuse on the board. Right? (SO new at this.)

It could very well be an old pc supply. Most of those are self regulated and non adjustable. I'd look towards the meter first though, it does seem like it's reading off.

As far as the fuse, I've never seen a fuse on a monitor that didn't resemble a standard fuse.

Does the power for the monitor plug directly into the board or does it have a pigtail from the chassis? If it's a pigtail, check the voltage on the monitor side of the connector. I've seen those stretch out before and cause a monitor to not work.

Past that I don't know a whole lot about the Kortek monitors. You could try a cap kit, but the effort would probably be wasted as I can't think of any way a cap would cause the whole thing to not work.

Dumb question, is the anode hooked up to the tube? (please discharge it before you touch it though....)

[DogP]

Yeah, definately replace your battery on the multimeter... the highest reading out of a wall I've ever gotten was 125, and I was worried about that being too high :P .

You did test it directly out of a wall socket, correct (carefully stick the probes directly into the outlet)? I have seen it where someone hooked up the isolation transformer incorrectly (hooked it up to the Japanese power lugs, which are 95V or 105V or something), which then steps the voltage up to 120, but if 120 is coming in, it steps it up to 140ish. That would probably work for a while, but fry stuff prematurely. It could also up the B+ voltage on the monitor and cause the monitor to go into HV shutdown (basically acts dead, but is really a safety feature). I would guess your multimeter is wrong though, since the game probably wouldn't be playing blind at almost 6V.

And yeah... don't try measuring the HV with the multimeter... you'll fry the meter and probably shock yourself. You should be able to hear whether you've got HV or not (static sound like when you turn ona TV)... you only really need a HV probe if you're going into deeper troubleshooting than why a monitor isn't working.

For finding the fuse, follow where the AC power comes into the monitor, and it'll probably be pretty close to that. They're usually glass with two metal ends, not usually ceramic like the pic posted though. Sometimes they're mini fuses too, so look for either one.

If your power supply really is outputting 5.9V, let me know... I've got a bunch of extra adjustable power supplies, I could send you one for whatever shipping is.

DogP

[Flack]

Minor setback. I opened my multimeter and the 9-volt battery was completely corroded and had rotted the contacts that held it in place. When I removed the battery all the wires and the fabric thing simply fell out in pieces. (insert sad trumpet sound here). Sooooooo ... looks like I'll be picking up a new multimeter in the morning from rat shack. To be honest I don't even know where this one came from.

[DogP]

Ugh... don't buy one from Radio Shack... every one that I've used from there has been pretty crappy... Sears has a pretty good selection, and they have some pretty good prices too. Wal-Mart also has them in the auto department, but they pretty much suck :P .

DogP

[MoreEbolaForYou]

the last multi meter i got from radio shack broke before i even got to use it. then when i asked if i could return it their reply was "no". probably my fault since i sat on it for 3 months before trying to return it, but hey, still crappy.