Author Topic: Noob with dead monitor plz help (Read 10560 times)

b3dr0ck · « **on:** January 30, 2011, 12:26:42 am »

I bought an Ultracade, it supposedly worked fine, but once it was delivered to my house and we plugged it up, it was "playing blind".

Not know what I'm doing and eager to get it up and running, I nearly blew up all the circuitry inside the cabinet. It's taken me about a month, and I've repaired everything somewhat, and now I'm back to playing blind again.

To me, it looks like the monitor is not getting any power. It doesn't light up at all.

I don't exactly know how everything works, but the circuit board for the monitor has 2 plugs. Looks like one recieves the colors and sync, and the other gives it power. (This cabinet has been upfitted to the Ultracade) Those 5 wires run down to the USBlinx card, and connect via the wiring harness. All of the connections look fine - though they have been spliced and put together.

So, the monitor gets its power from the USBlinx card? Which gets it's power from a standard PC power supply. The cabinet itself has a power cord, but it looks like that only powers the lights in the cabinet. (I'm a newb to all of this, so I'm trying to figure out how it all works so I can troubleshoot it better) I can attach some pics if you like.

grantspain · « **Reply #1 on:** January 30, 2011, 08:19:45 am »

get some pics up of the monitor and wiring etc,as much as you can
you will need a multimeter if you wish to fault find this issue

b3dr0ck · « **Reply #2 on:** January 30, 2011, 10:17:41 am »

Here's pics of the power wiring as much as I can understand. I'll get all the specs on the monitor today.

grantspain · « **Reply #3 on:** January 30, 2011, 10:57:34 am »

thats the video signal wires,one plug is red/green/blue/video ground and the other is the sync
the power wires will come from a transformer in the base of your machine and should read 110-120vac on a multimeter
take a photo of the complete monitor board from the back and i will point out the power wires

qrz · « **Reply #4 on:** January 30, 2011, 12:41:01 pm »

well, it is a WG chassis.

AC input will be on the left side - isolation xformer likely required ( see base of cabinet for stand alone unit )

Ken Layton · « **Reply #5 on:** January 30, 2011, 12:50:37 pm »

You have a Wells-Gardner 25K7191 monitor (requires an isolation transformer).

Your cabinet is originally a Midway, so your ultracade is a conversion kit.

b3dr0ck · « **Reply #6 on:** January 30, 2011, 02:24:46 pm »

OK so just to confirm, the power does not come from what I've shown earlier. It has it's own power source different from the PCB, Ultracade stuff. (That makes sense)

As you can see from the pics, there are spliced wires. I don't know what's what. I do know it worked before it was loaded on the back of a truck and driven 30 miles.

Here are 4 more pics - thanks for your help so far.

b3dr0ck · « **Reply #7 on:** January 30, 2011, 02:28:12 pm »

Here are some more pics

grantspain · « **Reply #8 on:** January 30, 2011, 02:54:23 pm »

that wiring is a bit of a mess
anyway first thing first-get a mutlimeter
then you see the black and white wires that have that label on-they are 120vac power input,you need to trace them and read the voltage where they join

b3dr0ck · « **Reply #9 on:** January 30, 2011, 03:39:48 pm »

I have a multimeter

The block thing at the bottom of the cabinet has
2 yellow wires coming out the left side
2 wires - white/red striped and black yellow striped on right side

I know power is coming through there, cause the light in the top of the cabinet lights up when the power is turned on.

Coming from the monitor power xformer thing there is a wire that splits, see pic, one pair goes down to a pair of plugs that is unplugged.

grantspain · « **Reply #10 on:** January 30, 2011, 04:19:30 pm »

read the voltage on the power plug to the monitor chassis-the one closest to the chassis
set meter on 200vac range and red probe to one of the purple wires and black probe to the other purple-not important what way round

b3dr0ck · « **Reply #11 on:** January 31, 2011, 01:16:33 am »

1 - I unplugged the cable closest to the isolation transformer
2 - I turned my multimeter to V~ 200 (I'm not sure if that is vac)
3 - I put the red probe into one purple side the black probe into the other it read 140.5
(4 - I turned the power off to the cabinet and tried again, it said 00.0)

What does that mean?

grantspain · « **Reply #12 on:** January 31, 2011, 01:57:40 pm »

Quote from: b3dr0ck on January 31, 2011, 01:16:33 am

1 - I unplugged the cable closest to the isolation transformer
2 - I turned my multimeter to V~ 200 (I'm not sure if that is vac)
3 - I put the red probe into one purple side the black probe into the other it read 140.5
(4 - I turned the power off to the cabinet and tried again, it said 00.0)

What does that mean?

read the plug closest to the monitor not transformer
if do have 140vac going in then thats far too high

you have your multimeter set correctly

b3dr0ck · « **Reply #13 on:** January 31, 2011, 04:04:18 pm »

This is making me feel real stupid

The monitor has a circuit board attached to it. See Photo Monitor Power 1.jpg On that board is an ominous looking thing on the left side. It has a ticket saying something, ATTENTION ...., there are 3 wires that come off that side a black, white, and green/yellow striped (which I'm thinking is the ground). I unplugged that plug. Those 3 wires ran into a "molex connector" (not sure if that is the correct term). That male connector plugged into a female purple, green, purple connector. I plugged my multimeter into that purple, green, purple connector. I plugged the probes into the purple female holes (wow did I just type that). It was about 4 inches from the monitor circuit board. I thought it read 140.5.

I read that I should see a glow on the neck when it is on. I am real afraid, I am going to shock the crap out of myself.

Isn't there a fuse somewhere on that monitor circuit board?

grantspain · « **Reply #14 on:** January 31, 2011, 04:30:53 pm »

the white is live,black is neutral-they are the two wires to read-must be 120vac or near
the green/yellow is standard earth wire colour

if it reads 140vac then there is a real problem as thats far too high

yes there is an onboard fuse on the monitor chassis

if you goto the wells gardner website you can download the schematics and circuit board layout-this shows the location of the fuse
you can test the fuse by switching the power to the machine off,then set your multimeter on ohms and place a probe on each side of the fuse-it should read dead short(0.00 to 0.5 ohms)

if the fuse is blown then you need to find the plug with the correct voltage from the transformer

monitors are not easy things to work on and can be dangerous

if you are in any doubt then you will need a professional to work on this

i will look at the pics again as there is some bad wiring on that transformer-perhaps i will spot something

b3dr0ck · « **Reply #15 on:** January 31, 2011, 04:38:41 pm »

Is that anything I could have done? I did blow a fuse in the bottom of the cabinet at one point. (Pls don't make me explain) I've replaced it.

But the monitor is showing the same symptoms as when I got it.

I'll check it again tonight. It was late last night, maybe I misread the multimeter.

b3dr0ck · « **Reply #16 on:** January 31, 2011, 07:54:27 pm »

I just tested the connector again, and tested the other purple wire that isn't plugged into anything bot 130+ vac

shagster · « **Reply #17 on:** February 01, 2011, 01:05:27 am »

Make sure the batteries in the multimeter are good,dunno what that symbol on your meter is (bottom left side),but it looks kinda like a battery warning!
Flat batteries can throw off readings.

b3dr0ck · « **Reply #18 on:** February 01, 2011, 08:31:24 am »

OK - yea the battery was low in my multimeter. I changed it out and tried again.

The connector now reads 128.5

grantspain · « **Reply #19 on:** February 01, 2011, 01:38:59 pm »

Quote from: b3dr0ck on February 01, 2011, 08:31:24 am

OK - yea the battery was low in my multimeter. I changed it out and tried again.

The connector now reads 128.5

right getting somewhere now looks like a chassis fault-now you need to check the fuse on the monitor chassis(remember power off)
the voltage is a bit high but is operational-are you US or UK?

b3dr0ck · « **Reply #20 on:** February 01, 2011, 02:51:03 pm »

The fuse is blown.

I'm in the US

I can't read what it is. From some documentation online it looks to need a
2A 250VAC SB
(2 amp, 250 volt ac, slow blow - if I understand that)

So I go buy a fuse, and put it in. Something blew the fuse right? A blown fuse is a symptom to a problem. Put another one in a try again?

grantspain · « **Reply #21 on:** February 01, 2011, 07:03:12 pm »

yeah 2amp sounds right,is it blown black?if so that means there is a dead short in the primary power supply circuit of the monitor
try another fuse by all means,just don't stand too close when you switch on the power
if it blows violently again then its not a fix for someone without good monitor repair knowledge,it could be a diode/ptc/short to earth degauss coil or voltage regulator ic
time to learn how to discharge,remove safely and pack it off to a repair tech i think

b3dr0ck · « **Reply #22 on:** February 01, 2011, 09:00:14 pm »

From inner hope, to despair in a manner of minutes

I replaced the fuse, and it blew again (black).

Well, I'd like to learn how to repair, and eventually I think I will - but I'd also like to get my first one up and running. So, I guess I'll look for a local tech.

Anyone know how to find a local tech? I'm in the Charlotte, NC area.

grantspain · « **Reply #23 on:** February 03, 2011, 05:00:23 am »

you could try one thing to see if you can get it to run,disconnect the degauss coil and then try with a new fuse

b3dr0ck · « **Reply #24 on:** February 03, 2011, 09:28:08 am »

Yea that sounds great, I'm all for doing everything I can to fix it myself, except:

1. I don't know how to disconnect the degauss coil - I think I know what it is though
2. I'm up to $20 in fuses now, at this rate in a month I could've paid to get it fixed

I've been able to reach a local repair place yet. I called a place yesterday, no one answered, and I left a msg and no one called me back.

grantspain · « **Reply #25 on:** February 03, 2011, 11:10:56 am »

bloody hell your fuses are expensive,I buy about 50 for £3

degauss coil is plugged into the 2 pin header next to the fuse-just unplug it

b3dr0ck · « **Reply #26 on:** February 03, 2011, 01:24:48 pm »

I'm not buying the fuses at a good place, that the problem. It's the price of ignorance. I need to find a place that sells fuses cheaper. I just keep hoping this is the last fuse I'll need.

I've seen that plug, I'll unplug it, replace the fuse and try again.

I called two local repair places today, and they acted like they had never heard of a WG Monitor. I tried to talk to them and it was like I was talking another language.

grantspain · « **Reply #27 on:** February 03, 2011, 02:26:57 pm »

tv repair shops are unlikely to have crt techs anymore,what you should now do is google "discharging and removing a arcade monitor"-learn this then you can send it off for repair to a good professional

b3dr0ck · « **Reply #28 on:** February 03, 2011, 11:37:20 pm »

Well good news, bad news

Good news - I found cheaper place to get fuses! 1000% cheaper
Bad news - I removed the degauss coil, plugged it up - blown fuse.

Question on that - does the fuse have to be a SB - slow blow? Can a "fast-acting" 2A 250V glass fuse work as well?

I've watched lots of videos on discharging a monitor. Some of them multiple times. If the fuse cuts power at that point on the chassis, has power ever made it to the flyback? I've had the monitor a month now. Anyway, I'll discharge it. I can't test anything at this point without removing the the chassis anyway, right?

From all i've read, the next thing to test would be the HOT.

The monitor was working before they loaded the cab up on a truck, and unloaded it. That said, I don't see how moving the unit would shot the HOT. (Then again, I don't really know what a horizontal output transistor is either.)

grantspain · « **Reply #29 on:** February 04, 2011, 03:34:30 am »

any fuse type will do-anti-surge,fast action etc

horizontal output transistor is unlikely to blow the hell out of the fuse,its most likely a diode in the primary psu circuit or the ptc

boardjunkie · « **Reply #30 on:** February 04, 2011, 10:15:59 am »

The #1 most likely thing to whack the fuse on a 7000 chassis is the horiz output transistor. They are not as robust as the to-3 case ones used on the older chassis and are a common failure. Here's how to tell if that is shorted: Set yer meter to continuity (it should beep when you short the leads together). Put one lead on the chassis (anywhere on the metal frame is fine) and touch the other lead to the exposed metal tab of the horiz output x-istor. If you hear a steady beep, its wasted and needs relplacement.

Use the original part, do *not* use the NTE replacement. The OEM part is cheaper anyway......

b3dr0ck · « **Reply #31 on:** February 04, 2011, 10:39:40 am »

Do I have to remove the chassis to test the HOT? (If I did I could send lots of pics)

It's a little tight, I can barely get to the fuse.

And, I'm not exactly sure what blowing the hell out of a fuse is, they are not dark black, some you can barely tell are blown. I did say the one was blown black at one point, not sure if I gave the wrong impression. They are not blowing violently (I cant hear or see them blow, I don't know they blow until I test them, but I can normally see a faint sign of blow)

I really appreciate all the help.

boardjunkie · « **Reply #32 on:** February 04, 2011, 10:50:23 am »

Nope.....just leave it as it sits now and do that test. I was a repair tech in the arcade industry for over 15 years and I saw *lots* of the 7000's with wasted horizontal outs. Occasionally the retrace tuning cap would short as well and take the horiz out x-istor with it, so its not a bad idea to meter the solder pad for the collector of the h-o-t after you remove it just to check for shorts. If you *do* still see a short there, don't even bother replacing the h-o-t until you got that resolved.....it'll just blow immediately.

The fuse is a slo-blo, so they may not violently blow and discolor the glass casing.....although they still can with a dead short.

b3dr0ck · « **Reply #33 on:** February 04, 2011, 03:54:16 pm »

Well ... I'm not trying to mask any ignorance here

I don't know what the HOT looks like or where it is located. I've looked at the chassis diagrams for the K7000s (Which i'm hoping is what I have)

http://www.jstookey.com/arcade/WG_25k7191/
http://www.dosmame.mameworld.info/data/_uploaded/image/dos.other.wg-k7000.pdf
http://www.wellsgardner.com/pdf/Spec/K7000.pdf

(those are the best K7000 diagrams I can find)

b3dr0ck · « **Reply #34 on:** February 04, 2011, 10:09:37 pm »

Hey look at these pics and let me know

b3dr0ck · « **Reply #35 on:** February 04, 2011, 10:13:49 pm »

Look at the bottom of the chassis - that doesn't look right to me

boardjunkie · « **Reply #36 on:** February 04, 2011, 11:16:24 pm »

The horiz output is marked "D1398"...the actual part type is 2SD1398. Its located on the large aluminum heatsink near the flyback.

I can't tell from the pix you posted, but you may have some cracked solder on the board. Reflow any of that you see, and you may need to train your eye to recognize it. Just type "cracked solder" into Google Images and it'll pull up several examples of what your looking for. Add fresh solder to them. Any cracked loose solder joints that look like they have heated up need to be dealt with a little differently. You ned to remove the old solder first, then clean the component lead that was soldered there (it may look dark, you need to use some sandpaper to get it shiny again so it'll take solder properly), then resolder it. This is important because I've seen alot of the 7000 series boards with large holes burned in them from the horiz width coil trying to operate with cracked solder. It never ends well....

b3dr0ck · « **Reply #37 on:** February 05, 2011, 11:34:15 am »

so that brown, discolored spot on the bottom of the chassis is OK?

boardjunkie · « **Reply #38 on:** February 05, 2011, 01:48:46 pm »

The discoloration comes from either a component such as a power resistor that runs hot mounted close to the board, or cracked solder on a component that handles some current. Someone may have taken care of it already since it is a common problem. Its hard to tell without the board being right in front of me.

You may think about just pulling the monitor out and taking it to a TV/electronics repair shop and have them go thru it and replace the lytics and repair the horiz section. Just make sure they know that it *must* be powered thru a 1:1 isolation transformer. Any reputable tv repair shop should have one. I'm not bagging on you, but it seems you are inexperienced at this sort of thing and its possible you may do more harm than good fooling with it.

If you can find a company that still has games on location, they should have a technician who can take care of it as well. Where are you located?

b3dr0ck · « **Reply #39 on:** February 05, 2011, 03:34:12 pm »

I'm with ya. I've already done more damage than helped at this point on the whole cab, but it's been a learning experience, which has been good. I am eager to learn.

I've called two places locally, and they acted like I was crazy or something. If I can find a place locally who I can trust I would take it to them. I'm in Concord, NC, close to Charlotte NC. I know there's likely a good place, just not sure how to find them.

What about if I just buy a replacement chassis board. Looks like they are some on ebay for $40 - $50. If I replace the chassis with something identical, is there soldering involved?

This is an Ultracade it has a VGA output. I might consider putting a VGA monitor in its place. Its a 25" though, and all VGAs now are 6:9.


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