NEWB with monitor issue on my first MK3 arcade (video included)

[jermo537]

Whats up fellow arcade brothers and sisters!
I recently purchased my first arcade game, Ultimate Mortal Kombat 3 =) loved this as a kid and had to have me one! so that means you have another newbie on your hands! =(  Anyway found a cheap one that worked well but had a few issues. The last one i cannot tackle is monitor issues. I've taken a video of my issue and posted in youtube at the following URL:



As you can see it looks good when the screen is smooshed down in the beginning of the video, almost like a widescreen. But when i increase the screen to normal size i get that huge horizontal line all the way across and it distorts everything at that line. I've messed with all the controls for the monitor, the controls in the back on the monitor board itself and nothing is working. The sticker on the monitor says Aug 1994 so i'm willing to bet that's my problem ha! Just wondering if anybody can shed any light out there as this is my first arcade project. New monitor? Get a cap kit and install that? Get a new video board? any help would be appreciated! thanks!

[grantspain]

thats the start of a vertical collapse possibly,most likely a leaky capacitor on the vertical deflection circuit
install a cap kit,its a shotgun job but will probably cure the issue

[jermo537]

well thank you sir for the reply! so the monitor tubes themselves never go bad, just the boards and caps huh?
numbers on my monitor are: R-A63ADG25X
serial number: 1096154

[grantspain]

thats the crt number
take a photo of the monitor circuit board to see if we can id it but most likely a wells gardner k7000 series
crt do go bad,you can internal shorts and weak guns but the only time i have seen a similar issue to what you have that was crt related was when someone installed the wrong type chassis on a tube so its unlikely

[jermo537]

well that serial number was on the tube and board in the back, figured that was it. and its not the original midway case just to throw that out there. here are some pics of the cabinet and board for the monitor.

[grantspain]

quite sure thats a 25" k7400 but I would wait for someone else to confirm this is the case as I have not seen one for about 5 years

[jermo537]

any identifying marks on the board itself i can try to locate?!? so we can be absolutely sure...

[grantspain]

there is a sticker on pic 4 nearest the crt

[jermo537]

well...bad news, i just screwed my monitor up im pretty sure! was being careless and trying to clear out cobwebs and accidentally hit the board that connects to the tube. the pins on the tube are all bent. lemme snap a pic and see if its actually repairable. prob not =(

[jermo537]

theres the damage...wtf to do now! buy a new monitor of course but do they come with the boards so it would be plug and play? or should i get just a monitor and use my boards? if i do that tho i would be stuck with the problem i would think

oh and im pretty sure the glass at the end of the tube is broken along with the tab thing at the bottom right...

[MonMotha]

That doesn't actually look broken.  That looks like it was just cut at the factory to make room for the little plastic cap they put on to separate some of the higher voltage pins.  The pins are definitely bent, though, so you'll have to CAREFULLY bend them back into position and re-attach the neck board.

If the glass really is cracked, the tube is done for; you'll have to throw it out and find a new one.  You would have probably heard a loud "hiss" sound if you broke it as the tube lost vacuum.

[jermo537]

oh wow thanks for the good news! i definitely did not hear a hissing sound when i popped that kneckboard off so maybe it is good. i know i cracked the kneckboard a bit where it connects, that plastic seems real brittle. of course it is for its age. well do you recommend discharging the tube before i bend the pins back? actually you called them high voltage pins so ill def discharge it lol if i have to get a new monitor where do you recommend i look and which one should i get?!? very new at this stuff sorry

[MonMotha]

As long as you're not messing around with the anode contact under the "suction cup", there's really no need to discharge it.  By "higher voltage" on the neck pins I was mostly referring to the focus voltage (a few kV) and G2 (~600V), but those are only present when the monitor is on and operating.

No need to replace the monitor if this one works.  This monitor is decent and relatively easily serviced.  New ones are hard to find and very expensive to ship since you're unlikely to find one locally.

[jermo537]

cool sounds good, thank you sir! ill see what i can do to actually get it back to the condition it was before then go from there. anybody recommend a cap kit for this board? tried reading up a bunch and feel like i can do the cap kit, just not sure which one is the right one to buy?!?

[MonMotha]

http://www.therealbobroberts.net/caps.html

Lots of people say Bob is great, though I've never ordered from him.  Someone probably also has a Digi-Key or Mouser cart ready for you to order that way, if you prefer (see one of the pinned threads).

[jermo537]

well i bent the pins back and connected the kneckboard back on and the monitor still works!  to MonMotha haha! guess ill get on that cap kit now since i saw a couple prices of monitors which were $500+. Digi-Key or Mouser cart?!? not sure what u mean by that i apologize

[MonMotha]

There's a pinned thread in this forum of "Mouser cap lists".  They're lists of the capacitors used on various monitors (one list for each monitor) on the distributor Mouser's website.  However, it looks like the k7400 one has a lot of EOL/Not Available parts on it and needs updated.  Probably easiest (and cheapest) to just order from Bob.  He buys in bulk and passes the savings along.

And actually, now that I think about it, I have ordered from Bob before.  He's a great guy, as others say.

[jermo537]

well i bought a cap kit from Bob and replaced 30+ caps. put everything back together and still have the same issue. any ideas anybody because i am fresh out?!?!  thanks!

[BurgerKingDiamond]

theres the damage...wtf to do now! buy a new monitor of course but do they come with the boards so it would be plug and play? or should i get just a monitor and use my boards? if i do that tho i would be stuck with the problem i would think

oh and im pretty sure the glass at the end of the tube is broken along with the tab thing at the bottom right...

You don't know how lucky you are to not have broken the tube. I did the exact same thing to my cab, except mine actually broke, less than 24 hrs after I got it. That really, really sucked.

[mrk8814]

If the chassis has a 50-60HZ pot then with the screen in the distorted state, adjust the 50-60HZ pot till the lines just disappear.

[jermo537]

yeah i checked for that pot and i do NOT have it =(
i have the U2000 board that does not include that pot...bob recommended changing out my LA7850 chip so i guess ill be doing that soon