Help Needed: KT-2914DF with no picture

[eisbar]

Hi everyone, I'm hoping someone can point me in the right direction for the problem I'm having.  I built a cabinet based on the UA II plans and installed a Kortek KT-2914DF in it (maybe branded as a Betson Imperial?), about seven years ago.

The cabinet was for at work, and it stayed behind when the company and I parted ways about six years ago.  Apparently the monitor stopped displaying anything about a year after that, and they just moved the cabinet into storage and forgot about it vs. getting it repaired.

Happily, the cabinet is back with me again, but I now have to deal with the dead screen.

There are no shops locally that repair arcade systems, beyond simple joystick and button swaps.  I took the monitor in to a TV repair shop that said they still worked on CRTs, and printed them off a copy of the service manual.  After three weeks and a $25 diagnostic fee, I got a call that it "wasn't worth repairing because the problem was with the tube".  When I got the actual tech on the phone, he tried to tell me the problem was that the shadow mask had separated from the inside of the tube glass, and that he'd "seen it all the time back in the day".

I figured it was pointless to argue with him, but I call B.S. on this diagnosis.  The monitor stopped working while the cabinet was stationary, and I've never heard of anything but a drop or other hard shock to a tube causing a shadow mask to detach.  In addition, I've seen pictures of what happens when a shadow mask comes loose, and it's blurry images and warped-looking color.  Not a complete absence of picture like I see on this monitor.  I don't think he even looked at the service manual I'd included.

When powered up, you can hear the tube make the typical "CRT crackle" and feel the static on the front of the screen.  The remote control board has its LED light up, so power is making its way through at least some of the system (it's the HOT that sends voltage to the anode in the tube, right?)  I can't get the service menu to display, and hooking up a VGA source does nothing.

Any suggestions where to start?  I'm happy to take pictures and post them, if it would help someone suggest what I should try.

Thanks,

Eisbar

[grantspain]

have you turned up screen volts yet to see if you get a raster
most likely the eeprom has cleared

[eisbar]

No, I thought I'd seek advice before trying things out.  I'm new to monitor repair, although I'm comfortable around electronics, can solder, use a multimeter, etc.

Is the screen voltage adjusted digitally (assuming so, if the value was stored in an EEPROM), or is there a knob somewhere I'd need to turn?  If it's digital, and if your guess about the EEPROM losing the setting is correct, is there a way to adjust it "blind"?  The adjustment menu doesn't come up for me when I press the menu button on the control board.  I've since read that you can get the service menu up by holding UP on the board, while powering up the monitor.  I'm not at home to try, but maybe doing this will trigger voltage to the screen?

Thanks,

E

[grantspain]

on the high voltage transformer(flyback) there are 2(sometimes 3) adjustments,one is marked screen volts and the other(s) are focus
if you can get the screen volts you may just get a very faint osd menu then you can use factory menu to set it up correctly

[eisbar]

Hmm, I think I've made things worse 

By dialing up the screen voltage (only slightly, maybe a quarter turn) I was able to see a faint white glow, sort of a blotch about five inches wide, in the lower right quarter of the screen.  The service menu didn't show, and within about five seconds, I started hearing a nasty hissing noise that I hadn't heard before.  I quickly unplugged, but I assume the noise is a blown capacitor that I'll have to track down and replace before I proceed?  I didn't see any with obviously bulged tops or leaking electrolyte.  Is it safe to plug back in for a few seconds at a time so I can use my ears to narrow down where the hissing is coming from, or should I stick to visual inspection only?  If the latter, any suggestion which caps I look at first, if turning up the screen volts caused one to pop?

Thanks,

E

[grantspain]

you can't blow anything by turning screen volts up,at worst you may sent chassis into shutdown if the screen volts was maxed out
the hissing is possibly ht,it could be from the anode cap and it needs just a clean or it could be the actual flyback transformer is faulty

[MonMotha]

It sounds like you may have turned up the focus, rather than screen.  This will eventually engage a spark gap that's designed to clamp the focus voltage if it goes too high.  Just turn it back down.