Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: kardenm on April 29, 2015, 01:31:51 pm

Title: No Picture Kortek Monitor
Post by: kardenm on April 29, 2015, 01:31:51 pm: Need some suggestions. Have a Kortek K1-2-V0 monitor with no picture (black screen).
There is HV and glow in the tube neck. I've tested all the transistors (including HOT), all diodes and all large resistors and checked for bad solder joints.
Not sure where to go now. Suggestions would be appreciated!
Title: Re: No Picture Kortek Monitor
Post by: grantspain on April 30, 2015, 06:54:42 pm: do you have a schematic?
Title: Re: No Picture Kortek Monitor
Post by: kardenm on May 01, 2015, 08:10:08 am: Yes I do. I have a schematic and I know (pretty much) how to use it :D
Title: Re: No Picture Kortek Monitor
Post by: grantspain on May 01, 2015, 05:41:06 pm: fancy sharing it with me then
Title: Re: No Picture Kortek Monitor
Post by: mgb on May 02, 2015, 09:05:19 am: If you crank up the screen knob do you see raster traces?
It may seem obvious but I've always learned troubleshooting is about trying the simplest things first.
Is the video connection good and is the gameboard putting out video?
Title: Re: No Picture Kortek Monitor
Post by: kardenm on May 04, 2015, 05:04:54 am: WILL DO GRANTSPAIN, soon as i can take a photo and post for you.
Title: Re: No Picture Kortek Monitor
Post by: kardenm on May 04, 2015, 05:07:55 am: Thanks mgb.
1-no raster traces.
2-video connection is good and the board IS putting out video. I connected the video to another monitor and works fine.
Title: Re:New Info! No Picture Kortek Monitor
Post by: kardenm on May 05, 2015, 03:32:15 pm: Turns out the Chasis/board is not the problem. It's the tube!
I swapped in an identical board from another cabinet that does work and no picture.
I am getting some glow in the tube neck but it is weak compared to the working tube.
Is this something that can be fixed or is this tube junk? I don't see any obvious damage, broken wires, etc. :dunno
Title: Re:New Info! No Picture Kortek Monitor
Post by: mgb on May 05, 2015, 11:50:17 pm: Quote from: kardenm on May 05, 2015, 03:32:15 pm
Turns out the Chasis/board is not the problem. It's the tube!
I swapped in an identical board from another cabinet that does work and no picture.
I am getting some glow in the tube neck but it is weak compared to the working tube.
Is this something that can be fixed or is this tube junk? I don't see any obvious damage, broken wires, etc. :dunno

Just to be certain, were you also abe to test the questioned chassis board with the known good tube?
Title: Re: No Picture Kortek Monitor
Post by: epicfatigue on May 06, 2015, 07:47:58 am: You have an open resistor in the flyback section :)

Check one of the 1ohm 5watt resistors it will be open :)
Title: Re: No Picture Kortek Monitor
Post by: kardenm on May 06, 2015, 02:36:21 pm: Yes mgb. I put the "bad" chassis with a good tube and got a good picture.

epicfatigue: Certainly I will check these resistors (pretty sure I already did) but they must be good since the chassis works with a known, good tube. Right?

Thanks for the input!
Title: Re: No Picture Kortek Monitor
Post by: epicfatigue on May 11, 2015, 06:46:15 am: Quote from: kardenm on May 06, 2015, 02:36:21 pm
Yes mgb. I put the "bad" chassis with a good tube and got a good picture.

epicfatigue: Certainly I will check these resistors (pretty sure I already did) but they must be good since the chassis works with a known, good tube. Right?

Thanks for the input!

Oh well ill be normally, you see some blue arcing in the neck when its a bad tube, thats if its de vaccumed. If its because of a dead short you can isolate the ground from the neck, and create a new G2 voltage from the flyback if you really want too.

Otherwise check the yoke windings if its not a dead short you can take the yoke off and keep it as a backup or do a yoke swap with a TV from the side of the read, takes abit but well worth it :)