Tatung VS 20475 Mystry Wire

[mantaramian]

Hello NLG Members,
 
 I currently inherited Tatung VS 20475 video slot monitor from a friend of a friend with a few problems.... So I thought I would start with a cap kit. WOW a ton of caps.....
 
 While replacing the caps I found a couple wires that were either broken and obvious to where they belong but I do have one particulate wire in question....
 
 One end of the wire is soldered to C608 but for the life of me I cant seem to determine where the other end should be soldered to.... It can only go to a certain area of the chassis due to its length.....

Does anyone have the same monitor to confirm its position to be soldered to?

See pictures
 
Thanks Mike
 

[Merlin]

I think this might be the schematic for your monitor.


http://www.meritind.com/Support_Center/Type%2066.jpg


See pin 8 of IC601 / LA7851 - c608 is listed

[mantaramian]

Yo Merlin, thank you for the schematic... I have been trying to follow this and I am stumped..... Every time I believe I find the location to solder I start questioning myself....

So I decided to hook up the monitor with out the wire connected. Upon firing the monitor up I got a flat line which leads me to believe tho horizontal transistor is shorted out?

Any thoughts?

[Merlin]

Yo Merlin, thank you for the schematic... I have been trying to follow this and I am stumped..... Every time I believe I find the location to solder I start questioning myself....

So I decided to hook up the monitor with out the wire connected. Upon firing the monitor up I got a flat line which leads me to believe tho horizontal transistor is shorted out?

Any thoughts?

My CRT repair experience is limited, I am sure someone smarter than me can chime in and tell
you exactly what to look at. I found some posts on nlg.net which might be helpful to you:


http://newlifegames.net/nlg/index.php?topic=10224.0
http://newlifegames.net/nlg/index.php?topic=13047.msg112336#msg112336
http://newlifegames.net/nlg/index.php?topic=16748.msg142004#msg142004

I think the condition you're seeing is known as a vertical collapse, I was searching for that
and found quite a bit of info on arcade forums. The type 58 monitor has limited information
available, I presume because the touch screen model was not as popular as the regular
non-touch edition. I think Merit Type 66 might be the equivalent.


I found a pic of a similar board on eBay. It *looks* like your board, and if it is, I think I see a
small green wire between two caps. Maybe this will help illustrate what needs to go where.

[mantaramian]

Thank you Merlin,

I am going to get the vertical transistor at my local Fry's or electronic surplus store here in Sacramento today.

I must say you did some great scouting for the monitor chassis. due to the Length of the wireless on my chassis, that makes perfect sense. it would have been easier if the factory would have left a little rosin behind. so I could have eliminated the research. lol

Once I get the horizontal transistor and the monitor fired up I will post my results.

Thanks,
Mike

[mantaramian]

Making progress, any suggestions to the roll? I have made adjustments to the chassis with no success.....

[firebird71]

If those 2 boards are the same it looks like the wire is soldered to C223

[cowboygames]

If your caps are good, check the resistors and diodes that feed you vertical output transistor

[mantaramian]

Thanks for the information, I am currently tracing down some of the diodes in the circuit....

Mike

[cowboygames]

You've got the schematic, try checking voltages on the transistor. Also, if it has a vertical adj pot, check to make sure it's working right. I'd bet you have a bad resistor or diode though

[mantaramian]

Just an update.... I'm sorry I haven't been able to post my progress lately... I Just bought a house and getting settled. I should have some progress over the weekend.....I didn't want the thread to be forgotten....

 

[mantaramian]

 So I have been plugging around the IC701 area, I have checked all the Resistor and Diodes in that area and all has check out on the meter. 
So I decided to lurk around the web for any technical information on this chassis but no luck other than few post about areas that get hot, there was mention that resistors may crack and would then be open. But, no such luck.
 
 What am I missing......? Am I in the wrong section?
Any constructive advice will be greatly respected….. Monitors are not one of my specialties…
 
Mike