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Help identifying this monitor - Kortek
infrared:
Thank you Ken and a happy new year.
infrared:
Because i need the schematics to help me repair my board (KT510A) and to do that i must look into 3 different documents i finally created the layout and the logic diagram from scratch.
I think that this layout-logic diagram will probably help also the owners of Kortek 1420A, Tekbit or Imperial
Please keep in mind that this creation is based to my board it is a first beta version and perhaps has errors.
I have check every connection and every type of component to prevent errors.
If an error has found please post it so i can repair the document.
Board Layout: http://www.firepower.gr/downloads/Kortek%20KT-510A%20Layout.pdf
Logic Diagram: http://www.firepower.gr/downloads/Kortek%20KT-510A%20Logic%20Diagram.pdf
Regards
Michael
Ken Layton:
--- Quote from: infrared on December 29, 2017, 01:33:51 pm ---Finally I changed transistors Q201, Q202 and monitor now works fine.
--- End quote ---
The vertical output transistors are mounted to the flyback cage. Many times when one transistor goes bad, it affects the other one too. So if you suspect a bad vertical output transistor, replace them both at the same time. Here is a picture of them.
Ken Layton:
--- Quote from: infrared on December 06, 2017, 03:36:08 am ---Hello to all,
please i need help to identifying my arcades cabin monitor. Monitor is 19" and i have sparking problem in the high voltage where the yellow circle is in the picture.
The only thing the board has is the mark Kortek but no model
Any help appreciated
Regards
Michael
--- End quote ---
Updating this thread. He has the Kortek KT-510A also known as Penn-Ray model 17-0214 (13" version) and 17-0220 (19" version). This model has two large aluminum heat sinks attached to the sides of the chassis. The heat sink on the left is the B+ regulator (2SC1629A transistor or 2N3055 transistor bolted to it). The heat sink on the right is the horizontal output transistor (2SD900B bolted to it).
Ken Layton:
One problem this model (KT-510A) and the KT-1420A have is with the high voltage shutdown circuit keeping the monitor from powering up. If you have recapped it and that didn't get it powered up, there are two other items to check:
1. The high voltage shutdown pot (R415, labeled as "X-Ray" on the board). Sometimes the glue used to seal the pot makes the pot go bad internally. It's a 5k trimpot and here is where you can get it:
https://www.arcadepartsandrepair.com/store/monitors/5k-ohm-trimmer-potentiometer-p1014/
2. The zener diode D401 (located directly to the left of the integrated circuit) may have gone "leaky". Unsolder and lift one end of it and re-power the monitor. Does it power up now? If so, check that diode out of the circuit for an electrical leaky condition. The manual and schematic call out this diode as type 05Z12Y which in reality is a 12 volt @ one watt zener diode. You can use a type 1N4742A or an NTE142A diode to replace it.