Kortek KTN-2001 19"

claysred

Member
Joined
Dec 1, 2007
Messages
128
Reaction score
2
Location
Texas
I'm stumped on this one.
This one had a burned up diode at D605. I replaced it, and upon powering it up, it squealed like a pig. I replaced all the caps, and the HOT Q604. Powered it back up, and it blew the HOT again and squealed like a pig. I removed the flyback and powered it up and it was quite. So..replaced the flyback FN-1441B and the HOT again and now it powers up. I hear high voltage and static electricity in the tube. However, there is no picture, even when I turn the screen knob up on the flyback. Also, the neck does not glow orange, so I don't believe the heaters are working. I checked voltages on the back of the neckboard at CN501.

Pin 1: 11.5V, should be 12
Pin 2: 4.5 clamp
Pin 3: 2.0 contrast
Pin 4: 0.2...this is the heaters
Pin 5: -73.0V G1
Pin 6: 0V ground
Pin 7: blank
Pin 8: 138V, should be 180.


I checked R704 and R701. They are good. Not sure why the heaters don't have any voltage.

I can use any suggestions.

Clay
 
Ken......are you referring to IC301 which is a TDA 2595? Looks like it crosses to a NTE 7115.
 
No. After looking at the schematic, if you had D605 burnt up, then the flyback must have been shorted or one of the diodes connected to the flyback was shorted like D704 and D705.

D403, C412, C413, C414, and L401 provide power to D605. Possibly when that diode cooked it damaged one or more of those components.

In the power supply section, transistor FE401 is the main power transistor. Trimpot VR401 sets the B+ voltage.

Schematic:

http://www.casinotech.com/kortek/tech_docs/info_tech_docs/crt_schematics/KTN2001_Schematic.doc
 
Ken,

I checked the components you suggested. All check fine. However, I think the FE401 is bad. When doing a diode check on it, the center and left legs are both open. The center and right leg show open with the red lead on the center leg, and show 0.530 with the black lead on the center and red on the right. The left and right legs read open both ways.

FE401 has ssh6n80a on it. I believe this is a samsung chip. I'm having problems finding it. I think NTE 2377 is a cross. However, no one stocks it.

Clay
 
Pin 8: 138V, should be 180.
Clay

Pin 8 is straight B+, right? Where are you seeing it should be 180V? I have a working board that is putting out a nice 125, and a board that displays raster but nothing else that was first 180 and I can't get it to adjust down past 134 or so.

I just got a PDF of the service manual, and there is a decision block that says 'Check B+ 100V'.

The service manual says to check T101 and then D403, D404 and D401 if B+ isn't 100V

I am so confused by the varied info on this chassis.
 
On my schematic, connector CN702 shows pin 8 to be 180V. That's where I got the 180V.

I would love to have a copy of the service manual.

Clay
 
I replaced F401. Monitor status did not change. I hear the high voltage, but don't get any raster or neck glow from the heaters. B+ voltage is 142.

I'll take any suggestions.
 
Back
Top Bottom