Kortek Monitors Tips,Tricks and Cap Kits

[Kyrosfear]

This thread is going to be a god-send for me shortly.

I recently picked up several Kortek monitors with various issues. Excellent, thank you gentlemen.
-Kyrosfear

 

[midcoastsurf]

Just got done reading through the five pages of notes...my head is spinning. I have a Kortek 2914 with a 2182 chassis. The chassis no longer turns on and I do not get any voltages at the large diodes in the power supply section (D120 and D121). I do measure voltage at either side of the fuse clips with the other lead on ground. The fuse is also good.

I replaced the HOT, the large resistor at R118, and a handful of caps.

What next? The manual said to check F801, D801, IC811, and IC812. I don't even see F801 (there is only the F101 fuse), nor do I see the two IC's mentioned.

Thanks

 

[Ohmerone]

Just got done reading through the five pages of notes...my head is spinning. I have a Kortek 2914 with a 2182 chassis. The chassis no longer turns on and I do not get any voltages at the large diodes in the power supply section (D120 and D121). I do measure voltage at either side of the fuse clips with the other lead on ground. The fuse is also good.

I replaced the HOT, the large resistor at R118, and a handful of caps.

What next? The manual said to check F801, D801, IC811, and IC812. I don't even see F801 (there is only the F101 fuse), nor do I see the two IC's mentioned.

Thanks

You still working on this chassis I seen some of you pass notes
from another site..

Is the Kt-2182 the same as the Kt-2914 so I can check the schematic?

You might take a picture over top of chassis so We can look at it good

For any obvious bad parts and can point you to suspects

Or send a PM for more details, or send it out for repair.
there shouldn't be any 800's in the power supply circuit.
Was R118 open?
Does the power supply heat sink ever get hot?
after a few minutes, unplug the chassis and check to see if its warm at all.
Are you switching your ground lead to Hot ground when on the Hot side
of SMPS and cold ground when on cold chassis side?
If not you dc measurements will be wrong during testing.

 

[Ohmerone]

Mine did this. It was a blown 19n20 MOSFET. It was the inside one that is attached to the heat sink but apparently there all known to go. I've still yet to finish fixing my chassis so it could be something else but I'd take a look at them.

Need to check the other resolutions to see if they work..

on all tri res chassis some could work on Vga and not on medium res or

standard res in most case's the standard is the default res so without

a signal it should go to standard res and display a colorbar pattern

or No signal message.

The game maybe using Med res and your not checking the others

test them too. It helps to know if anything is working correctly!!

Did you replace the switch drive transistor along with the correct mosfet??

The chassis wont work right if two or more scan circuits are switched on.

I would not suspect the Micro most failures are High current Parts..

check the Frequency table on schematic for more details on which mosfet

should be turned on at which frequency.

Any more details about the voltages you notice?

 

[midcoastsurf]

You still working on this chassis I seen some of you pass notes
from another site..

Is the Kt-2182 the same as the Kt-2914 so I can check the schematic?

You might take a picture over top of chassis so We can look at it good

For any obvious bad parts and can point you to suspects

Or send a PM for more details, or send it out for repair.
there shouldn't be any 800's in the power supply circuit.
Was R118 open?
Does the power supply heat sink ever get hot?
after a few minutes, unplug the chassis and check to see if its warm at all.
Are you switching your ground lead to Hot ground when on the Hot side
of SMPS and cold ground when on cold chassis side?
If not you dc measurements will be wrong during testing.

Here are some more pictures. The sticker on the frame says Pro Vision KT-2938 and the chassis is stamped KT-2182. I noticed that TH102 is black and there are burn marks on the nearby heatsink (last picture - directly below the large brown cap). I measured across the two legs with my DMM set to resistance and I get 005 (it starts at 400 and drops down to 005). I currently do not have any DC voltages coming off the power supply diodes (D107, D110, D120, D121). I was not getting heater voltage and R118 was only measuring 0.3 with one leg removed from the board. It is a 1.3 ohm resistor.

"Are you switching your ground lead to Hot ground when on the Hot side of SMPS and cold ground when on cold chassis side?" How do I know which side is which? Are the large diodes on the hot side? Where is hot ground? I assume cold ground would be the metal frame around the tube?

Thank you for your patience and help!

 

[midcoastsurf]

Here is another picture w/ notes...

 

[Ohmerone]

Here is another picture w/ notes...

Heres from the PM

Originally Posted by Ohmerone
Does the heat sink get warm?

what's the number on the Ic in the power supply?


plug it in and measure the ac and the dc on the bridge Diode?

seen on pic#5

the big filter cap ground is the hot chassis ground.

it should have about 160v dc on the filter at all times.

the cold is the on the other side of the switch mode power supply

on any of the ground traces and its common to connect to the frame

of monitor or dag/ground wire around the tube, just to make sure

your reading the voltages correctly and using the correct ground.

Its not the 4 pin ic!!
Th102 is ok

Yes that's the heatsink..

I'm talking about the Ic on that heatsink.

It needs to have about 160v dc on one of the pins of that
Ic...its the PWM Ic for the primary.
If its cold odds are its not working.

yes that's the bridge rectifier..

 

[midcoastsurf]

The IC mounted to the heatsink is a 5S1265.

Viewed from the front from Left to Right:

Drain, Ground, Vcc, Feedback, Sync


I'll hook everything back up and start measuring voltages.

 

[midcoastsurf]

- The heatsink does not get warm (even after 5 minutes)
- IC on the heatsink does not get warm
- highest voltage at the IC measures 78.6vDC (other lead on cold ground)

- Bridge diode from left to right (ground lead was on cold ground), measures:

(+) = 78.6vDC
(AC) = 124 vAC
(AC) = 0 vAC (is this normal? I used the + lead on this, but didn't think it mattered)
(-) = 79vDC

Should the ground lead be on Hot ground when measuring a bridge diode? If so, I didn't see an area to clip my ground lead to (where exactly is "big filter cap ground"?)

I didn't see an area to measure 160vDC at the big filter cap.

Hopefully this helps. It seems like I am getting exactly half the DC voltage I should be getting.

 

[Ohmerone]

- The heatsink does not get warm (even after 5 minutes)
- IC on the heatsink does not get warm
- highest voltage at the IC measures 78.6vDC (other lead on cold ground)

- Bridge diode from left to right (ground lead was on cold ground), measures:

(+) = 78.6vDC
(AC) = 124 vAC
(AC) = 0 vAC (is this normal? I used the + lead on this, but didn't think it mattered)
(-) = 79vDC

Should the ground lead be on Hot ground when measuring a bridge diode? If so, I didn't see an area to clip my ground lead to (where exactly is "big filter cap ground"?)

I didn't see an area to measure 160vDC at the big filter cap.

Hopefully this helps. It seems like I am getting exactly half the DC voltage I should be getting.

You need to replace all the Electrolytic's in the Primary first!

I see some the original caps are still in the chassis.
All the caps should have been replace the first time.
After you do that then the Ic would be a suspect! if it is still dead.

 

[midcoastsurf]

Does the large 330uf 400v need to be replaced as well?

 

[cadillacman]

well well well i picked up another kortek 2914 this weekend...


Much to my suprise, this one works... but i have pincushion in at the center a little even if it is maxed out, and i have some retrace lines showing at the top 2-3" of the pic It also seems a touch jittery/shakey as well

I suppose i need to cap it and see what i get?

In the meantime, at least i have a known good tube and yoke to test all my other chassis with

 

[cadillacman]

SUCCESS!!!

I have three chassis with signs of life now..

Chassis that came with this monitor is really jittery.....needs caps and ?

Using one of my previous repaired chassis i have a decent pic, but had no green.

I swapped neckboards, then i had green but my osd was messed up. As in, all letters were messed up, looked like some ailen language.

I robbed the eprom from the same chassis i pulled the neckboard from... The eproms were different versions. That fixed the issue. Apparently theres more than one neckboard or software/hardware on the neckboard so your neckboard and chassis eprom must match

I FINALLY HAVE A WORKING KORTEK MONITOR!! WHoohoo!!

I still see retrace lines no matter which chassis i use, i think this is an issue with my laptop and not the monitor itself.

 

[Ohmerone]

SUCCESS!!!

I have three chassis with signs of life now..

Chassis that came with this monitor is really jittery.....needs caps and ?

Using one of my previous repaired chassis i have a decent pic, but had no green.

I swapped neckboards, then i had green but my osd was messed up. As in, all letters were messed up, looked like some ailen language.

I robbed the eprom from the same chassis i pulled the neckboard from... The eproms were different versions. That fixed the issue. Apparently theres more than one neckboard or software/hardware on the neckboard so your neckboard and chassis eprom must match

I FINALLY HAVE A WORKING KORTEK MONITOR!! WHoohoo!!

I still see retrace lines no matter which chassis i use, i think this is an issue with my laptop and not the monitor itself.

Sounds like all you need is some caps and maybe some advance adjustment

I would use the working chassis to test questionable parts in the other chassis
Replace those BP caps on the neck board they open up and then your missing a
primary color I just replace all three, found on most neck boards. C801 RGB
Im not sure if they come in the cap kit.

 

[Ohmerone]

Does the large 330uf 400v need to be replaced as well?

This is the reply I got fro MCS

I finished replaced a few caps near the bridge diode and one near R118. I also replaced the large filter cap. The monitor is back up and working. I will keep it on for the rest of the day to test it out. Hopefully the re-setting issue has also disappeared. The monitor would turn off and back on during gameplay.

Thanks


Incase anyone was wondering what the fix was..

 

[cadillacman]

Sounds like all you need is some caps and maybe some advance adjustment

I would use the working chassis to test questionable parts in the other chassis
Replace those BP caps on the neck board they open up and then your missing a
primary color I just replace all three, found on most neck boards. C801 RGB
Im not sure if they come in the cap kit.

Hey dumb question.. According to the manual theres alot more adjustments in "factory mode" but the manual does not tall you how to "set factory mode"

wtf? what am i missing here?

 

[Ohmerone]

Odds are from the other chassis the eprom may have different data values

so you may have to readjust these for best picture after you replace the caps

Press and hold down the UP button for 2 seconds at the same time plugin the chassis

let go and then press menu if nothing press menu again.

Need a signal on the chassis when using the OSD feature.

It should prompt to save when your done..

 

[alejandromad]

SUCCESS!!!

I have three chassis with signs of life now..

I FINALLY HAVE A WORKING KORTEK MONITOR!! WHoohoo!!

I commend your persistence!!!!

 

[cadillacman]

its too valuable of a monitor not to at least give it the old college try.

 

[geetee]

I have a KT-2914DF which worked before I took my cabinet apart 7 or 8 months ago. I finally got it all back together and now I'm not getting any picture. The screen is completely dark. Not terribly surprised because it took a fair amount of elbow grease to get the monitor out (the original owner literally wedged it in without screws or even the top cross brace).

I can see the faintest orange light in the neck, but I have no experience with what it should look like. The control board LED does not light up. I don't notice any buzzing or clicking sounds.

After spending so long without use, could it take some time to power up? In case it matters, it probably did not get colder than 40F while in storage.

My plan for now is to visually inspect for damage and reseat the plugs and neckboard. After that I am up for replacing the caps and other components. I have a healthy fear of zapping myself, so there is a fair amount of additional research ahead of me before I touch too many things.

Any advice or recommendations or does this plan sound solid? Thanks!