Kortek Blacking Out

[firebird71]

I have a Kortek 1703 monitor that blacks out after about 20 min. When the monitor blacks out, it kills the cap# c121, and c408, it also takes out the H.O.T. Another thing that may be important is that the heat sink for the H.O.T. is very hot when it blacks out. If I replace the caps, it will come back on but will only last for about 20 min. Any help would be appreciated.

[cowboygames]

What voltage reading are you getting on the collector leg of the HOT when it's running? Should be 130v. I would suspect a faulty voltage regulator transistor or leaky diode first

[firebird71]

Okay I put the negative lead of the multimeter on the base, and the positive lead of the meter to the collector but I am not getting any readings. I have the meter set to 200vdc, but am getting nothing. I am new to this and hope I connected it right. I did unplug the monitor before it failed so it should fire back up for another test.

[cowboygames]

Just go centrr leg to ground. With the unit running, should be around 130v

[firebird71]

OK, now I am confused, I connected to center leg and grounded to the chassis, I still get no reading, but the monitor is running. I have checked for both AC and DC voltages, but nothing.

[cowboygames]

Me too, there has to be voltage there to get horizontal drive

[JustTech]

Your power supply is running off with voltage if you check your voltage on C121 you will find it high should be around 65 volts according to the schematic try to see if replacing c107 and c108 in primary circuit will bring your voltage back down.


JustTech