Good day everyone.
I have this CRT monitor laying down in my warehouse so I am just try to fix it, after makes some effort to dig into CRT monitor troubleshooting knowledge, I am open it up , discharge tube and looking around mainboard and RGB board.
The symptom of monitor : no picture, no sound, not even led on power button lit.
After open it, found these :
1. Open Fuse
2. Fryed FET = MTP6N…. (can't see rest number ,cracked on right side) on primary PSU
3. Burned and changes color almost black, polyester caps = 842J 400VMpp right beside HOT
4. Shorted 1N4148 diode on primary PSU
5. High ESR value lytic 100uF 160V
6. Nothing else were look abnormal include good physic of flyback transformer.
What I have done because it just look like a PSU symptom but not to overlook :
1. Changes diode and fuse with same rating and number also buy new replacement.
2. Changes badcaps with Rubycon 220uF 160V.
3. Checks all component near fryed FET trace include 4 mains diode rectifier, others is okay.
4. Checks primary winding PSU transformer and near HOT (didn't know exactly function of this circuit) with flyback tester no problem.
5. Checks HOT and flyback B+ and Collector (primary winding) with flyback tester no problem.
I have buy FET with number code FQP6N60A because guess it was MTP6N60, couldn't find 824J 400V caps on my town.
So after this, I want to ask question from this amazing forum members.
a. Could I changes with this FQP6N60A FET?
b. Instead 824J caps, I have two 474J caps, is this okay if I am make it paralel to change this caps?
c. I have read about X-ray Radiation dangerous and haven't HV probe to measure the anode cup.
How to avoid and adjust this X-ray Radiation with decent tester?
d. Is there a problem changes badcaps with 220uF value (haven't experience on Monitor PSU)?
e. Is there any chance on this case the PTC has failed? It couldn't measured with VOM.
sorry for blurry picts from Android 2MP camera. any advice and suggest very appreciated please
I think so useless to laying down this girl in warehouse
I have this CRT monitor laying down in my warehouse so I am just try to fix it, after makes some effort to dig into CRT monitor troubleshooting knowledge, I am open it up , discharge tube and looking around mainboard and RGB board.
The symptom of monitor : no picture, no sound, not even led on power button lit.
After open it, found these :
1. Open Fuse
2. Fryed FET = MTP6N…. (can't see rest number ,cracked on right side) on primary PSU
3. Burned and changes color almost black, polyester caps = 842J 400VMpp right beside HOT
4. Shorted 1N4148 diode on primary PSU
5. High ESR value lytic 100uF 160V
6. Nothing else were look abnormal include good physic of flyback transformer.
What I have done because it just look like a PSU symptom but not to overlook :
1. Changes diode and fuse with same rating and number also buy new replacement.
2. Changes badcaps with Rubycon 220uF 160V.
3. Checks all component near fryed FET trace include 4 mains diode rectifier, others is okay.
4. Checks primary winding PSU transformer and near HOT (didn't know exactly function of this circuit) with flyback tester no problem.
5. Checks HOT and flyback B+ and Collector (primary winding) with flyback tester no problem.
I have buy FET with number code FQP6N60A because guess it was MTP6N60, couldn't find 824J 400V caps on my town.
So after this, I want to ask question from this amazing forum members.
a. Could I changes with this FQP6N60A FET?
b. Instead 824J caps, I have two 474J caps, is this okay if I am make it paralel to change this caps?
c. I have read about X-ray Radiation dangerous and haven't HV probe to measure the anode cup.
How to avoid and adjust this X-ray Radiation with decent tester?
d. Is there a problem changes badcaps with 220uF value (haven't experience on Monitor PSU)?
e. Is there any chance on this case the PTC has failed? It couldn't measured with VOM.
sorry for blurry picts from Android 2MP camera. any advice and suggest very appreciated please
I think so useless to laying down this girl in warehouse
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