How I repair a PERX 17inch monitor.

This is the first time I come across this brand monitor.
The model is 17M121B
I believe it is made in CHINA.
There's no power indicator outside the panel.
When I applied power, I can hear a soft tic tic sound.
Opening up the cover, I noticed it has a samsung mother board attached inside.
The power supply ic is DP704c.
The horizontal output transistor is C4997
The voltage on the reservoir capacitor seems right at 318voltdc.
Found voltage at the secondary seems to be fluctuating.
Further checks shows that the horizontal output transistor shorted.
Replacing it seems to solve the problem.
Put it on soak test for a day and it seems working fine.
Sometimes we need to change only one component.
I will put up a link for component testings soon.
It will on my main website.

HP monitor model : 5500 with only yellow color.

Today we had this same model HP monitor with only yellow color.
So what happened to the rest of the colors?
Now since this HP monitor is the same model, I do not want to upload the pictures again.
So let's just do the troubleshooting here.
Now what is usual faults about this HP monitor?
Since it is already in use for a couple of years, there is difinately some dry solder joints,
weak cables or hardened data cables attached to this HP monitor.
My favourate would be to give a couple of slight knocks on the monitor itself.
Just as lucky as before, it is really caused by dry solder joints, but where?

So we began to strip down the monitor casing after removing a few screws.
For color problems, dry joints are usually occurred at the picture tube pcb board.
It is a small pcb board attached to the picture tube itself.
Looking closely, we notices that there are alot of dry solder joints around the pcb board.
Here, we did a round of resoldering to all the loose points/joints.
Before assembling back the monitor cover/casing, we applied a number of knocks on the pcb board to ensure there's no more dry solder joints.
So it's another easy job for us.

Do visit my website for more troubleshooting monitor repair tips.
I will post often.
Do enjoy your repair works and take special care when troubleshooting with supply on.

Before opening it's cover, we tested the press button switches at the front panel.

All buttons function perfectly except for the horizontal size.

With some slight knocks on the monitor, we noticed the display changes.

Display becomes perfect on and off.

This shows that there are dry joints on the solder boards.

Notice that there were some black patches on the board.

We then procede to resolder all the dry joints visible.

Further testing shows display perfect.

No pincushion anymore.

Button for horizontal size functions perfectly.

Display comes back normal.

Notice that there were some black patches on the board.

We then procede to resolder all the dry joints visible.

Further testing shows display perfect.

No pincushion anymore.

Button for horizontal size functions perfectly.

Display comes back normal.