HP L1506 (BENQ 4H.L1T02 board) problem

[redmike5]

Hello everyone,
This is my first post in the forum so please be gentle.

I recently got from a friend a fried HP L1506 monitor. This monitor uses BENQ 4H.L1T02.A00 board and from what I could gather from the net, the board is same as in BENQ FP51G monitor.

So, when trying to power it up, the monitors LED would only flash orange and the monitor would show no signs of life otherwise.

I have opened the monitor and inspected the board. The two 1000uF/16V caps in the right upper corner were bulged so I am going to replace them.
The bigger problem I have is with the big 68uF/450V cap in the centre. The were signs of electrolyte leakage around one of the leads and when I moved the cap to read its specs that lead broke, just like it was badly corroded.

Now I have spare 1000uF/16V caps so no problem here, however the 68uF/450V one is more of a problem, since I haven't got any. I have a 100uF/450V and two 68uF/400V though.

So the real question is: can I replace the original 68uF/450V cap with any of the above ones. Or combination of the two 68uF/400V? Even as a temporary fix to see if this cures the problem, or a more extensive damage is present.
I know that this may be a silly question, but I hope somebody can answer it.

PS. The picture attached it from internet and taken by me, but this is exactly the same board.

[PlainBill]

Re: HP L1506 (BENQ 4H.L1T02 board) problem

Hello everyone,
This is my first post in the forum so please be gentle.

I recently got from a friend a fried HP L1506 monitor. This monitor uses BENQ 4H.L1T02.A00 board and from what I could gather from the net, the board is same as in BENQ FP51G monitor.

So, when trying to power it up, the monitors LED would only flash orange and the monitor would show no signs of life otherwise.

I have opened the monitor and inspected the board. The two 1000uF/16V caps in the right upper corner were bulged so I am going to replace them.
The bigger problem I have is with the big 68uF/450V cap in the centre. The were signs of electrolyte leakage around one of the leads and when I moved the cap to read its specs that lead broke, just like it was badly corroded.

Now I have spare 1000uF/16V caps so no problem here, however the 68uF/450V one is more of a problem, since I haven't got any. I have a 100uF/450V and two 68uF/400V though.

So the real question is: can I replace the original 68uF/450V cap with any of the above ones. Or combination of the two 68uF/400V? Even as a temporary fix to see if this cures the problem, or a more extensive damage is present.
I know that this may be a silly question, but I hope somebody can answer it.

PS. The picture attached it from internet and taken by me, but this is exactly the same board.

This is one of those times when it may be acceptable to use a lower voltage cap. What is the line voltage in your area? If your nominal line voltage is less than 250 volts you should be able to use the 68uF, 400 volt cap. You can use the 100uF, 450 volt if it fits.

PlainBill

[redmike5]

Re: HP L1506 (BENQ 4H.L1T02 board) problem

Thanks PlainBill. I really appreciate your reply.

I live in the UK and the nominal voltage in 230V +/-10%, so in the worst case scanario 253V is possible, but probably not very likely.

Anyway, I am going to try the 100uF 450V at least in the interim, to see if I can get the monitor going.

I will report on the progress in due course.

[PlainBill]

Re: HP L1506 (BENQ 4H.L1T02 board) problem

Thanks PlainBill. I really appreciate your reply.

I live in the UK and the nominal voltage in 230V +/-10%, so in the worst case scanario 253V is possible, but probably not very likely.

Anyway, I am going to try the 100uF 450V at least in the interim, to see if I can get the monitor going.

I will report on the progress in due course.

That sounds like a good idea. IIRC, a cap is spec'd for something like a 20% overvoltage, and I was allowing a 50V safety margin, but a cap exploding inside a monitor makes a real mess.

PlainBill

[redmike5]

Re: HP L1506 (BENQ 4H.L1T02 board) problem

I finally managed to get back to this monitor.
I have replaced the two 100uF 16V caps and the primary 68uF 450V.
Also resoldered the whole secondary side of the inverter.

The monitor started just fine in self-test mode and works fine now.

Thanks for advice and hope someone else can benefit from the info.

Cheers, Redmike