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euro-pro llc
euro-pro llc, Technician
Category: TV
Satisfied Customers: 1636
Experience:  20 years in TV repair,certified by all major brands- Sony,Samsung, LG,Toshiba, Panasonic, RCA,
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Toshiba model 42hp66 Plasma flat screen Problem No picture

This answer was rated:

Toshiba model 42hp66 Plasma flat screen


No picture or sound.
Pushing on button 2 clicks are heard

A slight hum is heard at the Z SUS board.

Green power light is on (power light is red when unit is off)

Slight clicking sound from Y SUS board. Now that I replaced the open Fuse.
(Fuse 4AH250VP Found open on Y SUS board as looking at rear the Fuse on the left).

Still no operation?

Hi, I will try to help you with this question.

You CANNOT replace only the fuse on the Y sustain board!!!!

By having a blown fuse on the Y sustain board, you will have a overload/ short on the VS line!!

If you replace only the fuse, you may create more problems !!Now, how many fuses are on the Y sustain(one or two)?

I am interested on the big glass or ceramic fuse.

Thank you.

Customer: replied 5 years ago.



Then what is the problem?


We knew replacing the fuse did not fix the TV.


The fuse found open was on the left of 2 that are side by side in plain veiw

No Not Large it is labled 4AH250VP


But i wrote this in the first note?


Customer: replied 5 years ago.


The fuse in Question is on the Y SUS Board


Just in case that is not clear?



I understand this, but some versions have two fuses on the Y sustain board, one providing the Vs for the Y sus, and the other providing the Vs for the Z board(in this case you will have a cable that routes this VS from Y sus to Z sus.

Most of the time the Vs is supplied separate from power supply to Y sus and Z sus

If the fuse on the Vs for Y sus is open =defective Y susboard-NO DOUBT about this!!

The Y sus will need to be replaced!

Tv cannot be repaired by replacing the fuse only!

Will you be able to check some voltages for me inside this set?

Customer: replied 5 years ago.



Yes there Are 2 fues on the Y SUS it was the one on the left as you look at the back side of the set.


Ok What voltages and where ?





Please check the voltages on both sides of the fuse that was open(and now is replaced).

Then also check the voltage on the other fuse(that was not open)You need to have the tv on and running, and use the meter on DC voltage(black lead on chassis ground)

Thank you

Customer: replied 5 years ago.


Fuse that was open but now is replaced (on left of the pair of fuses on Y SUS board):


= 187 V DC on both sides of fuse.


Fuse next to it ( right side of the pair)

= 60 V DC



Customer: replied 5 years ago.

Just noticed the Z-SUS large black Heat sink is slightly warm to the touch.

And the Y-SUS large black Heat sink is cold to touch.


Does that help?

The Y sus heat sink is cold because this board is not working.

The 187 and 60V are all right, this tells me that the Y sus was shorted (this was the reason for having the fuse open) but when you replaced the fuse- the new fuse did not open up anymore, but something else on the board opened up, removing the short on the VS line.

The Y sustain board is defective and it will need to be replaced.

The part# XXXXX this Y sus board is:


The best price I could find for you for it is here:

This is a very common issue with these sets, and most of the time is the only failure inside the set.

I believe that replacing this Y sus board will fix your problem.

Please note:

The Y buffer can also be defective, but because this open fuse on VS that you had is unlikely..

Please accept my answer if you are satisfied and will be able to leave a positive feedback.

Thank you, XXXXX XXXXX a great day!

euro-pro llc and 2 other TV Specialists are ready to help you

Please feel free to ask any additional questions, I will gladly help you.

Thank you