Spotty Panel Display On 4000tn

[Homey]

I recently bought a used HP 4000TN, page count: 137570 (formatter number S4601Z166RK); date of manufacture: Dec 1997. Everything works fine except the display panel letters are very faint, especially when the message displayed is "Ready". After pulling the top cover, it appears the printer was used in a smoke-filled environment.

As I go thru the various menus, some pixels light up normally, others don't. When the printer is first turned on the two lines of ******s all appear normal (proper contrast and nice dark pixels). However, on some displayed messages the left side of the message is light and the right end of the message is normal. However, as I go thru the menus, this condition doesn't remain constant. It seems that some pixels that don't light up normally in one menu do just fine when I get to another menu.

What could be causing this and what can I do about it?

Thanks for any help you can give.

[redcow]

I suppose if you have another 4000 you could swap control panels. I think it gets its voltage from the engine control board.

The control panel is cheaper and easier to change.

[Homey]

Thanks, Redcow:

I did have another 4000 and swapped out the control panel. The problem is with the one bad control panel (the bad display was exactly the same on the other printer; the good display worked perfectly on both printers). I have a local HP store that will sell me a refurbished control panel for $29. Problem solved.

thanks
Homey