Adjusting KX-155 Display Brightness

stackj · #1 12-24-02, 09:15 AM

Sten,

Does the KX-155 manual indicate that there is a sensitivity adjustment for the photo cell which drives the display brightness? I have one that you can hardly see. If you point a flashlight toward it, it is plenty bright.

Sten · #2 12-24-02, 09:23 AM

Yes, there is a trim pot on the display circuit board that adjusts the dimmer level. Give me a day or two, and I'll try to scan the illustration of the layout and post on the board.
/Sten

stackj · #3 12-24-02, 09:30 AM

Thanks! That's great! It will make my wife very happy!

Of course, it will probably take two weeks of radio disassembly to get to it.

Pete Somers · #4 12-24-02, 05:40 PM

The dimmer pre-set should be marked on the outside cover, and is adjustable without removing the covers, but it only adjusts the max brightness.
More that likely the photo cell has got dirty causing the display to be dim all the time.
Try a new photocell, very easy to replace.

Pete Somers

Sten · #5 12-25-02, 11:41 AM

Here is a pic of the main PC board. The display intensity pot is R438. It's the one with the red arrow. Be sure to observe all regulations concerning avionics maintenance!!

stackj · #6 12-25-02, 11:07 PM

Thanks for the information, Sten. I promise to be a good boy, or at least have a good boy check behind me before returning it to service.

Sten · #7 12-26-02, 04:48 AM

Good Boy! :-)
Like Pete says above, it could be the photo cell that is bad or dirty. In our experience, when the display starts to loose it's brightnes, that's usually a sign that it's about to go south. It can be readjusted with the pot a couple of times, then is only visble when the radio has warmed up, then finito. The display is real easy to replace, just plug out - plug in, but a bit expensive at around $300.
/Sten