20 October 2010

Does your FT-857 display look like a zebra?

I have come across several cases of malfunctioning display in the control head of the FT-857, where several "scan lines" in the dot-matrix display cease to function, so the display seems "streaked" at places. In extreme cases, the display becomes difficult to read. The funny thing is, the streaks come and go, or seem to move about the display with time! I finally got to open a control head belonging to a friend to see if there was something that could be done. The photo (click to enlarge) shows the display module ribbon, which is soldered directly to the PCB. The connections on the PCB turned out to be OK, so I checked the LCD side. I couldn't spot anything there either, but I saw that flexing the flexible ribbon near the LCD glass made some of the streaks come and go. The flexible ribbon is attached to the LCD glass with epoxy material. This reminded me of my experience with my Sony F-717 camera, where the epoxy material holding the CCD sensor on its carrier had softened due to heat and humidity, making the connections fail - the CCD had to be replaced. Perhaps the control head of the '857, when subjected for a long time to the temperature extremes and humidity inside a car, suffers a similar degradation of the epoxy material at the LCD display, eventually causing those streaks to appear. All of the affected units I know of were actually being used in cars! For the time being, I can't think of a solution, except of course replacing the whole display module - a bit tough.
So, my advice is, don't leave the control head(s) in your car exposed to the sun, humidity and temperature extremes, the dot-matrix display might become "streaky"! I, for one, have always covered the FT-857 control head in my car with a piece of black cloth, protecting it from strange eyes and the deleterious effects of sunlight. After five years in the car, it still operates fine.

I'll keep my fingers crossed - and my control head covered!