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Dash mount spectra backlight problem
Posted: Thu Apr 29, 2004 8:03 pm
by Rick Rock
I just got in a spectra that the backlight isn't working. I enabled everything in rss and still nothing. Just to see if it was the head, I put another radio head on it, and it lit up no problem. Is there a fuse on the head somewhere??? When you hit the DIM button, the display will dim like it's supposed to, just no button lights.
Posted: Fri Apr 30, 2004 10:44 pm
by williamh
i have the same problem with mine .... looked real close and couldnt find any blown fuse or broken foil trace ..lookes like it goes threw a chip ... and thats where i lost it ... no manual to figure out where the power comes in from... would like to know myself ... i would just jumper it out and have them on all the time ...
good luck ...
Posted: Sat May 01, 2004 6:46 am
by Mike B
You never said which control head you were using, so I will just assume it was an A5 or A7 type head.
The newer control head circuit boards have jumpers to override the backlight control. Jumper JU16 is installed and JU17 is not installed for normal operation. To always force the backlight on, jumper JU17 is installed and JU16 is removed. If both JU16 and JU17 are removed, then the backlighting will not work at all.
There is also a jumper JU100 that will only disable the keypad backlighting when it is installed. This jumper is also on the older circuit boards.
All of the backlight LEDs are controlled by transistor Q131. If it burns out, no backlights will work. The backlight LEDs are all in series, so if one burns out they all go out.
If the RSS selects an "enhanced" control head, it can be programmed so none of the backlighting will work. If you plug in an older head that is not "enhanced" compatible, it will ignore the software and the backlight will work anyway. If you plug in a newer "enhanced" compatible head the backlighting will be whatever is programmed in the RSS control head screen.
Your backlight problem could be a hardware failure, jumper settings or RSS programming related. There are quite a lot of different circuit board part numbers for these control heads.
http://www.open.org/~blenderm/spectra/#combo
Backlight?
Posted: Mon May 03, 2004 6:55 am
by Rick Rock
Sorry I thought I'd posted the head- It's an older A-5 head #HLN6075D. As for Mike B's link- I don't see a link or anything to show where the jumpers are(?). If someone knows of a link to show where the above mentioned jumpers are, that would give me a good place to start!