The iRiver AFT100 FM modulator is a very nice product. But one annoying feature is the auto-off after 30 seconds of no audio. The time period is too short and it is fooled by quiet music. So I decided to try to disable it.
Searching the internet turned up many people unhappy with this feature but no instructions on how to disable it (just one review where the reviewer said he figured out how to disable it on his). So I got out my scope, 12V power supply and figured it out myself.
Warning: do not attempt this modification unless you are comfortable opening small electronics and soldering to surface mount components. I won't be held responsible for any loss or damage if you attempt this modification.
That point in the circuit is at ground while music is playing but starts to charge up when the music stops. When it gets high enough the modulator shuts off after a bit. This mod holds that point at ground whether or not music is playing.
- Opening the case: unscrew the tip being careful not to lose the spring, fuse or tip.
- Separate the two halves of the case starting from the tip end. Work your fingernails down the sides.
- At the start of the wide part of the body there is a clip on each side. Press in on the bottom plastic and out on the top plastic and the top should come unclipped.
- You will need a fine-tipped temperature-controlled soldering iron, electronics solder (Do not use acid-core solder!), and a short fine wire (wire-wrap wire or one strand from a multi-strand wire).
- Locate Q2: looking at the top of the PCB, with the tip on the left and the display on the right, Q2 is located right where the circuit board widens out, a little bit above center.
- Tin the top left pin (nearest the Q in Q2) with a small amount of solder. Be careful not to bridge to any other pads or components.
- Solder one end of the wire to this pad.
- Bend the wire in an arc and solder the other end of the wire into the large hole labeled V- (just below Q2). Do not stick the wire too far through the hole or it may bend over and touch other components.
- That's it. Visually check for shorts and if it all looks good snap the top back on (making sure the cable is in the right place). Screw on the tip and give it a whirl.
If your cigarette lighter plug doesn't turn off with your key remember to unplug the modulator or you may run your battery dead.
If you are not comfortable with opening and modifying your modulator contact me and I may be able to help you.
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