crazy remote control: candle

[SharpyWarpy]

Hi, everybody. I've got a Fisher amp that if I put a candle in front of the infra red sensor the remote works fine but without it remote operation is eratic. Is this the fault of the sensor or the microcontroller? I can scan part of the schematic if needed, it's a Fisher "Studio Standard" model CA885. Thanks.

[Limhes]

Could be that the remote is almost empty, transmitting less power than normal. The candle will then bias the signal to a somewhat higher level, so the nett levels for zeros and ones lie below and above the detector's threshold level.

Ergo, new cells?

[I_Forgot]

I am more interested in how you discovered that a candle fixes the problem that in the problem itself. You are a mutant!

I_F

[SharpyWarpy]

Originally posted by I_Forgot
I am more interested in how you discovered that a candle fixes the problem that in the problem itself. You are a mutant!

I_F

LOL, thanks I_Forgot. Actually, I got to thinking -- which is dangerous for a mutant -- it's infra red so maybe some heat will make a difference. So I lit a small scented candle, the kind in a tin, and put it about 6 inches in front of the sensor. It worked, even after I blew the candle out there was enough heat in the tin to keep it working until I moved the candle away. Moving it back got it working again until the tin cooled down.
I have changed the batteries twice, the last time with good tested batteries which work in another remote. I really don't think it's the handheld controller because I've taken it apart and cleaned it up, seems like it wouldn't work at all if it were bad, especially since the problem manifests itself after the amp has been on for about 20 minutes.
I should mention here the amp was the victim of a line surge when it belonged to the previous owner, she didn't want to fool with it when it quit working and she gave it to me. A zener diode was bad, which I replaced with one I had on hand and that got it to power up and work, which tickled me to death. But I'm wondering now if the same line surge might have fried the remote microprocessor, too.