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KY 97A - PWM dimmer?

blaplante

Well Known Member
This may be way too deep, but I'll throw it out for someone... Looking at swapping an older King 197 Comm for a free KY 97A (known good too).

Looking at the pin out differences...

Looks like the old radio had a built in dim sensor, while the KY 97A has pin A "Dim Select" and pin B for +14 V lighting input. So, OK, cool it can track panel dimmer lighting. However... I don't have a simple rheostat, I have a PWM dimmer circuit. [Buzzword alert: PWM = pulse width modulation, basically the dimmer dims by turning on and off many times per second, varying the on vs. off time to control brightness.] Similar to https://www.aircraftspruce.com/catalog/elpages/pwmdimmer.php - but actually home built. Has anyone used a PWM dimmer with a KY 97A?

I'd hate to put this in and discover I can't get the dimming to work.

thanks in advance for helpful info.

-Bryan
 
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A simple RC circuit can change the PWM to average DC. E.g., line from PWM to resistor to capacitor (other side to ground) and King dimmer input.
 
A simple RC circuit can change the PWM to average DC. E.g., line from PWM to resistor to capacitor (other side to ground) and King dimmer input.

Yes, but the KY 97A is pre-LED so the incandescent bulb should act the same as the RC circuit shouldn't it?
 
Yes, but the KY 97A is pre-LED so the incandescent bulb should act the same as the RC circuit shouldn't it?

If the dimmer circuit directly drives the bulb, yes. If there?s some circuit in between, can?t say. Shouldn?t hurt to just try.
 
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