[PTSchram]

First off, sorry for the cross post with Discoweb, but I'd bet most of us here know how to solder.

The blower switch on my Disco is slowly dying. I will not pay more than $100 for an entire assembly when I really only need a $2.00 slide switch.

As this is a fairly common failure mode, has anyone found a domestic replacement? I went through the picture book at Advance last night and struck out. The circuit is simple, but the mechanics of building a switch are not. I can wire it several ways, using a number of different switch configurations, some better than others. Right now, I'm leaning toward a rotary switch, either retaining all of the functionality of the original, or just having two or three speeds.

Anybody got any suggestions?

Peace,
Paul

 

[Discosaurus]

I've never actually seen the workings of the slider but, knowing how it feels every time I use mine, I'm just waiting for it to crap out. Actually, it's felt that way since new.

How about replacing it with a bone yard unit ?

If that's not an option, probably the easiest replacement is with a multi-contact rotary switch, like you said. I didn't look at the LR schematic but, in the "old days", it was just a multi-tap voltage divider that controlled motor speed - a switch, a hand full of resistors and you're done.

'Course, in the 21st century, speed is probably controlled with a bank of microprocessors....

keith
:usa:

 

[PTSchram]

I would go with a boneyard switch if it weren't for the fact that these switches fail at about 60-70K miles and there is little use of going down the same road again, if oyu know it is still paved and there are no new buildings on it.

The diffiuclty of the circuit is that in position one, the relay is hot, and there is no current to the resistor bank. In position two, the relay is hot, as is resistor bank position number one, in position three, the relay is still hot as is resistor bank number two, in position four, the relay is hot, as is resistor bank position number three. I'm thinking I can use a single wafer rotary switch with a diode so that when the switch is in position one (slowest speed), the relay can be hot in every position, yet not also electrify the others when you only want the fan on slow speed.

If I wasn't a pencil kinda draftsperson, I could make a pretty picture that would graphically illustrate this.

I'm really surprised that with thenumber of Disoc drivers there are around here and elsewhere that nobody has tried to solve this problem...

Peace,
Paul