    
Shakymcquiver
New member
Username: Shakymcquiver
Post Number: 6
Registered: 4-2018
| | Posted on Wednesday, April 18, 2018 - 5:07 am: | 
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So I'm bored and dug out some of my old CB gear to tinker with as Winter in my area can't seem to figure out it supposed to be SPRING...?
Anyhow... I was successful at fixing a PC68LTW, so I thought I might move on to something else. I found an old echo mike in my parts box that doesn't power up. The outside of the mike says "Road noise" and "DM-313P". The board inside says "CB 660".
It's a fairly simple board inside, except for the SMT stuff on a couple of the vertical boards sticking out of the main board. Any of these mikes I've ever seen always had a red led that lit up when you keyed and spoke into it. The LED on this mike does not light, nor does it talk, so I suspect some kind of power issue along the way. I tested the LED separately, so I know it's good.
As well, there is no power present at the LED when the mike is keyed. The only power I've found past the battery is approx. .25 volts that goes into one of the IC's.
The mike will key my radio, but that's the mechanical switch doing that obviously. It just doesn't power-on and work.
The echo slider (variable resistor) is pretty greasy inside, but I don't know if that's enough to short things out. Those things are a bear to clean sometimes. I don't know if that slider passes voltage through it or not.
Most of those mikes look like they're made by the same (Taiwan) place, but they've slapped a bunch of different names on them, so finding information and a schematic has been an impossible task so far. So I'm hoping there's a guru on here that might have more knowledge on them?
Or forget about it and toss it back in the parts bin? I know you can buy these things dirt cheap nowadays and proly not worth messing with, but what the hell... it's still too cold outside to take the boat out of winter lay-up, so I have to keep the mind active in other ways...
Thanks again! |
