Alternative Dual Scanner Power Supply

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digitalanalog

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eBay a while back, just remembered why I bought it.

Powering to scanners and a modified powered speaker
off a $10.00 Model Train Controller.
Details of the build to follow shortly.

Here is what I am starting with.
 
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SCPD

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Some model RR regulators use a pulsed waveform - variable pulse width at 40 to 60 Hz. I don't know if this one is smooth DC or pulsed.
 

digitalanalog

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It is a 60Hz pulse.

I tested this the other day and had 2 BC-350A scanners hooked up to it, the output was 10.6 volts to each radio, plenty to run the 2 radio's, while allot of radio's wall adapters(wall warts) have an output of 12V i have tested many scanners with a 13.8 volt output(standard car battery is 13.8 volts at PEAK charge and not 12V as some seem to think), and using a DC analog 15v meter inline with a rheostat i am able to cut the voltage clear back to 8 volts and the only thing noticeable is the back light is much dimmer, and yet the scanner still receives a full signal (weather channels are the best to use for this type of testing), I also tested the same way by turning the train power supply knob and the same thing was true, i could run 2 scanners down to about 8 volts.

So while keeping this in mind, I now have a use for all the 9V wall warts that I gathered through out the years, they will IN DEED work for any scanner providing the plug end is correct.

The two scanner/train power supply idea was merely another test, the outcome is the train power supply causes a low noise humming sound which did not surprise me in the least but is VERY ANNOYING, But i may someday find another use for this to power something.....:)

More testing to do with some other strange combination..........

My theory is, Don't go with what THEY SAY will work, Go with WHAT EVER works....
and I didn't even let any or the smoke out :)
 
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SCPD

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The pulsed output might clean up with an electrolytic capacitor and a three terminal LDO (low drop out) regulator on each output.

The wall warts sound good.
 

byndhlptom

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Altrernate p/s

A) Although it is working for you, probably a poor candidate for long term. These was never intended to be on 24/7, plus they have very poor filtering (the train DC motors don't need real clean DC to run, look at the output with a scope sometime) and as previously mentioned, pulse output will need some extensive filtering.

B) It works at the lower voltage because most mobile/base radios only use the 13-13v directly for the audio amp. Most other circuits are run off of either a 8v or 5v regulator (or both). You probably have noticed lower overall volume (or loud isn't what it used to be).

C) Long term, I wouldn't trust your "Power supply" on "any" of my radio equipment. A good power supply is almost in the same group as good coax and a good antenna.The cleaner, more stable you power is, the longer equipment will last!

Good luck with your Kludge, hope the radios stay working.
 

digitalanalog

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It testing outside the box that leads to new ideas, it's playing all the rules the safe way that NEVER lead to new ideas, I will take my chances and continue to do things that are NOT the way they were ment to be done, that's called creating NEW ideas, and I am NOT scared to loose a few cheap scanners...
 

K9WG

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It testing outside the box that leads to new ideas, it's playing all the rules the safe way that NEVER lead to new ideas, I will take my chances and continue to do things that are NOT the way they were ment to be done, that's called creating NEW ideas, and I am NOT scared to loose a few cheap scanners...
While I totally respect and support your position, I personally would not use anything othet then a professionally engineered and high quality power supply to source my $400 receiver. (This goes for the converted PC power supplies. I have replaced too many fried motherboards due to PC supplies failing).
 

byndhlptom

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Alternate p/s

"It testing outside the box that leads to new ideas"

No problem with testing as long as you know you're doing and do it one step at a time, in a safe way.

"it's playing all the rules the safe way that NEVER lead to new ideas"

The laws of physics don't change a lot. Electronics in general follow these rules. "Playing it safe" means knowing what the consequences may be if stuff hits the fan and what's reasonable / not reasonable. Don't quite agree with the statement though.....

"I will take my chances and continue to do things that are NOT the way they were ment to be done, that's called creating NEW ideas, and I am NOT scared to loose a few cheap scanners..."

As long as you accept the possible damage, experiment away..... I wasn't telling you to stop, only trying to educate a little bit (ie, tell you why it mostly worked). I don't claim to be an expert, but 35+ years of engineering/hacking/fixing electronics has tempered my desire to let the smoke out.

Good luck with your experiments. Be safe. Keep the extinguisher handy.
 

SCPD

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One use for the dual PS is to control the cooling fan motors on an overclocked PC. Place one fan over the CPU, another over the GPU. Adjust speed for cooling vs. noise.
 
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