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Author Topic: tenma 72-6180 power supply info?  (Read 182 times)

WB7TDG

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tenma 72-6180 power supply info?
« on: May 10, 2022, 09:08:05 AM »

Picked up and old tenma 72-6180 40 amp (?) power supply at a swap meet..
works fb and looks pretty much new, has good regulation and output voltage is stable, but has a very loud fan.
anyone know anything about this little beast? did they come with any kind of overvoltage protection?
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VE3RWY

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Re: tenma 72-6180 power supply info?
« Reply #1 on: May 10, 2022, 06:03:17 PM »

I have one of these too and you are correct, a noisy beast.  I bought a motor speed controller from Amazon, mounted it on the back of the case and wired it in.  I turn the speed down to about half what it originally was.  I don't run the Tenma very hard and it barely gets warm to the touch.

https://www.amazon.ca/gp/product/B07D28WBXF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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WB7TDG

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Re: tenma 72-6180 power supply info?
« Reply #2 on: May 10, 2022, 06:36:30 PM »

I am currently running my fan with a 50 ohm resistor in series with the negative dc fan lead an am also taking a gander at those little motor speed controller board that regulate by temperature. epay has them...
I also turned the fan around and it seems to be even less noisy but better air flow.
I never intend to run the little tenma at much more than 20 amps or so...just enough to fire my ic 7300 and a uhf/vhf rig.
« Last Edit: May 10, 2022, 06:50:55 PM by WB7TDG »
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WB7TDG

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Re: tenma 72-6180 power supply info?
« Reply #3 on: May 11, 2022, 04:30:08 PM »

did a little calculation....my ups can calculate wattage use. have 3 different power supplies...
load 17 amps at 14.2 vdc output using ic-7300 transceiver and dummy load at 100 watts key down

Diamond gzv4000 40 amp switch mode power supply.....280 watts consumption
Astron 35a power supply....................................................388 watts consumption
Tenma 72-6180 power supply.............................................483 watts consumption

with radio in recieve (idle) was between 3-5 watts between all 3 power supplies......the tenma has 27 volts or so feeding the pass transistors!
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VE3RWY

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Re: tenma 72-6180 power supply info?
« Reply #4 on: May 11, 2022, 06:28:23 PM »

I picked up an Astron RS-50A because it doesn't have a fan.  I thought I had my problem solved but the Astron has an annoying hum.  I don't want to give up either so maybe I'll end up with three power supplies as well  ;D
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WB7TDG

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Re: tenma 72-6180 power supply info?
« Reply #5 on: May 11, 2022, 08:48:44 PM »

that's what my 35a had and still does to a small amount...
I tightened the bolts holding the lamination together on the transformer, drove some small wooden wedges between the center of the laminations and coil turns and then painted some expoxy on the top, bottom and sides of the lamination. had a 50 amp astron also don't recall it had any hum but the transformer would couple with the case and generate heat.
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VE3RWY

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Re: tenma 72-6180 power supply info?
« Reply #6 on: May 12, 2022, 08:15:41 PM »

That's pretty creative trying to nail that hum
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WB7TDG

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tenma 72-6180 power supply mods
« Reply #7 on: October 12, 2022, 01:09:15 PM »

Was going to do a little note to my blurb earlier about my tenma power supply but decided to start a new thread...
here are some mods I have done to my little power supply project so far...
two speed fan mod...100 ohm resistor in series with d/c power to fan...bypassed by 40 degree thermostat. tested on power supply dummy load and works great!
a/c inrush current limiter...NTC 2.5D 12 amp varistor
1.5KE15A zenier diode across d/c output for surge protection.
debating to switch 2 line a/c cord to 3 line cord but not sure if it will make any difference.
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