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Author Topic: Stretchyman 40w GaN TX is sick  (Read 9978 times)

Offline Antennae

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Re: Stretchyman 40w GaN TX is sick
« Reply #30 on: October 07, 2019, 0315 UTC »
I have a cheap-o PS I got from amazon. Its really stable and has its own variable fan. Says it can do up to 15A.

https://www.amazon.com/gp/product/B01CS5G8J6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I've got an inverted L that is about a 1/4 wave on upper 80m where the AM guys are.  There's a ground rod at the feedpoint and thats where I put the tuner. 

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Offline Kage

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Re: Stretchyman 40w GaN TX is sick
« Reply #31 on: October 07, 2019, 0354 UTC »
And this is why I don't sell my old homemade transmitters to people. I've been asked before but always feared something like this would happen and I don't even build on a professional level like stretchy does. Oh those multiple pops... sure someone wasn't making microwaved popcorn in the other room? I could use some reading this thread.
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Offline OgreVorbis

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Re: Stretchyman 40w GaN TX is sick
« Reply #32 on: October 07, 2019, 1041 UTC »
I have a cheap-o PS I got from amazon. Its really stable and has its own variable fan. Says it can do up to 15A.

I don't understand why so many people buy those unbranded Chinese power supplies. I've seen many of those malfunction.
I could understand if the price was significantly cheaper, but IT IS NOT.

You can get a good quality meanwell of that power level for $30
$19 vs $30 bucks isn't a big deal.

https://www.trcelectronics.com/View/Mean-Well/LRS-350-24.shtml

Once you get into the higher wattages, then it makes sense. For those higher powers, eltek flatpacks, and Chinese Velikas are good.
https://www.aliexpress.com/item/32835899833.html

Sorry to get off topic. I'm done.
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Offline redhat

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Re: Stretchyman 40w GaN TX is sick
« Reply #33 on: October 07, 2019, 2334 UTC »
I have a cheap-o PS I got from amazon. Its really stable and has its own variable fan. Says it can do up to 15A.

I don't understand why so many people buy those unbranded Chinese power supplies. I've seen many of those malfunction.
I could understand if the price was significantly cheaper, but IT IS NOT.

You can get a good quality meanwell of that power level for $30
$19 vs $30 bucks isn't a big deal.

https://www.trcelectronics.com/View/Mean-Well/LRS-350-24.shtml

Once you get into the higher wattages, then it makes sense. For those higher powers, eltek flatpacks, and Chinese Velikas are good.
https://www.aliexpress.com/item/32835899833.html

Sorry to get off topic. I'm done.

Agreed.  Mean Well is as bottom of the barrel as I'll go.

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Offline ChrisSmolinski

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Re: Stretchyman 40w GaN TX is sick
« Reply #34 on: October 08, 2019, 0934 UTC »
Hamfests are great sources for cheap but good power supplies. I have seen Vicor switchers for reasonable prices.  I have a Lambda 5V linear supply (9A rating I think) I use to power my netSDR and KiwiSDR. Sure the efficiency is not great and it runs a little warm, but it has a clean output. It runs around 48C but is rated to over 70C.   I keep meaning to put a little muffin fan on it to move some air around but all the fans in my collection are 12V  :)
Chris Smolinski
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Offline Pigmeat

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Re: Stretchyman 40w GaN TX is sick
« Reply #35 on: October 08, 2019, 1935 UTC »
Yep, hamfest power supplies are cheap. If they blow you've got pre-milled box with plenty of spare parts. I've never paid over ten bucks for one.

Offline Josh

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Re: Stretchyman 40w GaN TX is sick
« Reply #36 on: October 10, 2019, 1819 UTC »
Some of those surplus open frame supplies are amazing, had a 10 amp 12v job that you couldn't measure a dip in v or a when you slapped a car headlight across the output.
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Offline Stretchyman

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Re: Stretchyman 40w GaN TX is sick
« Reply #37 on: October 10, 2019, 1823 UTC »
MEANWELL are fine and dirt cheap. I use a 48V 10A one on my 100W design. Coming soon.....

Str.
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Offline KaySeeks

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Re: Stretchyman 40w GaN TX is sick
« Reply #38 on: October 23, 2019, 2025 UTC »
These modern transmitters have a lot in common with switching supplies...both operate in switch mode (class D or E) and the waveforms feeding the power devices have to be right or the smoke comes out.  I too spent a few years working on SMPS's exclusively and the first thing you did before bringing up the mains was testing the drive waveforms.  If they don't look right, your mosfets won't last long...
Its not like the tube days when you could swap a tube or two and see what happens.  More often than not in solid state, you're greeted with pops, bangs, and puffs of smoke.

I'm in violent agreement with the above.
Just somebody with a radio, a computer and a pair of headphones...

Offline Charlie_Dont_Surf

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Re: Stretchyman 40w GaN TX is sick
« Reply #39 on: June 27, 2020, 2100 UTC »

So I hooked up my 24V powersupply into the  TX and it made a couple pop noises and then it quit working.  The PS is an AC to 24V DC converter.

I think I may have had the transmitter "on" and my PS was "on" when I plugged the PS into the TX. 

It made a pop noise in the past, so I've been plugging them together with them off.  Then I first turn on the PS, and then I turn on the TX.  But I didn't do that this time and now it doesn't work.  I checked the fuse and its good. 




I see that this problem has been catching on. Maybe it is caused by a virus?
« Last Edit: June 27, 2020, 2122 UTC by Charlie_Dont_Surf »
I don't STRETCH the truth.

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Every minute Charlie squats in the bush, his signal gets stronger."

 

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