Stretchyman 40w GaN TX is sick

[Antennae]

I have a Stretchyman 40W transmitter I use for communications on the ham AM band. Got good reports BTW.

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. 

Any ideas whats wrong? Maybe I can replace something? 

[Kage]

Damn I was hoping this post would be about how sick, as in awesome his transmitters are. He seems to be quite the tech guru and knows a hell of a lot more than me on class D and E hands on work. Sure he will chime in Really no idea why I am replying, just thought the title of the post was about how cool his little rigs are and I probably drank a few too many beers or something.

[Stretchyman]

Yeah I thought the same!

Why not ask me...

Str.

[Stretchyman]

I still await a reply and have PM'd you 'ANTENNAE'

I'm still somewhat perplexed at your post and lack of response......

When inquiring about any issues with a product purchased I would have thought getting in touch with seller/designer would have been the first thing to do?

PLEASE reply to my PM.

Regards

Stretchy.


p.s. BTW when turning on ANY supply it wont be regulated and pump-out A.C.

There's lots of things to try and maybe its just a burnt connector.....

[Antennae]

Hold your horses dude!  Here's my response why I posted this here:  It was to see if anybody else had this problem.  And if a solution was given on this post it would help other viewers out in the future in case theirs popped.  Its already probably going to help people out because now they know how to plug in their power supply (and what can happen if they don't do it properly).  I'm grateful and fortunate that Stretchy is here to help.   

[Pigmeat]

Did you check the fuse in the power supply? You can give both the trusty smell test while they're shut off. If one smells like ozone and the other doesn't you know where your problem is before you go poking around.

[Antennae]

Hey Pigparts, they both kind of smell electronicsy.  The supply as a problem is a good point. But I tested with a battery and still no avail. 

[Antennae]

I posted it for sale in the For Sale forum.  Shipping included.

[Antennae]

FWIW, I removed the old MOSFET and it failed the test with a multimeter.  So I ordered a new one and installed that today. It worked but it made a big pop noise.  I turned it on and off and it stopped working again after the 3rd time. 

[Stretchyman]

TBH I'm not happy as one, you have refused my offer of (free) help and two, messing about when I have already offered advice as to where to start.

You have surely assumed (somewhat incorrectly) you would be charged some astronomical fee to fix the unit when I have in the past never charged a cent and even paid the return postage.

For any future purchasers of any of my products, just send it back, you wont be charged.

Str.

[Antennae]

Its not all "unicorns and fairy-free," it costs money to ship it there and time/work to pack it up to send it on an international journey as well as the time without a transmitter.

Messing about was fun.   

I think one of the integrated circuits  broke and that blew out my transistor. 

Does anybody else have problems with their stretchyman transmitters? 

[JimIO]

I worked for years troubleshooting SMPS's. You have to replace all of the bad components before you power it up. Sending it back to the guy who designed and built it is a no brainer.

[redhat]

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.

I understand the frustration, but you need the have the tools and know-how to work on these things.  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.

+-RH

[Josh]

Tried to see what voltage the ps is sending to the fet yet?

[Antennae]

I see. Thats why Stretchy had me check it with an oscilloscope.  It has a sinusoidal wave where there should be a square wave. 
Thanks for your input, I'm done with it for now. I'll use it as a decoration, kind of like a star wars model with battle damage.