Class D crapout

[flintstone mop]

Hello
The saga goes on trying to use the station and things happen. I was reworking the T/R relay problem and also wanted to upgrade my PTT lines. My UNisolated soldering iron touched the PTT wire for the Class D and POOF!!!!
The little 10A fuse was popped inside, but replacing only revealed that the output power was down and no modulation, THEN the little guy just quit making anything.
Any one else have this problem?? I was warned about using an isolation transformer, and didn't................now I have to pay the Piper. There was a lot of threads about these neat transmitters. Maybe this is a warning to other users to get an isolation transfomer hooked up TODAY!!!!!!!!!!
Like I have excess money to spend on repairing equipment that I cannot even see the components!!!!!!! DAM
Fred

[Rick K5IAR]

Sorry that happened to you, Fred.  Before I got my soldering station I did the same thing on more than one occasion.  You're much braver than I to even try to fix those dinky, little components.  My eyes are too bad, my fingers too fat and my coordination shot!     ..but I'm still on the right side of the grass!   

Merry Christmas...
Rick/K5IAR

[ka3zlr]

Oh Fred, man sorry to hear this happen...wish we lived closer..I'm still semi stable with component level work...but i am slippen as age is closing in on me too.

Hey is there any warranty on the thing...wonder if he'd help a brother out...

[N3DRB The Derb]

last job I had involved a ton of surface mount repair and rework. Of course they had the tools to do it with, like hi power bino viewers and such. I loved it.

When I lost my left hand, that was da end of dat. no more surface mount. But I can still do big old obsolete junk.

[ve6pg]

...geez fred, sorry to read this....i shud have my class d rig, some time in january...i will take care, now knowing there may be a problem...tim..sk..

[flintstone mop]

I haven't heard from Bruce Franklin yet. I'm sure he wants to spend time with the family.
It's ashame such nice technology can go up in smoke from "engineered shortcuts". It may be nice to hold 200 watts from an AM transmitter in your hand, but one bad move with something grounded and your done.
I built a nice little 500vdc power supply for my Elmac from the ER mag, but you better not flip that AC plug around, if it's connected to other equipment using the safety ground. I used a three prong plug to prevent that disaster from happening. The editor questioned the author about safety matters, but published it any way.
Warning to ALL buying the K7DDY products.......If Bruce suggests an isolation transformer...............GET ONE!!!! Before the same thing happens to you.
I'm sure he will not repair these things for ever if we are not taking the proper precautions.
Fred

[AF9J]

Hmmm,

I didn't know Bruce Franklin was the one involved with the Class D transmitters.  He's the one who sold the Index Labs QRP Plus rigs.  I had one of those for a number of years (sold it in 2005 on eBay).  It was an OK rig, but it had its issues (I ended up having to do a couple of factory recommened mods to mine in the mid 90s).

Ellen - AF9J

[KF1Z]

The Neutral line in runs into the transmitter as a "floating" zero voltage point I guess.

The only reason for doing that is to eliminate the need for a power transformer in the package.... (as far as I can tell).

In the documentaion for the "Jr" model, there was a warning to use an isolation transformer especially if testing with a scope.    "...Or bad things will happen.."

[W1RKW]

This begs a question, why be soldering with the xmitter plugged in?

[flintstone mop]

YUP the power was off, the AC plug in the socket. I just touched my grounded soldering tip to the PTT wire going to the transmitter, that was connected to a relay and poof!!!!
Bruce recommends a 500va isolation transformer to prevent the poof.
Yes, there's a warning about "bad things happen" on his website.
It's my bad and now I have to pay for it. I forgot about the bad things.  Nothing wrong with Bruce's stuff. I'm not used to "engineered shortcuts".

Fred