so with these chips, i managed to make the tompolk PLL work with 13.8V. no such luck with the SStran 4 chip PLL on 5 volts. since i found that unsoldering components also ruins the PCB trace, im gonna just remove everything in the PLL and jumper in the tompolk PLL since that's a cheaper alternative to giving SStran $30 bucks for the privilege rectifying the fact that the original chips that came with this are junk apparently. no, i did not install any incorrect values. i've more than quintuple-checked all of that, and i've had this dead transmitter for literally a decade and have tried multiple times to get it going on the correct freq. it sucks that it's gonna be ugly, but that's still better than not working at all
YOU SAID: "...since that's a cheaper alternative to giving SStran $30 bucks for the privilege rectifying the fact that the original chips that came with this are junk..."
Wa4JM SAID: "The parts used by SSTRAN are not junk."
I have two AMT3000s and they are of the highest quality.
The oldest one got jittery after many years, so I carefully removed and cleaned the chips and re-seated them, now it's on the air strong.
$30 is a very fair price for fixing the unit, it would be worth doing, and the people at SSTran will absolutely repair it like new.
yep it's happenin. im even using the same chips i replaced the originals with in the external PLL. and the IC sockets on the board itself are just there to serve as jumpers sockets. there are def no cold solder joints and im no dummy when it comes to building things. i just was never able to make the PLL lock, despite trying an and off for a literal decade. even when it had the original chips on it. im just sick of seeing it shelved and decided to go polak on it. it's goin into a metal case and getting set up on the air and im gonna be done with it. i got better things to spend 30 bucks on, like beer 🙂
I vote for beer.
IF YOU'RE NEVER GONNA FIX IT SEND IT TO ME.
haha nope. its gettin polak-rigged and put on the air. i tend to have better luck with full-on homebrews than i do with kits.
and dont worry, i had a ramsey AM-1 that was modulated with a 386 and darlington and had a 2n3053 output that put out around 1/4 watt dead carrier. that kit turned out wildly different than it's original design as well haha.
That SSTran has to either be assembled wrong somehow or has a defective part, my AMT3000 survived a lightening strike only popping a resistor of all things.
The metal case does sound pretty interesting however, so let us know how that goes. FWIW Phil over at SSTran will do a lovely job repairing your unit if you ever cave in.
i'm hard-headed as all hell. i will not cave lol
It is possible the the pc board is faulty.
if that's the case, i can't justify throwing more money at a manufacturing f-up. thank god for IC sockets since i can just use them to jumper in my own (working) PLL
I am a defender of SSTran Products, and the AMT3000 transmitter is manufactured to the highest standards of kit technology.
I take it personally when an AMT3000 circuit card gets accused of manufacturing F_up with no proof whatsoever.
A circuit card manufacturing defect would be traceable, observable, and easily found by a person who knows what he's seeing, and if you haven't found a defect then there isn't one.
Could be a bad part... maybe an open resistor or goofy capacitor.
Main thing is whatever is wrong with your AMT3000 is findable and fixable.
I had a memory problem once with an Amiga 3000 Computer, and after several motherboard exams, I discovered that the first IC socket in a row of sockets had no Pin 1, which was easily not seen.
You need to use a scope, to look at supply rails, pll ref freq and divider output going in to vco, and loopfilter responses, as well as oscillator output.
Then it will become obvious what is wrong.
Paul.
Hi,
I need to agree with Carl. Compared to chinese built electronics these days, the AMT3000, if assembled correctly is like a tank. I've had one mounted outside for the last 5 years through hot summers and freezing winters. Still works great. I just need to clear vines off the mast once in a while.