i got a 2004 model sstran, and the PLL is not functioning correctly. i get a carrier on 1410, and just a little fluttering on the freq i actually want it to be on. i've tried changing dipswitch settings and it doesnt work on other freqs either, just 1410. has there been any revisions since this early model? this thing has been on and off the back burner since 2007. all joints got re-flowed with solder and continuity checked for shorts. IC's have been replaced. i've done kits and homebrews that have been more successful and i wouldn't be suprised to find a break in the connection somewhere on a PCB trace, since im out of ideas otherwise. not into dropping more money for a factory repair, since 98 bucks is more than enough to pay for milliwatts and im a polak bastard farmer with not a lot of money to throw at things like this. starting to think i have a lemon
Despite it's very fair low price the AMT3000 is a very sophisticated and professional AM transmitter worth saving.
My oldest one is from about 2005 and it started having trouble in 2012, but all I had to do was remove and re-seat the ICs and now it works like new.
Maybe sell yours to someone who has the means of repairing it and eventually get a new one? Maybe step up to the AMT5000.
i threw new IC's in and reflowed all the solder joints. mine never once worked since i got it. if i can get it workin, i might just sell er since i'm a user of the anklebiter setup, which im gonna improve with a PLL soon enough
any other ideas welcome. the IC's i used are off of ebay. might have to mess around with a few caps perhaps? idk, im definetly MF'ing this thing. i've done everything from voltage to continuity checks and im just coming up with a blank. as i said, it would not surprise me if there was a break in the PCB trace somewhere at this point
I've seen electrolytic caps dry up and cause alll kinds of headaches. Mite shotgun some of them around the PLL circuit..
Check that the resistor network connected to the DIP switches is not in reversed. It is easy to get this wrong.
Neil
resistor network is in correctly. i'll try recappin the electrolitics i guess
no dice. i read in the $12 PLL thread that the 4046 can vary in capacitance tolerances so is that an area i should attack?
RADIODIRTYSPRINGS1700 you said you replaced the IC chips in your AMT3000, but you didn't say why...
Was there something wrong with the original chips?
It seems to me that if you are simply gambling that one or more ICs might be bad, you'd also have to remove and replace every transistor because they too might be part of the problem. Or a capacitor. Or a resistor.
Also, what is an "anklebiter setup?' Is it like an ankle bracelet for house arrest?
(kidding. Only kidding.)
I'd never be able to get a night's sleep until I hade mine repaired.
the original 5v regulator wasn't workin right and dumped 15 volts down that line so i assumed that the IC's were kicked
is that an area i should attack?
Possible but not likely. Years ago I did designs with the 4046 and noticed that the spread for the free running frequency was quite wide but so was the capture and lock range so the IC would always lock in my applications.
The best way to troubleshoot this would be to use an oscilloscope. If this is not possible then the next best would be to measure some voltages. From this you could tell if the oscillator and counters are working.
Am I correct that this kit never worked? This would give high probability to some construction problem. I had a kit which I built 50 years ago that never worked quite right. Despite checking and double checking it many times I could not find an error. A few years ago I decided to find out once and for all what the problem was and discovered that I had transposed two resistors. I had missed this error probably because I was so familiar with the assembly that I didn't really check it carefully and apparently kept making the same mistake each time I checked it.
I have noticed that the color code paint used on beige resistors doesn't always clearly appear as intended. For example, it is easy to confuse orange with red and violet with black. You might try measuring the resistors in circuit. The resistances should equal or be less than the nominal value.
Neil
i went through the resistors a cpl of times visually with the build instructions, and yes, you are right, this thing never worked.
Have you contacted Phil? Perhaps you could send it to him for repair.
yes, and as i previously stated, im not tryin to drop any more money into this.
RADIODIRTYSPRINGS1700 I know there are several of us who would love to have the chance to go over your transmitter in the hope we would see something you might not have noticed.
Can you take a photograph image of it?
The hardest part about a picture is getting the lighting just right so details come through with their right colors and no glare.
Somebody would have to tell us how to post a picture on this website.