As you all know storms have been popping up all over the U.S. in the past 2 weeks. Kentucky alone has had three or four days of rain/thunderstorms with cloud to ground lightening.
As you all know storms have been popping up all over the U.S. in the past 2 weeks. Kentucky alone has had three or four days of rain/thunderstorms with cloud to ground lightening.
Well ive been running the sstran on the short wire antenna that came with the kit and the range was limited to the inside of the house and about 20 feet outside.
It was not intended to cover more than that since i wasn’t ready to mount it outside. I was just using it to listen to different programming provided by a mp3 player set on shuffle.
When i pulled in i noticed a carrier with no modulation on 1520 khz.
I just figured the battery had died in the mp3 player and would replace the battery next time i wanted to listen to something different than what i play on 1700 khz. I just shut off the sstran and went about my business.
Today i fired up the sstran and the mp3 player and noticed the modulation was low, really low. I checked the player and the controls on the sstran, i even plug in a patch cord from 1700 khz to see if the problem was the player or the audio cable.
Unfortunately that didn’t fix the problem. I have the same carrier i had before I lost modulation. So something must have popped while i was away from home.
I am wondering if lightening might have had something to do with the sudden loss in modulation or perhaps something i did, maybe bad soldering on my part.
Anyways, ill be tearing into that when i find the time, it couldn’t be much. Could it?
Before i go, the modulation is just barely audible and if you crank up the gain, modulation you get a fuzzy sounding noise.
With all the controls turned off i get a clear hum free carrier.
Someone else had this problem awhile ago
I think if you do a search on this site you might find the answer to your problem. I seem to recall someone else having a similar problem with their SSTRAN after a thunderstorm. Sorry, I don’t have any experience with that since mine has worked flawlessly since the day I bought it.
I would check the voltages in the audio section, the audio IC, and also the two transistors in the output. Common sense would suggest that it’s one of those transistors– probably the one that has audio applied to it– because they are closest to the antenna. But I have no definitive knowledge to support that. Obviously the synthesizer is still locking, so the problem is not in that area.
Puzzled
This is puzzling me.
The sstran still has no audio unless i connect the ground wire to the mixing board or screw on a power outlet.
After connecting the sstran to a outlet screw the audio jumped back in there just like it was before the component/s broke down.
Sounds like the output transistors to me, I have a digital volt/ohm meter now and as soon as i have some free time i will open the tx up and probe around. Also it looks like i will need to make a trip to radio shack soon, i seem to be running out of parts.
Is there other sections of the tx i need to check?
The IC would be hard to troubleshoot with just a ohm meter so if i replace the output transistors and that is not the problem then as Weak-AM said, i may have to order another IC.
Breaking Ground
Sounds to me like a problem I had with an old laptop.
Plugged into my laptop earphone jack, 110 Vac accidentally came into contact with the device connected to it. A brief flash later no audio would come from the earphone jack. Although, it still played from the internal speakers.
By trial and error I found that connecting a ground to the connector plugged into the laptop, stereo music once more poured from the earphone jack.
What had happened was the ground trace on the laptop PC board where the earphone jack is connected burned in two. Bridging the burnt ground trace resolved the problem.
Perhaps you have an open ground connection somewhere in the audio connection of the SSTRAN.
Check the ground foils
I agree with MRAM. Check the ground foils to see if you have an open connection. Also check those jumpers that go across the ground chokes. You should probably have the audio input ground jumper installed; otherwise the input circuit picks up a major amount of hum in most installations.
Breaking Ground
Sure enough, the leads around j1, j2, c1 and c2 were burned.
The capacitors at c1 and c2 were untouched but i replaced them to be on the safe side.
There still seems to be something else out of wack probably a resistor but i have the sstran running again. Left a nasty burn mark on the cabinet too.
Edited: Still not right. The damage must extend to one of the IC’s.
I am not able to tune all channels between 530 to 1200 khz.
In order to make things easier on myself when repairing the sstran,
it was reconfigured to work with the supplied wire antenna.
For some reason I cannot tune the transmitter to just any channel, it is skipping alot of them and appears to not follow along with the manual.
I have a strong signal on 1230 khz right now and it worked fine on 610 khz yesterday. I just cant tune it to a frequency I want to use.
Dip switches were checked and double checked for poor solder joints as well as the chokes and ic’s. Where else should I look ?
Thanks