Post by HighMountainRadio on Oct 12, 2018 9:30:38 GMT -6
Greetings To All From HighMountainRadio !
I am in search of anyone who may own a HLLY Model TX-30S FM broadcast transmitter. I am repairing one of these units for a fellow enthusiast and I need to be able to identify a component that is missing from the Audio Input circuit board. I have included a picture of the circuit board showing the missing component's location on the board located between the fuse holder and the 3.5 mm Microphone Input Jack. The missing component on this transmitter obviously exploded, causing a bit of circuit board track damage but I will easily be able to resurrect it once I am able to identify exactly what component belongs at that location on the circuit board. My initial assumption is that it may possibly be a resistor or electrolytic capacitor that vaporized. If anyone can please tell me what this component is and it's value I would surely appreciate it immensely ! Thank you very much in advance for any assistance you may be able to provide ! As I am sure you are already aware, attempting to find a schematic diagram for this transmitter is next to impossible so I am hoping that someone out there who may own one of these transmitters would be so kind as to have a look and let me know what you see at that location on the circuit board ! I have attached a picture showing where the mystery component was once located for reference.
73... Spooky...
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"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
I have an ST-7C which is not exactly the same model, but a lot of these Chinese transmitters seem similar. Mine has a cap there and it also has one on the audio line in jack. Does yours have one on the line in also? That would be an easy way to find out what it might be. I can't desolder it from mine to check the value because it has this upper circuit board soldered with pin headers that I'd have to remove all of them to be able to remove the component. In addition, it looks like on mine the one pad is going to ground, but I can't be sure. If it's going through rather than ground, it's probably an audio coupling cap, in which case I don't think the value is very critical (not sure, but like 1uF should work).
I have an ST-7C which is not exactly the same model, but a lot of these Chinese transmitters seem similar. Mine has a cap there and it also has one on the audio line in jack. Does yours have one on the line in also? That would be an easy way to find out what it might be. I can't desolder it from mine to check the value because it has this upper circuit board soldered with pin headers that I'd have to remove all of them to be able to remove the component. In addition, it looks like on mine the one pad is going to ground, but I can't be sure. If it's going through rather than ground, it's probably an audio coupling cap, in which case I don't think the value is very critical (not sure, but like 1uF should work).
Greetings Ogre !
Thank you VERY much for your swift reply to my SOS ! That info helps a LOT ! I suspected that it WAS a capacitor at that location, since yes, one side does go directly to ground ! I am mystified as to just HOW this capacitor came to meet it's demise, especially in view of the fact that it does appear, in deed, to be simply an audio bypass capacitor ! I am working on this HLLY TX-30S for one of my customers who purchased one of my model 'HMR3F' 3 Element Folded Dipole FM broadcast antennas that I sell on EBay. It's been 'interesting' communicating with the owner since he speaks NO English at all and my Spanish is pretty limited ! Thanks to 'IM Translator' an online language translator, we have been able to communicate quite well ! I am able to read Spanish fairly well but to construct sentences or speak it, that's a whole different story ! lol !
After testing the unit thoroughly I was able to determine that the HPA module as well as the control module are working properly and I am able to easily drive and control it's output from 0 to about 25 watts into a 50 ohm dummy load without issue. It does fault out somewhere above 25 watts and gives me a "Check Antenna" warning message on it's display but I don't believe there is anything wrong, I believe the specs are just a bit overrated. It states in it's specs, 0-30 watts but it's more like 0-25 watts in reality. Still not a bad little transmitter overall but most definitely way over priced at $460.00 !! This unit was given to him by a friend who upgraded to another transmitter. I wrote an e-mail to HLLY to inquire as to whether a replacement audio input/PLL module can be purchased and I am awaiting their reply but I suspect the answer likely will be NOT AVAILABLE as they likely will want to simply sell you a new unit at $460.00 ! I am fairly comfortable working with SMA components and my eyesight, with the assistance of eye loops has been quite cooperative thankfully.
I have not yet had the opportunity to visit my friend with a spectrum analyzer to check it's spectral purity but it shall be interesting to see what that is like ! By the way Ogre, if you care to e-mail me directly, my e-mail addy is: highmountainradio@gmail.com Take care Brother, hope all is well on your end of the rainbow ! Spooky..
"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
