Broken FM Xmitter?

[micky]

About 14 months ago, I bought something that looked like any of the links below. It worked great, to let me listen to computer audio (such as web-radio) anywhere in the house or even on the car radio. I used it in my bedroom, the bathroom, and the kitchen, on different FM radios.

Left it on most of the time. Last week it broke.

Any chance I can repair it? What should I do?

I've turned it off for a day, then unplugged it for a day. Changed frequencies, adjusted volume, replugged input.

If I open it up, will I see burn marks somewhere? Cold solder?

Is there something I'm missing? (I always feel anything can be fixed.)

(There IS one thing I missed. Do y ou know what it is? But I just checked and it's not the problem.)

With the input volume all the way up, and the volume of the receiving radio all the way up, the radio output is about 1/10th or 1/20th what it used to be. Just enough to know that something is happening. Screen on the xmitter still lights up and displays the xmission frequency.

I'd never tried a mike before, and it's conceivable it never worked, but now, when I plug in a mike and turn its volume all the way up, stand halfway between the transmitter and the radio and yell, no trace of my voice from the radio.

It never felt hot.

They stopped selling my exact thing only 6 months later, but i'm sure the warranty was for no more than a year.

This is the same brand but when I click on my previous order, it says "We couldn't find that page." and it doesn't go here:

$80 - 10. Still the cheapest. Is that the reason it broke after only

15 months? (Mine was called "Signstek 0.5 W 05B Dual Mode Long Range Stereo Broadcast Home FM Transmitter with Antenna and Free Audio Cable Fashion Black " Return window closed on Mar 4, 2020; Product support window closed on Aug 1, 2020) It gets 4.6 stars on 479 ratings! 90% give it 4 or 5 stars, but so would I have for the first year.

Only one review said it worked at first and failed (after 2 months). None of the other complaints applied to mine.

Do I have an alternative than buying basically the same thing again?

You can see that the first 3 are all the same in terms of size, shape, controls, jacks, antenna.

$90

$80 This makes reference to an AUX jack, but from the pictures, plainly they just mean the mike jack. That's fine.

$99 - 20%

To get back some of the money I lost on the broken one, would it be wrong for me to start my own church?

$120 Mine was cheaper, I guess because it had no RCA inputs, which I have no use for.

There are more, there were more at the time. Did I make a mistake by buying one that was $10 less than tthe others. $65 instead of 75?

This brings up the same question that I raised with the auto-vacuum-pressure tester, one of which was 33% higher than the other which appeared identical in every way. Are ttwo such things the same thing with different pricing, or do they manage to imitate a good one and yet make the imitation junky? I know t here is no single rule but what is your experience?

Functionally similar, based on knobs and jacks, but knobs are closer to the ends of the panel, it's silver instead of black, and it's twice the price $200. Does that mean it will last twice as long, 10x as long?

$160

[micky]

Thanks, for the comprehensive answer, Rod. I read the whole thing but had started this already. Later, I may have a few wiseacre comments on your comments. ;-)

The thing I said I'd left out, the debugging step that I hoped you'd all notice, was that I didn't check the output voltage of the adapter. Maybe it was enough to light the display but not transmit. However it was fine, 12v.

While trying to pick a replacement, I finally noticed that a few of htem were listed as 0.1/0.5W LCD PLL. Even when I saw two wattages, I didn't remember that mine had that too. It took 2 or 3 minutes and it gradually came back to me.

So where is the switch to set the output power. Every knob and switch was accounted for. So let's find a manual. Not so easy.

Finally, googling fm transmitter 0.1/0.5w pll manual gave 53 hits but the 2 I looked at referred to manually scan.

Then in little grey letters I saw one hit was a pdf file.

This is the $200 one. I still have no other evidence it's better than the $60 one, but one thing it has is that dagoelectronics has a pdf file all about it including instructions!!

Instructions I had completely forgotten, even that they existed. I thought I just plugged it in. In fact, that the instructions are the same as for my cheap one is just a little more evidence they are the same.

I had had power failures before in the past year but it has worked fine the entire time. They didnt' change it from high power to low power. I don't know what did this time.

This is what I was "missing". I'm glad I figured it out before I bought a second one.

Still 3 problems. 1) I did steps 1 and 2 but thought i was done, didn't pay attention to step 3, and it doesn't work. 2) I see that it's set 108.00 so I do step 4, and think I'm done, but it doesn't work. 3) I never yet did steps 5 and 6 and that might come back to bite me, but I did read and do steps 7 and 8, and it seems to be working now!!

Instructions:

Power Adjustment Menu ?Toggle from 0.5 Watts to 0.1 Watts Applies to all 2010 V1.2 versions or later with two level power adjustment: High power (H):> 0.5W/500mW(Default); Low-power (L): <0.1W/100mW NOTE:The power switch (H) is actually like an Enter button when in the Power Adjustment Menu. Proceed through all steps, if you have any issues after toggling the power level, please refer to these steps and set to the defaults and try again.

1. First press and hold the Power Switch/MENU(H) while inserting the power adapter into the Power Jack (A).
2. Release the power switch (H) after LCD screen displays the "H" or "L". Use the Frequency Toggles ?/? (I). Press ? or ? to toggle the LCD screen display between H or L. Again, "H" is the output power > 500mW; "L" is. the output power <100mW.
3. Press the Power Switch/ENTER(H).
4. The LCD screen displays the default setting of "108.00MHz"and the Mute Symbol will be displayed meaning it is not transmitting and this will be displayed through Step 7. This is the Highest Frequency the transmitter will display. Through the ?/? (I) it can be changed from

0.10?153.00 MHz.

1. Press the POWER SWITCH/ENTER(H).
2. Now the LCD screen displays the default setting of "76.00MHz". This is the lowest frequency the transmitter will display. Again, through the ?/?(I) it can be changed from 0.10 ?153.00MHz.NOTE the lowest frequency high-end cannot be higher than the highest frequency selected in Step 4.
3. Press power switch (H). Wait 3 seconds to exit the Power Adjustment Menu and LCD screen will display "OFF".
4. Again press the power switch "(H) and the transmitter will power on and transmitter will begin transmitting.Now reselect the broadcast frequency.If the broadcast frequency is locked and you cannot toggle, repeat all steps and reset the High and Low Frequencies to defaults!

More stuff. Formatted and easier to read at the webpage above.

Tips and Tricks 1.Antenna: Always operate the transmitter with asuitable antenna or 50 Ohm dummy load to the output. Failure to comply may cause serious danger or destruction to the output stage of the transmitter and void warranty coverage. POWER JACK(A)ANTENNAPORT(C)AUDIO INPUT (D)FREQUENCY TOGGLES/POWER SELECTOR(I)AUDIO VOLUME CONTROL(F)POWER SWITCH/MENU/ENTER(H)MICINPUT (E)MIC VOLUME CONTROL(G)RCA INPUTS(B)

2 Power Supply: Do not exceed 12V 6A power supply. For best results use a Fail-Safe supplied power supply.

This one is a surprise:

3.MIC: Do not use a MONO plug-type microphone, doing so may cause permanent damage and void warranty coverage.

I don't know what it means to have a stero mike anyhow, when it's all on one stalk only 1/2 inch wide, but the plug on the end is indeed TRS, stereo.

4.Sound: When using most FM transmitters with a PC or MAC computer the volume level will need to be optimized at devices: (1) transmitter (2) computer sound card, (3) Media player software, and (4) FM receiver radio. If necessary, you may consult the instructions of the audio device to toggle the Equalizer. If Bass is distorted, or static is heard, minimize bass levels in the input device.

TROUBLESHOOTING:

1. Distortion/Static:Make sure to set the volumelevel of audio source device and the transmitter at MOST at the50% and adjust up from there. When using transmitter with PCs or devices with Bass Boost or higher bass settings, you will want to minimize the levels for the transmitter does have a built in pre-amp which further amplify the bass and it will be broadcast as static or crackle. Also note that this transmitter?s sound output level will not match local radio station?s volume levels.

1. Transmit range is weak: The transmit range will vary as per your environment, antenna type, power setting, and/or frequency setting. You may need to upgrade the antenna. Placing the antenna on the highest altitude inside or outside of a building with the least amount of obstacles will give you the optimum range.Please note that the average broadcast range with the stock rubber duck antenna is around 300 feet to a vehicle stereo. Receiver units with weaker strength antennas, may not get even half of this range. For best results, check out our other antennas, transmitters, or contact us.

2. Constant hum on radio/when broadcasting: Most likely cause is the audio cable or MIC but it can also be the power supply, input device, or antenna. HUMIS RARELYCAUSED BY THE ACTUAL TRANSMITTER!Proceed with the following steps to attempt correcting the hum: 1) To attempt to correct please start by assuring all cables are isolated from all power sources and that nothing is coming in contact with the Antenna or Antenna port. 2) If the hum persists, remove the audio cable and MIC from the transmitterso that all that is connected to the transmitter is the power supply and antenna. 3) If the hum ceases, it is either a bad audio cable, the audio cable is resting on another wire that is causing the hum, or the input device is causing the hum. You may also have to separate your transmitter from your input device. We do have Audio Cables in lengths up to 100 ft. Also, use of input devices with battery chargers has been known to cause issues with hum/feedback. 4) If the hum persists ensure the antenna pieces are snug. In addition the antenna should remain in an 90° position. If it easily tips over, the antenna may be the issue. 5) If hum persists, the only thing left is the power supply. Contact us if through this troubleshooting leads you to believe that itis the power supply or antenna.

1. Transmitter will not power on: Please test with either another 12 V power supply briefly with the transmitter. If you do not have another power supply, try the transmitter power supply with another device that accepts 12 V of power, or test it to see if it is still functional. If you find that the power supply is the issue, or if you do not have the means to test it, please contact us and we can make arrangements.

2. Transmitter powers on, but not transmitting: Please ensure the Mute Symbol is not displayed to the right of the frequency. If it is, please refer to the Power Adjustment Menu Instructions. If it does not transmit still and the mute symbol is not displayed, then please contact us.

F-S Electronics 2014©32.

Amazingly complicated for a little thing, huh.

Micky

Notes; obsolete now: In alt.home.repair, on Sat, 24 Apr 2021 19:02:07 -0400, micky [e-mail] wrote: .....

Has $2 lavalier microphone included

Also has a fan and a telescoping metal antenna. Others have no fan and stubby but unbreakable antenna.

RCA jacks, no sign of a fan, inc. rear view.

$80-10 St-7c with fan 4.4 stars on 775 revies

$100 no fan 4.5 stars on 9 reviews.

$96 4.6 stars on 26 ratings 0.5W

$70 5 stars on 1 rating 0.5W

[gfretwell]

I imagine if you know a ham he could fix it but you probably need a scope. If this thing is old and you really like it. It might be worth fixing because the FCC tightened up on the regulations and the newer ones are not as powerful. I had the one Radio Shack sold in the early 70s. If you added a 30" car antenna to that it would get out close to a mile. (Inside my apartment to my car radio out on the road) I have a newer one that breaks up if I get much past the mailbox. My

900mz stuff works better.

[trader_4]

Good, fast, cheap. Pick any two.

[gfretwell]

I think it really has more to do with what the FCC allows under part

1. They are balancing reasonable performance with interference complaints and they lean toward eliminating harmful interference. It is usually your local ham who will be complaining. I have some kind of funky looking folded wire antenna on my 900 mz transmitter that was designed for 900mz drone controllers and it gets out about 100 meters reliably to my headset.

[micky]

Thanks a lot for this information.

I'm saving the files you posted, and the links, for next time.

I might be able to do that.

Fortunately it wasn't needed this time. you probably saw that it just needed to be reset. I don't know what happened to make it stop working at 0.5W output.

I don't even know when it happened because when the radio didn't get the signal, I would think, Well maybe the computer is not playing anything, and it took at least a week before I went from one room to the other to be sure. I don't remember any power failures, plus there had been short power failures before that didn't interfere with the xmitter working right.

LOL. Good to hear. Maybe mine will last 10+ years also. It works for a radio in every room and outside, and even in the car parked outside, if it's something I don't want to miss. .

[micky]

These things take time.

Yes. I used to clean dirty tv tuners, when they were mechanical. I've replaced a flyback transformer, diodes, and a bunch of other things I forget.

Since I was 9 years old, although all I had then was a wood-burning iron.

At least 6 of them.