Red LED will not turn on.
Dead Battery
Typically when the battery dies the LED will no longer turn on and noise will not come out of the speaker. Try replacing the 9-Volt Battery.
Bad Solder Connections
Bad solder connections can be spotted with the naked eye. If this is the problem then you may find some cold welds, which means the solder did not settle right giving it a scuffed look instead of shiny. The other problem could be that a sufficient amount of solder was not added to area of the connection. Using a multimeter, check the voltage across each component. Begin the testing at the positive terminal of the voltage source and systematically check through the circuit until you find a component that has a voltage reading of zero. Try to solder this connection again.
The LED turns on and the speaker makes ambient noise but I cannot receive any radio signals
Bad Solder Connections
The first connection you may want to test is the capacitor labeled "C-22." This capacitor amplifies the radios capacity to receive radio signals. If there is no current flowing through the capacitor then you may want to replace the capacitor or solder the connection again. If the C-22 capacitor is working properly then you may want to systematically check each connection again until you locate a component that has 0 voltage passing through it. Try soldering this connection again. If this does not work then you may have to get a replacement for this component.
crwdns2915084:0crwdne2915084:0
Charlie Riel crwdns2935289:0Charlie Rielcrwdne2935289:0
Community
crwdns2934841:01crwdne2934841:0
crwdns2935297:02crwdne2935297:0
crwdns2944067:012crwdne2944067:0
Catches radio signals, check. Hearable, not a snowball's chance in !&&*.
the117doctor - crwdns2934203:0crwdne2934203:0
Like the censor
the117doctor -
Led light works. No sound and U2 semiconductor becomes very hot after a few second? Suggestions?
David - crwdns2934203:0crwdne2934203:0
I have same issue.
Chris Moore -
You put the U2 in backwards. Probably fried it when it got hot.
Curtis Gilreath - crwdns2934203:0crwdne2934203:0
per https://www.youtube.com/watch?v=lArlPXox...
Varactor D1 is not perfectly automatic.
Adjusting L2, can allow D1 to do its job.
L2 needs an iron core, instead of air core I applied adjustment by inserting a tiny steel screw into the center of L2 inductor. Thus, it increased the inductance ( value of henrys). Machine screw size #6 (.138” dia) and 0.5” total length long.
Now, press yellow button switch S1, wait for tuning.
My board started working. To prevent shorting, please insulate screw with electrical tape or shrink tubing.
Supporting document: https://www.elenco.com/wp-content/upload...
page 12 read “Alignment”.
Stuart Lew - crwdns2934203:0crwdne2934203:0
Right on! Makes sense. Something for my students to try!
Debra Perretta -
rado plays awhile, then the light fades and the radio goes silent. Turn off and then back on and radio plays but led fades again and radio goes silent. In the assembly firs time i fried the u2 chip by getting it backwards. Replaced the chip but now this problem. did I fry something else??
burrowesp - crwdns2934203:0crwdne2934203:0
Red light turns on and plays constant hum. When S button is depressed, sound audible thump noise the loud static. Checked all components and they seem to be fine.
will smith - crwdns2934203:0crwdne2934203:0
My led won’t turn on but my speaker is marking static noses I’m am curintly on test one
dan sauce - crwdns2934203:0crwdne2934203:0
Help pleas :(
dan sauce -
IT IS ALMOST ALWAYS BAD SOLDERING...or polarity mix ups. I have done this project with lots of students. First go through and check for voltage at each solder. Set voltmeter to 9V tough the + terminal on your battery and go through the process...anything with 0 or a solder that is moving around...resolder it.
If you have no sound and no LED, but have V running through the circuit, check the soldering to the on/off switch. I had several bad connections from my students on this...it would also show 0 voltage at the antenna in some instances. The top prong of the on/off switch is in series with the LED D3 and the diode D2 as well as the switches for the stations.
IF you have done everything and have an LED light and fuzz (no stations) check capacitor connection c13...it is under the battery holder so it is hard to test...remove the battery holder and resolder that connection. C13 goes to the 4 loop coil L2 and the IC chip on leg 5 which is the oscillator (see page 5 schematic).
Debra Perretta - crwdns2934203:0crwdne2934203:0