#1 It has come to our attention that the FET transistor, Q1, may have the wrong pinout in a batch that we purchased back in February 2018. The package dimensions, primarily the flat side is on the wrong side Thus the pinout is reversed. Most have been recalled and replaced but there may still be a few that were shipped from February to June that got by us. The symptom is the audio is very weak or non existent.
You can determine this by the following:
1) Noting the background noise with the gain turned up. You should hear a noticeable "sea shell" noise even with the antenna disconnected. Another way is to take a resistor lead and short R9, the 4.7 meg resistor. If the noise level comes up much stronger (in receive), the transistor is at fault. The quick fix is to remove Q1 and put it in with the flat side opposite what the white silk screen shows. If not happy with this fix, contact Midway and we will ship you a free replacement.
2) It seems the only ones we've noticed that are packaged wrong have a code on the flat side marked F D316 just above the MPF102 part number. All other FETs shipped with different code markings should work fine. (Example: F B510, M849, 418, 438)
Care should be taken when handling and soldering these devices so static electricity doesn't damage the device. If you need this part immediately any N-Channel junction FET should work such as the 2N5457 or equivalent. Just verify the pinout, specifically the gate.
#2 It has come to our attention that since this legacy design in 1996, the FCC regulations have tightened the harmonic limits from 34 db to 44 db. The original design and what Midway has in the ME+ kits don't quite meet this new regulation. Midway has a fix that will bring the ME+ series into compliance. See Compliance Fix. Also the carrier envelope is too steep and may cause off channel chirping. A 4U7 capacitor across the base of Q3 will bring this into compliance.