Mike, I don't know how many times that I have a similar problem...except that someone had wanted a particular microphone wired to a particular radio and had problems...no modulation, no transmit, no receive, squeal when the mic is keyed up, etc. So what do they do? They go inside the radio and rewire the entire mic jack from the inside of the radio, adding parts like resistors or diodes or capacitors, etc. I can't tell you the number of times that I have had to go inside a radio and rewire the mic jack from the inside, and then rewire the mic itself to fix the problem...because even though they may have "fixed" the squealing problem, or no transmit or receive...it will work, but you can only turn the mic gain up so far on the radio and/or mic before it starts squealing, or actually keys up by itself or the receive cuts out. Great video to an age old problem that I still get across my desk from time to time. Thanks for the info!!
Hope you have a minute for a tech question. I have a Montgomery Ward 719a that has the 5 pin microphone plug. I recently bought a 4 pin to 5 pin microphone adapter from ebay and it works fine on transmit but when I am in receive mode, if I have the radio volume up to loud I get a slight amount of squeling through the speaker. I don't have talk back and it's only happening in receive. I'm thinking it's a problem with the way the radio has to have a microphone plugged in to receive. It never did this with the stock microphone and I believe it's just due to the adapter. Any suggestions would be great. I'm in Nacogdoches Texas and would really appreciate the help. Thank you
A quick question if I may, are you still repairing radios? I have a Tram D-201A that needs a restoration, it has a gray Chanel selector. Thanks Micheal
Takes me back to 1977, trying to explain to a customer why he needed a 6-wire mike to work on a radio with a 4-pin mike socket. The only explanation that worked was to take a 6-wire version of his older mike and plug it into his radio. "My mike works, yours won't. What else do you need to know?" The explanation about why his SSB radio worked with the 4-wire mike and his AM radio would not just got me blank stares. 73
On another note, if you have a problem with wiring 4 wires, and some people do, you can use a N/O micro switch and just break into the audio wire. Some of those switches made by Cherry fit right in there and a little dab of hot glue works very well.
Would a 4N25 opto-isolator and 810 ohm resistor work in place of the electromechanical relay? The resistor, or course, is for the input LED of the opto. I calculated Rd = (9 - 1.2) / 0.01 = 780. 810 is the next available 5% tolerance resistor size. The trick would be wiring the output side of the opto.
I found if you use a Sharpie and right on top of the old writing and then wipe it off works well. But I'm not sure what it would do for you if it's soaked into that vinyl.
Hi Mike, I saw this radio on eBay for sale awhile back. I have the exact radio telsat 140, I Am trying to wire a Turner expander500 mic , will it work?
RSC Electrical back in the late 60s early 70s, when power Mikes gained popularity was to take a thin piece of copper wire have it in between the coil of the microphone cord ground it on one of the screws on the side of the radio and the other end to one of the screws on the microphone usually took out the squeal so you can fine-adjust the audio short of over modulation etc.
Polarity marks on the top of the case tell you that the flyback diode is built in. No need to add an external diode to catch the flyback pulse when the coil is de-energized. 73
Sir, I am from the Philippines, would it be ok to ask for your email ad? I do have some questions to ask for you are the man to ask because of your excelent knowlege. Thank you very much sir.
Hi my name is i have a 29wxst that has problems it comes on but i,m not really getting any audio and the signal swr not lighting up meter does nothing and all the parts were totally adjusted wrong sorry for long message iust paid to much for the radio maybe you have some advice .the the your channel
+Brandon Mazza First place to start is with a transceiver alignment. It is possible it's so far out of alignment it's causing your problems. If not the alignment procedure makes a good first troubleshooting step to start to isolate problems.