Turner Super Sidekick issue

[Greg T]

Good deal, I suspect that 1/4 watt audio amp IC is faulty and generating noise, but that goofy looking bugger might be hard to find. I bet that transistor is there to impedance match the element to the amplifier IC, it could generate noise and would be easier to find a sub so I would start there.

Edited to add, a quick giggle search turned up an eBay listing for a lot of 4, kinda pricey.

https://ebay.io/m/t1qSrs

Mouser and digi have the transistor...

I just noticed that my plus threes are doing the same thing but extremely quietly. I get up with extreme feedback long before it makes a difference, and no one can hear it over the air. But those bikes have awesome gain, and this super sidekick doesn't get enough gain to overcome that little hiss. I got a feeling that if I can get the proper output gain out of that sidekick, I won't have to turn it up as far so the noise won't be Audible. So, I'm going to try to find that chip and the transistor. As long as I have to pull the board out, I may as well replace both of them. Thanks!

 

[Cable Guy]

I just noticed that my plus threes are doing the same thing but extremely quietly. I get up with extreme feedback long before it makes a difference, and no one can hear it over the air. But those bikes have awesome gain, and this super sidekick doesn't get enough gain to overcome that little hiss. I got a feeling that if I can get the proper output gain out of that sidekick, I won't have to turn it up as far so the noise won't be Audible. So, I'm going to try to find that chip and the transistor. As long as I have to pull the board out, I may as well replace both of them. Thanks!

Great idea, and also consider ambient noise and emf in the room. I have a friend who loves his d104, and insists on keying it up at arms length and talk at it. In order to get the gain he needs, he has to turn up the d104, but at that point he's now picking up the air conditioner a room away, the tv next door, the street traffic, Cinemax, and the ISS floating above. Just an idea to consider.

 

[Greg T]

Great idea, and also consider ambient noise and emf in the room. I have a friend who loves his d104, and insists on keying it up at arms length and talk at it. In order to get the gain he needs, he has to turn up the d104, but at that point he's now picking up the air conditioner a room away, the tv next door, the street traffic, Cinemax, and the ISS floating above. Just an idea to consider.

Just for the hell of it I ran all the info into AI. Everything I've experienced and done so far. It asked for pics of both sides of the board so I uploaded them. AI says not to replace the audio chip because according to me test procedures it should be okay. The reason is that if I increase the gain control, the noise gets louder which means it's amplifying it;s own noise. That's good. AI is telling me that the most likely problem is a weak element, forcing me to turn up the gain which is increasing the noise. So, I plugged up a plus three and made a quick test. Sure enough, the4 noise gets loud out of the plus three if I disconnect the element and turn up the gain. Apparently, all the turners are noisy, but you can't hear them because they overpower the noise. Also, AI told me there are replacement chips out there that are also obsolete, but there is a way to convert to an 8 pin chip that is much lower in noise and has more freq response. When AI told me I'd have to rewire a couple of things or make a addon board, I told it it was mistaking me for a technician. AI laughed at me and apologized. Anyhow, seems kinda like it makes sense with it being a weak element. After checking, I see it's already been replaced.

 

[Cable Guy]

Just for the hell of it I ran all the info into AI. Everything I've experienced and done so far. It asked for pics of both sides of the board so I uploaded them. AI says not to replace the audio chip because according to me test procedures it should be okay. The reason is that if I increase the gain control, the noise gets louder which means it's amplifying it;s own noise. That's good. AI is telling me that the most likely problem is a weak element, forcing me to turn up the gain which is increasing the noise. So, I plugged up a plus three and made a quick test. Sure enough, the4 noise gets loud out of the plus three if I disconnect the element and turn up the gain. Apparently, all the turners are noisy, but you can't hear them because they overpower the noise. Also, AI told me there are replacement chips out there that are also obsolete, but there is a way to convert to an 8 pin chip that is much lower in noise and has more freq response. When AI told me I'd have to rewire a couple of things or make a addon board, I told it it was mistaking me for a technician. AI laughed at me and apologized. Anyhow, seems kinda like it makes sense with it being a weak element. After checking, I see it's already been replaced.

I'm always leary of ai expertise, ask my wife about ai incorrectly identifying venomous snakes as harmless, and a swooshing noise doesn't click in my mind as being an element issue. Increased gain will increase noise, but I have never seen a weak element create a swooshing kind of noise, mostly continuous hum and static. I'm afraid changing the amp circuit will also change the sound, and being the collector you are, you would want it stock as it came from the factory. If you do try another element, let us know how it goes.

 

[Cable Guy]

I'm always leary of ai expertise, ask my wife about ai incorrectly identifying venomous snakes as harmless, and a swooshing noise doesn't click in my mind as being an element issue. Increased gain will increase noise, but I have never seen a weak element create a swooshing kind of noise, mostly continuous hum and static. I'm afraid changing the amp circuit will also change the sound, and being the collector you are, you would want it stock as it came from the factory. If you do try another element, let us know how it goes.

I went back to the op and listened to your video with volume max, it sounds like static for a second, not a swoosh but static that fades out some. It may be too much gain, without passing some tones through it and measuring the output, I can only speculate. What level is the mic turned up to in that video?

 

[Greg T]

I went back to the op and listened to your video with volume max, it sounds like static for a second, not a swoosh but static that fades out some. It may be too much gain, without passing some tones through it and measuring the output, I can only speculate. What level is the mic turned up to in that video?

I turned it up to the point where my voice would be sufficient to transmit. Now, I've run Turner microphones since the 1970s and I've only ever had to turn them up to the 9:00 position to get absolutely perfect and strong modulation. To get proper modulation out of this sidekick I need to turn it to at least 2 to 3:00 position at which point the noise is unbearable and comes through my transmission. I wasn't saying that the element was causing the noise, but rather, the element was so weak that I had to turn it up so that the internal noise of the microphone was coming through the transmission. I verified the internal noise from the Turners by testing two of my plus three mics that are working perfectly. I disconnected the elements and turn the gain up and got the exact same noise. But again, I only have to run them at the 8:00 position so the noise is not audible.

 

[nomadradio]

Every year that goes by the MFC chips will get pricier. Kinda like 8950 tubes, but a bit less brutal. Nobody ever second-sourced those oddball chips. Only came from Motorola.

73

 

[Greg T]

Every year that goes by the MFC chips will get pricier. Kinda like 8950 tubes, but a bit less brutal. Nobody ever second-sourced those oddball chips. Only came from Motorola.

73

I found this: MFC4000B = ECG752 / NTE752.

 

[VMC]

Here's the datasheet. Should be pretty easy to find a 21st century solution

 

[ClaimJumper]

I have no input on what the problem might be, but if you want to onesie twosie parts, you can do that at digikey. Oh and also, just a heads up. If you're going to replace that mic element I might have a stock one soon. It might be the same as a sidekick 100.? I'm going to do the electret conversion on my 100. If you want to wait a couple weeks I'll cut you a good deal on what comes out of my 100.

 

[Greg T]

I have no input on what the problem might be, but if you want to onesie twosie parts, you can do that at digikey. Oh and also, just a heads up. If you're going to replace that mic element I might have a stock one soon. It might be the same as a sidekick 100.? I'm going to do the electret conversion on my 100. If you want to wait a couple weeks I'll cut you a good deal on what comes out of my 100.

I was chatting with CHATgpt today about it and was given some tests to make. I was told that the SSK dynamic element was supposed to be between 200 to 500 ohms. If I got an open reading, the element was either electret, ceramic or crystal. Well, it looks brand new and it's open. I'm guessing someone changed out the element and put the wrong one in. Also, I see that mine DOES have the impedance matching xformer on the board. So I am baffled now. BUT, I would be interested in those carts. Lemme know what you want. Hopefully, they work as intended? If you could make sure they are 200 to 500 ohm?

 

[ClaimJumper]

Okay. Here's some Hardware info.. the screw that holds the mic element housing together is 5/32 8-32 thread by 1 inch. I'm replacing mine cuz the drill bit hit it. I didn't realize the disc was so thin and easy to drill through. I'm going to reuse the disk I have with the hole drilled in it however you can get a 3/16 number 10 washer that's exactly the same size. Once the washer is in I'm going to cover the hole with foil tape. Cut it the same size as the disc . Maybe an exacto knife would be best . They use it in heat and air applications, it can be bought at any hardware store. I happen to have some so I don't need to buy the roll. It's very Chrome looking. You can also use some googly eyes or a silver star. LOL