No modulation on Turner JM+2/U

[Dark Star]

Hi everyone. I am trying to revive an old Turner JM+2/U and am getting very little modulation out of it. This mic was hardly used and appears to be in excellant shape but there's something not right. I've checked and have good grounding to foil throughout and up to the switch and I am getting 7v to pin one on switch when keyed up. I get some modulation for several seconds and then it dissipates to almost nothing. Has anyone experienced this with this mic?

 

[357magnum]

Your sure the battery is good ? Almost sounds like it's going dead under load ? I use that mic & make my battery by stacking watch battery's together & use shrink tubing . Iv'e used electrical tape before but kind of a PIA .

 

[Dark Star]

Yes I did the same thing. Five 357 watch batteries stacked is what I'm using. The batteries are rated at1.5V reach but I'm getting exactly 8V when assembled. I did find the original 7V battery for sale online but it hasn't come in the mail yet. Maybe it's my homemade battery?

 

[357magnum]

I never have a problem w/ my home made battery's , but I learned one thing Don't buy those cheap ones off Ebay ! They don't last or store well . Now I just buy Energizer or Duracell . The ones made for the Mic are a little pricey , but you know that already . 73 & God Bless , Leo BTW , Welcome to the forum !

 

[Dark Star]

Thanks Leo, I'm using Duracell 357s bought locally so they are fresh and strong. Trying to avoid sending it out for repair but it looks like I'm heading in that direction . 73

 

[Woody-202]

Hi everyone. I am trying to revive an old Turner JM+2/U and am getting very little modulation out of it. This mic was hardly used and appears to be in excellant shape but there's something not right. I've checked and have good grounding to foil throughout and up to the switch and I am getting 7v to pin one on switch when keyed up. I get some modulation for several seconds and then it dissipates to almost nothing. Has anyone experienced this with this mic?

Hey Dark Star, which radio is the mic hooked up to?

 

[Dark Star]

I'm running it on a Galaxy DX2517. Wired 1-shield, 2-white, 3-black and 4-red.

 

[357magnum]

Dark , Did you try spraying the PTT Switch w/ Deoxit or any Contact Cleaner ? Does it do it when you Key it up w/ Jumpers on that switch ?

 

[Dark Star]

I did treat the switch with Deoxit Gold even though it appears that this mic was used maybe once just to test it out when it was first purchased back in the day. It literally looks new (except for the horrific battery leak). The contacts were mint but I hit them with it anyway. Magnum, where would I place the jumper?

 

[357magnum]

Dark , Not sure where to place the jumper ? I tend to do things the Red neck way . I have a probe on a 18" wire w/ an Alligator clip on the end . If I did it ( probably not the right way ) I'd clip the clip on one pole on the switch & start poking ! But I'm sure there is a Mic schematic someplace so it's done correctly . PS , I would attempt this trying to key a mic but I don't poke around in radios like that .

 

[Nowurtalkin222]

Is it a 4 wire mic cord? I recently had one of those but I can't remember the wire colors. I assume it's wired for electronic & not relay. They came both ways & ea could easily be adapted. What about the element? Have you tried the mic on another 4 pin cobra type radio (dynamic not condenser)? The "3 black, 4 red" has me wondering at the moment. I thought black on a turner was always the rcv wire which would be pin 4. Maybe that's not the case with that mic? And red is normally the common on turners, but again, maybe not on that mic, esp since if it's a 4 wire (3 conductors + shield) cord it has no common. Usually blue is tx (pin 3) on a turner but again, maybe not on that old mic. Red just doesn't sound right for rcv but I'm prolly mistaken. Another possibility is incorrect internal wiring. That mic came 2 different ways, a J & a JM I believe & I think the difference was setup for E or R switching, but, either one could be easily converted inside for the ither so possibly someone converted it but got it partially wrong. I believe the wiring & schematic are readily available online. What happened to cbtricks? When did they take their site down? Any word I'd coming back? Where is a CD rom available from? I'll look for the wiring... But you need to test that mic on another radio to confirm the mic problem.

 

[Nowurtalkin222]

Is it a 4 wire mic cord? I recently had one of those but I can't remember the wire colors. I assume it's wired for electronic & not relay. They came both ways & ea could easily be adapted. What about the element? Have you tried the mic on another 4 pin cobra type radio (dynamic not condenser)? The "3 black, 4 red" has me wondering at the moment. I thought black on a turner was always the rcv wire which would be pin 4. Maybe that's not the case with that mic? And red is normally the common on turners, but again, maybe not on that mic, esp since if it's a 4 wire (3 conductors + shield) cord it has no common. Usually blue is tx (pin 3) on a turner but again, maybe not on that old mic. Red just doesn't sound right for rcv but I'm prolly mistaken. Another possibility is incorrect internal wiring. That mic came 2 different ways, a J & a JM I believe & I think the difference was setup for E or R switching, but, either one could be easily converted inside for the ither so possibly someone converted it but got it partially wrong. I believe the wiring & schematic are readily available online. What happened to cbtricks? When did they take their site down? Any word I'd coming back? Where is a CD rom available from? I'll look for the wiring... But you need to test that mic on another radio to confirm the mic problem.

.............................
Followup:

Sorry, my mistake, you're right on the wiring. Didn't realize red was rx black tx. That the exact opposite of more modern turner mics that are red = tx & black = tx. I guess also want to make sure no one switched out the ceramic (not as "hot") element for a hotter crystal element since those famously can go bad with poor handling & storage conditions. I realize that's doubtful since you said mic appears almost unused but you never know... the low modulation has to have SOME explanation. My best guess at this juncture would be to check out those old transistors in the amp. I 4get there's one or 2. The schematics are fairly easily available. Good luck & be sure to post the fix if u finger it out

 

[Nowurtalkin222]

Ugh.. that should've said black = tx & red = rcv. Darn auto correct

 

[Dark Star]

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

 

[Nowurtalkin222]

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

I thought that it was strange how the black and red are different than the norm initially myself. I did verify that the mic was correctly wired for electronic switching and it was. Did not check the transistors but checked all the caps and it's definitely the original ceramic cartridge...untouched. I handed this off to somebody with more knowledge and to be quite honest, the right test equipment to get this ol girl talking again. I will post what he finds for informational purposes and thank you guys for trying to help me. God bless and 73

Test test...
Having major trouble using this site... Tried to reply to you but it bounced so I sent a followup & it bounced as well. But at the same time, I find those in my sent folder, so can't tell if you got them or not? Plus, it's almost impossible to use this now. Using a phone & the site is not cooperating or playing nice w/phone. Can't get it to work in portrait or lannscspe and when I try to click on reply bottom, it goes to some other page or something and it also hides my typing on the screen so I can't see what I'm typing. If this sends, it was extremely difficult to get it done & sent. I need to know if you got the other 2 replies, one was a reply and the other was to tell you about the bounced emails. Definitely not working right.