Midland 3001 quiet audio or no audio help required

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original45
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Midland 3001 quiet audio or no audio help required

Post by original45 » 07 May 2018, 13:53

Picked up a really nice condition Midland 3001 complete with mic and bracket .
The original mic will key up however has no audio.
Tried waggling wires nothing .
Replaced mic with a cobra mic wired cybernet ,this time has audio tx but its quiet.replaced this for a York mic and audio is slightly louder but still a little low.output is 4watts.


Wiring in mic looks good.

I'm only guessing but could this be a dirty or dry PTT switch in original mic no audio ?.
Secondly can anyone confirm thethe position or number of the tx audio volume pot so I can try and ajust it back and then up ,see if it makes a difference.

If you suspect fault elsewhere please advice me better. Thank you .

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The Collector
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Re: Midland 3001 quiet audio or no audio help required

Post by The Collector » 07 May 2018, 15:14

Put an accurate little scratch on the outer ring of the trimmers adjacent to the dimple as you test them one at a time. If it's not the right one for the audio, you can then put it back to its original position.
Try from the middle of the board outwards ;)

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Re: Midland 3001 quiet audio or no audio help required

Post by sickboy » 07 May 2018, 15:36

RV105 should be the FM Deviation
Embrace your inner muppet !

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Re: Midland 3001 quiet audio or no audio help required

Post by original45 » 07 May 2018, 20:15

Thank you for the info ,will have a go at increasing tx audio in the week hopefully.

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Re: Midland 3001 quiet audio or no audio help required

Post by original45 » 08 May 2018, 13:55

Rv 105 was correct and once I had sprayed with contact cleaner and rotated pot clockwise audio output was improved .
As for the original mic ,it has me stumped.
With a test meter I checked for continuity in the plug wires to ptt all fine.
Tested ptt to mic speeker fine.
Tested each side of the ptt and noted that the furthest two pins yellow one side and red other make a circuit without ptt being pressed ? Not sure if this is the fault or normal .
The others only work when you press the ptt.

I can only guess the ptt is faulty or maybe the speeker has failed.
Pitty as the Midland mic looks as clean as the radio.
Any further suggestions on identifying the Mic fault would be much appreciated
Thank you for your excellent advices so far .

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Re: Midland 3001 quiet audio or no audio help required

Post by cubwolf » 08 May 2018, 16:17

You should have 600 ohms between pin 1 and 2 on the mic plug with the mic keyed.
Chances are the mic element has failed.
Its quite common on the blue midland mics

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Re: Midland 3001 quiet audio or no audio help required

Post by Mudslinger » 08 May 2018, 17:55

I have had a couple where the element has seized up internally due to corrosion.

They usually meter out ok, but as the moving part cannot move you get no audio.

President and Midlands seem worse for this. The only solution is a replacement element, or don't dribble into the mic in the first place...
Mudslinger - Simon
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original45
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Re: Midland 3001 quiet audio or no audio help required

Post by original45 » 08 May 2018, 18:28

Will test ohm as soon as I'm able .I'm def dribbling at the moment literally just snapped my upper front tooth in half.

Grrr

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Re: Midland 3001 quiet audio or no audio help required

Post by The Collector » 09 May 2018, 17:24

original45 wrote:
08 May 2018, 18:28
Will test ohm as soon as I'm able .I'm def dribbling at the moment literally just snapped my upper front tooth in half.

Grrr
I've told you before, don't strip the insulation off wires like that! ;)

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Re: Midland 3001 quiet audio or no audio help required

Post by original45 » 09 May 2018, 18:30

Wasn't the insulation this time but a rather juicy but costly piece of Kentucky fried rat .
Dentist tomorrow.
I think I just kissed good by to my ssb anytime soon.

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