Looking for the pin color coded wiring of a Diesel 4-3 Noise Cancelling 4 wire mic to a 5 pin Uniden Washington. Any info would be appreciated. Mic wire colors are black, red, yellow and shield. Thanks Dan
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Wiring a Diesel 4-3 Noise Cancelling 4 Wire Mic to a Uniden Washington 5 Pin
- Thread starter danmcclain
- Start date
Well, to start with, you gotta make a decision about the arithmetic problem. Five doesn't equal four.
The 5-pin socket has two ground pins. One for audio only, and one for the transmit/receive switching circuits. This serves to keep noises and feedback out of the mike amplifier by having its own ground connection. Since only audio currents travel through it, no additional current flow shares this wire.
A radio with a 4-pin mike socket has only one ground pin, and it shares the switching currents with the audio currents on that single ground pin.
You're presented with three possibilities.
Connect your one ground wire to pin 2, and ignore pin 4.
Connect it only to pin 4 and ignore pin 2.
Or connect a jumper wire across pins 2 and 4, then connect your ground wire to it.
The first choice will tend to produce a feedback squeal from the receiver speaker when the volume is turned up.
The second one favors feedback squeal on transmit.
The third option tends to balance the squeal behavior between transmit and receive, both.
There is a wild card in the deck, though. Manufacturing tolerances and component aging will make the feedback issues impossible to predict. One radio will squeal with the mike gain just cracked, and the next one won't misbehave at all.
I have never seen an analysis of the radio that explains this variation. Even if the radio's mileage was a way to predict it, there's no odometer to read.
You can use a relay to switch the transmit/receive wires and connect it to pin 4. Now pin 2 will have only audio current on it.
Just one problem. The relay will turn the speaker back on too quickly when you unkey, causing a "POP" sound from the speaker when you release the mike.
We developed an adapter that had two relays on it. One for transmit, and one the would turn on the speaker only after a short delay when you unkey. Fixed the "POP" problem, and allowed you to use a 5-tone roger beep. They don't come with a relay.
Just one problem with this 4-pin adapter. It was built on the back of a 4-pin mike socket, just went in place of the factory mike socket. The circuit board had to be small to fit in that space. The relays we chose were small enough, but turned out to be wimpy. The receive speaker would begin to cut out after a few weeks of regular use on some of them.
Can't make a buck selling things you can't rely on, so it never reached the status of "product for sale".
As for the wire colors on the mike cord, that's only informative if you have the factory manual for the mike. Every manufacturer uses a different color scheme.
I will hazard an educated guess that black is receive, red is transmit and yellow is audio. The shield, naturally is ground.
Yellow would go to pin 1,
Black to pin 3,
Red to pin 5.
And the shield goes to eeny-meeny-miny pin 2, or 4 or both.
73
The 5-pin socket has two ground pins. One for audio only, and one for the transmit/receive switching circuits. This serves to keep noises and feedback out of the mike amplifier by having its own ground connection. Since only audio currents travel through it, no additional current flow shares this wire.
A radio with a 4-pin mike socket has only one ground pin, and it shares the switching currents with the audio currents on that single ground pin.
You're presented with three possibilities.
Connect your one ground wire to pin 2, and ignore pin 4.
Connect it only to pin 4 and ignore pin 2.
Or connect a jumper wire across pins 2 and 4, then connect your ground wire to it.
The first choice will tend to produce a feedback squeal from the receiver speaker when the volume is turned up.
The second one favors feedback squeal on transmit.
The third option tends to balance the squeal behavior between transmit and receive, both.
There is a wild card in the deck, though. Manufacturing tolerances and component aging will make the feedback issues impossible to predict. One radio will squeal with the mike gain just cracked, and the next one won't misbehave at all.
I have never seen an analysis of the radio that explains this variation. Even if the radio's mileage was a way to predict it, there's no odometer to read.
You can use a relay to switch the transmit/receive wires and connect it to pin 4. Now pin 2 will have only audio current on it.
Just one problem. The relay will turn the speaker back on too quickly when you unkey, causing a "POP" sound from the speaker when you release the mike.
We developed an adapter that had two relays on it. One for transmit, and one the would turn on the speaker only after a short delay when you unkey. Fixed the "POP" problem, and allowed you to use a 5-tone roger beep. They don't come with a relay.
Just one problem with this 4-pin adapter. It was built on the back of a 4-pin mike socket, just went in place of the factory mike socket. The circuit board had to be small to fit in that space. The relays we chose were small enough, but turned out to be wimpy. The receive speaker would begin to cut out after a few weeks of regular use on some of them.
Can't make a buck selling things you can't rely on, so it never reached the status of "product for sale".
As for the wire colors on the mike cord, that's only informative if you have the factory manual for the mike. Every manufacturer uses a different color scheme.
I will hazard an educated guess that black is receive, red is transmit and yellow is audio. The shield, naturally is ground.
Yellow would go to pin 1,
Black to pin 3,
Red to pin 5.
And the shield goes to eeny-meeny-miny pin 2, or 4 or both.
73
Here's what I do and take it or leave it.
You have only 3-wire w shield?
But the original had 4-wire w shield?
Can you use the old mic wire?
No?
Then you'll have to commit to a change AT THE SOCKET the mic plugs into - else once this mess is over - you'll have to "revert" back to OEM.
Is it hard? No.
What then? You make a switch of the PIN 2 wire - you no longer use PIN 2 - it's left open - leave 3, 4 and 5 - Pin 4 Now becomes your Pin 2 - with a catch...
You have to pull the socket, (you can try to do this with it mounted - a little tricky with the loom there. And on that board, then just "short" Pin 2 and 4 together - AT THE PLUG SIDE (Where the pins meet the MIC BOARD - the board exit leads get left alone. They will go to their respective spots.
Why?
Here schematically...
Note:
Socket 2 in the HANDSET is the Shield.
Socket 4 in the HANDSET in Board Ground.
Pin 2 at the MIC SOCKET BOARD - contains the Ferrite choke needed for AUDIO ground for the MIC - as SHIELD.
Pin 3 is Speaker Return
Pin 4 is Board ground.
Pin 2 on the JACK (actual plug end) transfers over SHIELD to a coil / ferrite - jumper to a FOIL board ground - INSIDE the radio - at the MIC SOCKET BOARD.
So, you're taking away Shield from Pin 2 but shorts to Pin 4 - Pin 2 is now same inside electrically in the case of the radio.
Add jumper wire - or bare clipped lead wire of a component. Solder that Wire from Pin 2 at the MIC SOCKET BOARD to Pin 4 at the socket.
The wire that went to Pin 2 - now goes to wire FROM MIC SOCKET BOARD that originally went to 2 - but uses 4 to ground.
Then HANDSET plug wiring - remove Pin 2 SHIELD and place it on PIN4 SHIELD and wire that is board Ground.
Now most people just call it good at this swap - and most of the time this takes care of the 4 - 5 wire - but why the extra step? The Audio Ground is a different trace and goes thru a component that electrically is a dead short to DC - when you simply rewire the 4-wire - shield - you're using Pin 4 - and board ground.
But that is at the Handset.
But at the mic jack - back inside the radio Pin 2 is now open for business, and the first thing it's going to use is the choke, and as Murphy's Law usually works, becomes the antenna nobody wanted and begins a downward spiral of events that also, nobody else wanted...
Why not go to Pin 2 and use its ground instead?
You could, but the CHOKE is a coil a near dead-short at DC but adds a hi-cut filter to the Speaker - by being the RETURN, it chokes off RF, but now makes a bassy mess added to an already narrowed down and filtered mess the output side of the Audio Chip is working through to even get to the speaker.
So that is where pin 4 is used, because the MB3756 requires it to be this way.
Pin 4 is ground - speaker uses it, and so does Mic Pin 5 - which routes to another pin - directly - well? Maybe not DIRECTLY - but it doesn't use a coil - instead it looks at the output of a transistor - which has the other side of it's "Valve action" to Pin 5 of the MB3756 - the valve though, is controlled by Pin 6 a LOCK pin off the MB8719.
Gott'a a lot of Pins there Andy...
Why do it this way?
Deals with Case / Chassis to Board Ground - Pin 5 uses a switch, for a switch - like a AND Gate - This happens when This and That are GOOD - so when the operator keys the Mic, Pin 5 grounds Pin 4 - Pin 3 goes open - stops the speaker - that is at the HANDSET - the now grounded Pin 5 LINE heads off to a Transistor that is set up to look at the PLL's LOCK condition - if good - then can allow ground to reach Pin 5 - but not at TRUE ground potential - just lower voltage - a lower than a threshold setting set up at the MB3756 - so it can toggle one of its pins high (TX MB3756's Pin 8) and another one to Low (Off - MB3756's Pin 6) - why the discrepancy? The Voltage drop across a transistor (remember that Pin 5 of the MB3756 is a sense pin looking for changes to its status as a pin held high internally). The action, when it drops - tells the system to toggle two pins.
Best to do the Pins' 2 to 4 jumper internally at the MIC JACK BOARD and tie (meaning pair) SHIELD on handset to the free switch contact on the DPDT switch...at the HANDSET...like this...
Why did I go thru all of this?
Because of the (ab)user that REFUSES to restore Limiter.
You get kind of tired of the problem - and you can lose your livelihood if you can't make peace with those around you.
In any Uniden 385 board, the limiter engages thru the RX line when the radio is in RX mode - thru D41 and Resistor R98 - when you remove the limiter - RX line can't shut off the MIC line - so any noise in the line from the open mic at Pin 1 now shows up here - and MIXES in with RX audio - no matter what...
Need proof? Turn down the Mic Gain (Dynamike) does your noise disappear?
Remember the old 4-2 Diesel Mics?
They used a DPDT and set up to handle RX/TX toggle separate and provided a means to short the live MIC wire when not used - Realistic did too...
You have only 3-wire w shield?
But the original had 4-wire w shield?
Can you use the old mic wire?
No?
Then you'll have to commit to a change AT THE SOCKET the mic plugs into - else once this mess is over - you'll have to "revert" back to OEM.
Is it hard? No.
What then? You make a switch of the PIN 2 wire - you no longer use PIN 2 - it's left open - leave 3, 4 and 5 - Pin 4 Now becomes your Pin 2 - with a catch...
You have to pull the socket, (you can try to do this with it mounted - a little tricky with the loom there. And on that board, then just "short" Pin 2 and 4 together - AT THE PLUG SIDE (Where the pins meet the MIC BOARD - the board exit leads get left alone. They will go to their respective spots.
Why?
Here schematically...
Note:
Socket 2 in the HANDSET is the Shield.
Socket 4 in the HANDSET in Board Ground.
Pin 2 at the MIC SOCKET BOARD - contains the Ferrite choke needed for AUDIO ground for the MIC - as SHIELD.
Pin 3 is Speaker Return
Pin 4 is Board ground.
Pin 2 on the JACK (actual plug end) transfers over SHIELD to a coil / ferrite - jumper to a FOIL board ground - INSIDE the radio - at the MIC SOCKET BOARD.
So, you're taking away Shield from Pin 2 but shorts to Pin 4 - Pin 2 is now same inside electrically in the case of the radio.
Add jumper wire - or bare clipped lead wire of a component. Solder that Wire from Pin 2 at the MIC SOCKET BOARD to Pin 4 at the socket.
The wire that went to Pin 2 - now goes to wire FROM MIC SOCKET BOARD that originally went to 2 - but uses 4 to ground.
Then HANDSET plug wiring - remove Pin 2 SHIELD and place it on PIN4 SHIELD and wire that is board Ground.
Now most people just call it good at this swap - and most of the time this takes care of the 4 - 5 wire - but why the extra step? The Audio Ground is a different trace and goes thru a component that electrically is a dead short to DC - when you simply rewire the 4-wire - shield - you're using Pin 4 - and board ground.
But that is at the Handset.
But at the mic jack - back inside the radio Pin 2 is now open for business, and the first thing it's going to use is the choke, and as Murphy's Law usually works, becomes the antenna nobody wanted and begins a downward spiral of events that also, nobody else wanted...
Why not go to Pin 2 and use its ground instead?
You could, but the CHOKE is a coil a near dead-short at DC but adds a hi-cut filter to the Speaker - by being the RETURN, it chokes off RF, but now makes a bassy mess added to an already narrowed down and filtered mess the output side of the Audio Chip is working through to even get to the speaker.
- it's why Pin 2 is separate - a place for Audio ground to keep things balanced like any audio system should have, but is a formidable fortress for RF - so those kinds of fields stay out,
So that is where pin 4 is used, because the MB3756 requires it to be this way.
Pin 4 is ground - speaker uses it, and so does Mic Pin 5 - which routes to another pin - directly - well? Maybe not DIRECTLY - but it doesn't use a coil - instead it looks at the output of a transistor - which has the other side of it's "Valve action" to Pin 5 of the MB3756 - the valve though, is controlled by Pin 6 a LOCK pin off the MB8719.
Gott'a a lot of Pins there Andy...
Why do it this way?
Deals with Case / Chassis to Board Ground - Pin 5 uses a switch, for a switch - like a AND Gate - This happens when This and That are GOOD - so when the operator keys the Mic, Pin 5 grounds Pin 4 - Pin 3 goes open - stops the speaker - that is at the HANDSET - the now grounded Pin 5 LINE heads off to a Transistor that is set up to look at the PLL's LOCK condition - if good - then can allow ground to reach Pin 5 - but not at TRUE ground potential - just lower voltage - a lower than a threshold setting set up at the MB3756 - so it can toggle one of its pins high (TX MB3756's Pin 8) and another one to Low (Off - MB3756's Pin 6) - why the discrepancy? The Voltage drop across a transistor (remember that Pin 5 of the MB3756 is a sense pin looking for changes to its status as a pin held high internally). The action, when it drops - tells the system to toggle two pins.
- One goes on, Pin 8 - for TX
- the other goes off, Pin 6 - for RX
- - when that sense system inside the MB3756 sees a change to a higher voltage presence (open line or transistor is now off - High impedance stage transistion) the internal system switches the toggle state back (reverts the condition)
Best to do the Pins' 2 to 4 jumper internally at the MIC JACK BOARD and tie (meaning pair) SHIELD on handset to the free switch contact on the DPDT switch...at the HANDSET...like this...
Why did I go thru all of this?
Because of the (ab)user that REFUSES to restore Limiter.
You get kind of tired of the problem - and you can lose your livelihood if you can't make peace with those around you.
In any Uniden 385 board, the limiter engages thru the RX line when the radio is in RX mode - thru D41 and Resistor R98 - when you remove the limiter - RX line can't shut off the MIC line - so any noise in the line from the open mic at Pin 1 now shows up here - and MIXES in with RX audio - no matter what...
Need proof? Turn down the Mic Gain (Dynamike) does your noise disappear?
- - this is especially true when they've removed R186
Remember the old 4-2 Diesel Mics?
They used a DPDT and set up to handle RX/TX toggle separate and provided a means to short the live MIC wire when not used - Realistic did too...
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