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Low audio

 

I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

 

Hi Mike,

There were some units that had bad solder connections on one of the surface mount chips - I think it was the audio amplifier.? I would open it up to check.

Before you open the SO2R Box remove the speed pot knob and the nut that holds it to the case.? If you don't you will damage the pot.

Once you have it open, connect it up and try it.? While you are listening to the audio press on the leads of the audio amplifier (the smaller surface mount chip) with an insulated tool - a toothpick would work.? If the audio level changes then you have a bad solder connection.

??? Paul


On Tue, Dec 17, 2024 at 4:07?PM Mike W9RE via <mjwetzel=[email protected]> wrote:
I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

 

Mike

The original unit used 2502-4 ICs to do the keying and PTT.? We replaced it with
a TLP442 or similar to improve keying with Icom rigs.

I may have some in the shack- I'll look later today.

Dennis W1UE


On Tue, Dec 17, 2024 at 4:31?PM Paul Young via <k1xm=[email protected]> wrote:
Hi Mike,

There were some units that had bad solder connections on one of the surface mount chips - I think it was the audio amplifier.? I would open it up to check.

Before you open the SO2R Box remove the speed pot knob and the nut that holds it to the case.? If you don't you will damage the pot.

Once you have it open, connect it up and try it.? While you are listening to the audio press on the leads of the audio amplifier (the smaller surface mount chip) with an insulated tool - a toothpick would work.? If the audio level changes then you have a bad solder connection.

??? Paul

On Tue, Dec 17, 2024 at 4:07?PM Mike W9RE via <mjwetzel=[email protected]> wrote:
I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

 

Dennis,
?
Thanks much.? Right now I am not using Icom rigs but I remember that to a slight extent.? I tried pushing on the audio IC and no improvement as Paul suggested.? Going to set up an audio generator and a scope to try and trace the low audio down.
?
Tnx again,
?
Mike W9RE

On 12/18/2024 7:54 AM EST Dennis W1UE via groups.io <egan.dennis88@...> wrote:
?
?
Mike
?
The original unit used 2502-4 ICs to do the keying and PTT.? We replaced it with
a TLP442 or similar to improve keying with Icom rigs.
?
I may have some in the shack- I'll look later today.

Dennis W1UE
?

On Tue, Dec 17, 2024 at 4:31?PM Paul Young via <k1xm=[email protected]> wrote:
Hi Mike,
?
There were some units that had bad solder connections on one of the surface mount chips - I think it was the audio amplifier.? I would open it up to check.
?
Before you open the SO2R Box remove the speed pot knob and the nut that holds it to the case.? If you don't you will damage the pot.
?
Once you have it open, connect it up and try it.? While you are listening to the audio press on the leads of the audio amplifier (the smaller surface mount chip) with an insulated tool - a toothpick would work.? If the audio level changes then you have a bad solder connection.
?
??? Paul

On Tue, Dec 17, 2024 at 4:07?PM Mike W9RE via <mjwetzel=[email protected]> wrote:
I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

?

?

?

?
 

Update on Low audio:
?
From my good friend WD8DSB:
Today Mike (W9RE) and I did some troubleshooting on a YCCC SO2R box at Mike’s and found we had lost 5 Vdc on pins 11 and 15 on the MAX9722A but we had 5Vdc on pins 2 and 3. We then did continuity checks and saw something like 3 Meg Ohms between pin 2 and 15 as an example. We decided we must have had a broken trace so we installed a jumper between C104 and C107 pins that normally have 5Vdc to reestablish 5 Vdc on pins 11 and 15 and this fixed the original problem of no audio output.
?
BTW my box has a white DIP for U3 where my spare (just repaired box) has a black DIP for U3.? I am not using Icom rigs right now but should I replace it anyway?? If so what part number should I order?
?
Thanks,
?
Mike W9RE

On 12/17/2024 4:07 PM EST Mike Wetzel <mjwetzel@...> wrote:
?
?
I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

 

Mike

The voltage loss is due to a bad via on the board.? You jumpers it the same way that I’ve done it.

The old part number for that IC is a 2502-4.? The revised part number is a TLP542 or similar.? I’ve used several different ICs of that same numbering range.? I can look tomorrow- I may have one in the garage I can send you.

Dennis W1UE


On Thu, Dec 26, 2024 at 18:55 Mike W9RE via <mjwetzel=[email protected]> wrote:
Update on Low audio:
?
From my good friend WD8DSB:
Today Mike (W9RE) and I did some troubleshooting on a YCCC SO2R box at Mike’s and found we had lost 5 Vdc on pins 11 and 15 on the MAX9722A but we had 5Vdc on pins 2 and 3. We then did continuity checks and saw something like 3 Meg Ohms between pin 2 and 15 as an example. We decided we must have had a broken trace so we installed a jumper between C104 and C107 pins that normally have 5Vdc to reestablish 5 Vdc on pins 11 and 15 and this fixed the original problem of no audio output.
?
BTW my box has a white DIP for U3 where my spare (just repaired box) has a black DIP for U3.? I am not using Icom rigs right now but should I replace it anyway?? If so what part number should I order?
?
Thanks,
?
Mike W9RE
On 12/17/2024 4:07 PM EST Mike Wetzel <mjwetzel@...> wrote:
?
?
I obtained? a spare (backup) SO2R Box+ and comparing it to my original unit I notice that the audio is say a good 6db lower when listening to radio 1 when plugged into either channel 1 or channel 2.? This is only with the radio plugged into either DIN,? 12Vdc and audio out plugged in and of course flipping the rx switch.
?
Any things I should check or buy for replacing??
?
Paul was there a chip that was universally replaced in the original buy?? I think the vintage of both units is the same.? Seems like I remember something about a green or white device that should be replaced (updated)?
?
Tnx,
?
Mike W9RE

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