Muffled TX Audio

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Radiofad
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First Name: Kel
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Muffled TX Audio

Postby Radiofad » Sunday 14th Sep 2014, 23:36

Radio Make and Model: President Washington
PCB Number:
PLL Number: upd858
Test gear available: service monitor
Symptoms: muffled tx audio, not bad but noticeable.

What is working: everything

What has been tried: tune, different mic

Did it suddenly happen ?: don't know
Anything else that may be of help?:

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sonoma
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Re: Muffled TX Audio

Postby sonoma » Monday 15th Sep 2014, 6:12

do not know if your problem is the same as mine was, but after I recapped the radio with new electro caps the audio cleared up on mine. my receive was also a little muffled sounding. did mine a little over a year ago and it is still going strong. mine is the 858 PLL also. just remembered on my the bias VR's were also bad and had to replace them and c179 was getting bad. put a 2.2 electro cap in it. factory it is a tantalum cap.

Radiofad
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Posts: 5
Joined: Saturday 4th Apr 2009, 17:07
First Name: Kel
Location: Australia

Re: Muffled TX Audio

Postby Radiofad » Monday 15th Sep 2014, 11:21

Thanks sonoma, have started replacing electros. Will finish it off and let you know how it goes.

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sonoma
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Re: Muffled TX Audio

Postby sonoma » Monday 15th Sep 2014, 18:29

forgot to mention change all the 10 volt caps to 16 plus volt caps. the 10 volt are in the 8 volt circuit and they are just to small. I usually put 25 volt caps back in the 10 volt places to be safe. and make sure the bias voltage will adjust properly after doing the recap. if the bias is too low or too high can cause the tx audio to sound muffled also.

make sure your power supply is maintaining enough voltage to the main board also.


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