760 xlt sound problem

[760xlt]

Hello, i have problem with the audio on my 760xlt.
I have no sound from the squlsch/reciver, but the beep from the buttoms working.
I hope anyone can help me.

thanks

 

[hai_akeeba]

Plug an external speaker in to the rear jack. If you get audio there, it is most likely the internal speaker. I had a speaker go on a early 760(rca antenna jack). If speaker, any local radio shop can repair. If no audio, then it probably is the volume/squelch control.

 

[Al42]

Plug an external speaker in to the rear jack. If you get audio there, it is most likely the internal speaker.

What's making the beep if the speaker's gone?

If no audio, then it probably is the volume/squelch control.

Or anything else in the audio section from the detector to the output stage.

 

[northzone]

If the beep from the button press is working it is NOT a speaker problem.

 

[LarrySC]

I think there is a 4PIN Quad audio chip in that radio. Not hard to replace if you have a good solder sucker.

 

[pro92b]

The audio chip is a TDA1905 which has been used in many scanners. If it really is bad, the best plan is to cut all the pins and then unsolder them one at a time. Clean the holes with solder wick and install a new chip.

The symptoms don't necessarily indicate a bad audio chip however. More troubleshooting is needed before blindly replacing parts.

 

[760xlt]

Hello and thanks for all answers, here is some more info

Then i turn the radio on, i have sound in maby one minutes.
The sound disapper first on high freq., the lower freqs have sound longer.
Ihave try to use cold spray, but idont find anything...

 

[pro92b]

The TDA1905 audio chip is IC5. There should be four cylindrical electrolytic capacitors near IC5 as listed below.

C61 10uF 16V
C62 1uF 50V
C63 220uF 10V
C64 47uF 25V (old version with Mot antenna jack)
C64 100uF 25V (new version with BNC antenna jack)

For real troubleshooting you'd need an oscilloscope, but you can try replacing all four capacitors. Use 100uF 25V for C64 regardless which version of the radio you have.

 

[760xlt]

Hello.
I have try to replace the four capacitors & the TDA1905.
But the problem is the same...

some more idea for me?

Thanks

 

[Al42]

Try your cold spray on capacitors, resistors and the IC. If it's frequency related (you did mean high and low audio frequencies, right? Not high and low scanning frequencies?) it's almost definitely a capacitor, an RC circuit or the IC.

 

[760xlt]

Hello again

Al42: i mean high scanning frequencies.

Now I have got sounds in the radio
I have taken away Q7(2SD1676), and now has I sounds all the time. But now has I a new problem, the sound is not good. the is unclear. The roars and lets poorly.
Some as has advice on what the can to last?