Re: uBitx low signals on the speaker

w7hd.rh <w7hd.rh@...>
 

Here is a fix for the audio chip heating.  It involves a very simple 7806 voltage regulator mounted on the back of the board.

Enjoy,

Ron W7HD


On 03/13/2018 05:45 AM, Arvelino Almeida Junior via Groups.Io wrote:
Hi ubitxer's, I received, I mounted and calibrated my ubitx these days, here in Brazil. And the results:
 
1) Low volume of the signals received in the speaker, being necessary to increase the volume at the maximum for some weak signal.
2) TDA2822 FIC heating when it receives some signal measured around 45º Celsius.
3) When I connect the speaker output to another external amplifier everything is normal.
Mods made:
1) Replacement of the FIC TDA2822 by Av2822P manufacturer Avic (used in pc sound) which is also warming up.
2) Installed socket dil 08 on the board for possible replacement.
No Results
 
Tests:
1) Measurements of the components around the AV2822P. OK
2) Test with 1Khz @ 1.5Vp signal injector at the amplifier input (pin 7) Ok
3) Test with rf generator (strong signal on the speaker) Ok
 
I am believing that the problem may be in the RF step of uBitx.
I'm analyzing
 
73 from Junior

-- 
Ron W7HD - NAQCC#7587 OMISS#9898 KX3#6966 LinuxUser#415320
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