Help reg tpa3116 board

[sarathssca]

Hi ,
I am trying to start break-in process for alpair 7p till I complete it's enclosure as in the attachment. I am using tpa3116 based board powered by dell laptop Power supply and source is from mobile. I am facing below problems:

1. When not connecting the source and only running the board with power supply and speakers, the power supply is stable . But as soon as I am connecting the mobile input to it the power supply is getting off. If I am switching off and on the mains it's coming up and again going off in a moment.

2. When switching on or off the power supply, the speaker is making sudden "dub" sound with cone moving up- down .

Please suggest what could be the problem and how we may resolve it.

 

[badrisuper]

check recommended power supply for this amp and ur dell adapter.

thanks
badri m

 

[sarathssca]

i have checked for any shorts in the connections on the board, at the input , output, power supply inputs on the boards.. all look ok.. no shorts..
but on checking the resistance across the power supply inputs on the board using mulitmeter, it showed around 572 ohms and when reversed the polarity of the multimeter leads it showed open circuit. I think it was showing because a capacitor was connected across Vcc and GND..
Is it expected for a capacitor to show some hundreds of ohms resistance and again show open circuit when measured by reversing the multimeter leads?

 

[sashijoseph]

Is it expected for a capacitor to show some hundreds of ohms resistance and again show open circuit when measured by reversing the multimeter leads?

Maybe there's a series diode to prevent accidental wrong polarity at the supply terminals...hence the open circuit in reverse condition.

It's not clear from the image but there seems to be only two wires in the input cable.
Have you connected all three In-L,In-R and Gnd ?

With so much happening I would immediately remove the Alpairs and hook in some cheap sacrificial speakers till the time the amp behaves more reliably.

 

[jls001]

Regarding the thump at power on/off, is there a terminal for connecting a double throw switch? My 3118 boards have such a terminal. I have connected a switch. Power on sequence is to keep this switch in off position then switch on the main power switch, followed by the said switch. Startup thump is a known issue on some 3116/3118 boards.

 

[sarathssca]

Ya I have a old not so good condition speaker to test .. will be using it till amp looks better ..
Jls001:
Do you have any picture of that switch with the amp ..

 

[jls001]

Jls001:
Do you have any picture of that switch with the amp ..

See the very first pic on the first post of this thread:

http://www.hifivision.com/diy/65258-improving-tpa3118-class-d-amplifier.html

See the text "MUTE" on left hand bottom side of board. You need to fit any toggle switch rated about 5A to break or make the Mute signal. Mute stops the amplifier from sending output to speakers. It's very useful for stopping startup voltage spike from reaching the speakers.

 

[doors666]

Those I believe are quite delicate speakers (atleast the metal cone ones are). get some test woofers from local shops for 100-200 bucks. something goes wrong during your amp testing, it will keep your expensive imported drivers safe.