Weird things with lm3886 (brainGT-kit)

michielbeijer · 11th June 2005, 11:04 PM

I just finished (at least that's what I thought I did..) an lm3886 BrianGT kit, but when I powered up I measured some strange values.
First of all, the power supply board makes 28VDC from 22VAC. Not exactly the 1.4 factor I was expecting.
Next, when I measured the DC offset, it was huge: about 1.6V on one channel and 1.7V on the other and the chips get very hot after running for some minutes without any load.

Any advice?

sss · 11th June 2005, 11:12 PM

something is wring with your connections , dont power it up again u will burn the chip , show some pics if u can

michielbeijer · 12th June 2005, 07:21 AM

Sorry, already took it apart. I've had it with those really stiff solid core silverized-copper (?) wires. Had to solder the - hard to reach - connections with the pcb's mounted in the case, that was just asking for bad connections.. Now I'll give it a go with some multi stranded wire and report back when I'm finished.

michielbeijer · 12th June 2005, 10:07 AM

Done! Now with DC offset 0.5 and 0.3 mV (not accounting for deviation of my 15 euro multimeter

). There was probably some shortage going on

cozycactus · 14th January 2007, 03:58 PM

sss
hi. where do you find electronic parts in haifa for diy?

11th June 2005, 11:04 PM	#1
michielbeijer diyAudio Member Join Date: Mar 2005 Location: The Hague, the Netherlands	Weird things with lm3886 (brainGT-kit) I just finished (at least that's what I thought I did..) an lm3886 BrianGT kit, but when I powered up I measured some strange values. First of all, the power supply board makes 28VDC from 22VAC. Not exactly the 1.4 factor I was expecting. Next, when I measured the DC offset, it was huge: about 1.6V on one channel and 1.7V on the other and the chips get very hot after running for some minutes without any load. Any advice?

11th June 2005, 11:12 PM	#2
sss diyAudio Member Join Date: Jul 2003 Location: Israel , haifa	something is wring with your connections , dont power it up again u will burn the chip , show some pics if u can __________________ if you are not living on the edge you are taking too much space

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12th June 2005, 07:21 AM	#3
michielbeijer diyAudio Member Join Date: Mar 2005 Location: The Hague, the Netherlands	Sorry, already took it apart. I've had it with those really stiff solid core silverized-copper (?) wires. Had to solder the - hard to reach - connections with the pcb's mounted in the case, that was just asking for bad connections.. Now I'll give it a go with some multi stranded wire and report back when I'm finished.

12th June 2005, 10:07 AM	#4
michielbeijer diyAudio Member Join Date: Mar 2005 Location: The Hague, the Netherlands	Done! Now with DC offset 0.5 and 0.3 mV (not accounting for deviation of my 15 euro multimeter ). There was probably some shortage going on

14th January 2007, 03:58 PM	#5
cozycactus diyAudio Member Join Date: Feb 2004 Location: haifa	sss hi. where do you find electronic parts in haifa for diy?

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