Mini3 not working
Aug 30, 2010 at 1:01 PM Thread Starter Post #1 of 35

midoo1990

Headphoneus Supremus
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I just finished my first DIY attempt and I did the initial check up and everything seems fine as on amb check list,
But the problem is the two LEDs are not working and no light from them.also when I put the board with the battery in the case it stuck
and when I tried bringing it out,there were some small sparklings
between the back of the board and the case whenever I move it.

I didn't try it with a source because I am afraid to connect my jh13 to it
and damage.
Any ideas?
 
Aug 30, 2010 at 1:39 PM Post #2 of 35
LEDs are polarized, did you put them in the right way?
Run through the initial checks again to verify that you did not damage anything.  The amp either passes the tests or it doesn't.  "Seems fine" is not very reassuring...
 
Aug 30, 2010 at 2:04 PM Post #3 of 35
i put the led's taller leg where there is a line on the pcb,thats right?
 the current check is reading 18ma and not 25 .also the u4 pin4 and IG are not reading anything.
 
Aug 30, 2010 at 2:13 PM Post #4 of 35


Quote:
i put the led's taller leg where there is a line on the pcb,thats right?

Wrong (most of the time, anyway -- the longer lead is usually anode, but the board marking is cathode).
 
Quote:
i am running the check again  and interestingly,the u4 pin 4 and IG are not reading anything while before the y were.

Resistance reading?  As long as it's not "shorted" then it's good.
 
Quote:
also the current check is reading 18ma and not 25 .

A bit low, but 2mA could be attributed to the LED, which is still a bit low.
 
The critical tests are the rail splitter check and the output DC offset on all 3 channels.  If those are good then it's safe to plug in your headphones.
 
Aug 30, 2010 at 2:27 PM Post #5 of 35
rail splitter check and DC offset passed the test.i am gonna try it now and then change the leds.
 
Aug 30, 2010 at 2:41 PM Post #6 of 35
its working! there is a massive static sound but its because of my crappy 3.5 computer cable as whenever i wiggle it,it cuts sound.i will get another one now and report back tomorrow.
thank you Mr.Ti for all your help in this past month,i will ask you again surely after a couple of days when i finish my gamma2.
 
Aug 30, 2010 at 6:53 PM Post #7 of 35
Well,I don't think I will wait a couple of days LOL:) it's not working.
I got s new cable and I used my jh13 instead of ibuds and the volume
Is very low even when the knob is all the way up.also there is a big static
and when the bass hits,there is a distortion.

Any ideas on what's wrong?
 
Sep 1, 2010 at 6:01 AM Post #10 of 35
so i charged the battery again yesterday and left it all day and i tried the mini3 again this morning and still the same results.Big static sound,very low volume and distortion.
i reversed the leds so they are working now.i also did the battery check again and it is reading this time 17ma.
i can take pics if recquired.
 
Sep 1, 2010 at 6:25 AM Post #11 of 35
Measure the DC offset of the left and right channels relative to in-ground as you slowly turn up the volume of the amplifier.
What are the high and low readings?
And.. what's the DC offset of the ground channel?
 
Sep 1, 2010 at 2:36 PM Post #14 of 35
The mini3 initial check page sez:
 
 

Output DC offset check

Install the battery, and turn on the amplifier, but set the volume control to its minimum position. Set your multimeter to measure DC mV.
 
  • With the meter's black probe on IG, check the voltages at OG, OL and OR. Use the output jack's sleeve, tip and ring solder pads.
 
 
 
I'm asking you to do the same steps but measure the offset of the left right and channels while slowly rotating turning the volume of the amplifier up and to report the results.
 
Sep 1, 2010 at 4:12 PM Post #15 of 35
ok. OG is the only one reading with IG. it is reading 2.5mV in any volume position.
OL and OR are not reading anything except 1 at the left part of the screen(i am using manual ranging multimeter) on any volume.
 

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