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alvin1118

DIY: AMB Lab Mini3

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just finished debugging & repaired a friend's mini3..sorry for keeping the mini3 with me for so so so so long. i hate exam! lol

 

problems are as follow:

  1. Left side no sound
  2. HIGH Voltage Output at Left Channel
after re-solder all soldering points, make sure no cold soldering or short circuit , power up and test.. well, results are the SAME :wacko: no sound no sound!! :doh:

 

alright, last try is to change the OPA AD8397! mini3 is well known in burning OPA. lol :bash:

SOIC OPA not easy to de-solder without proper smd remover tools..traditional method is to apply huge amount of solder on top and bottom of the SOIC, and "try" to remove it by heating up the solder...hm..i'm not good in describing, just REMOVE IT!! wahaha :rclxub:

 

after changing the OPA, measure OR-OL-OG to Gnd, all within recommended range. plug in my senn earbud with mp3 input~~~

 

wow~~it works wonder now!!! :thumbup:

 

This must be referring to my set :P

I'm enjoying it now. Really happy with it and thanks a lot for helping me trouble shoot. I suspected it was the OPA but didn't dare to remove it (after you know what happened heeheehee) I'm still quite amazed that you managed to remove the OPA without any SMT removal kit. Good stuff.

 

I think the OPA must have got burnt when I tried to mount the battery plates. Mounted the plates to the rechargeable battery and then soldered the plates in place. This was advised by the website to get a good fit. But they mentioned that the battery should not have anymore charge. I thought the rechargable battery being new would not have any charge. Looks like I was wrong..

 

Anyway, thanks again. And do let me know when the other set is available.

 

 

 

 

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Use the capacitance setting to measure caps. Can't use DCV to measure capacitance. At least not as I know it.

 

Thanks for the tip, pardon me but what do you set to to measure capacitance? ohm, VDC, etc?

 

I'm using the multimeter below btw.

 

IPB Image

Edited by mouz

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Hello...it's me again :bash: problem problem....

 

I soldered the opamp on the pcb and tried testing it using the method posted by uglyjoe HERE

 

All reading is around 2ohm except for U5 pin 7 where one probe at R4R returned 200ohm :cry:

 

Is this considered short or fried or just cold joint? :rclxub::helpsmilie:

 

 

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wat reading did u get when u measure using the usual way, from the pin to pad? reflowing the solder on those 2 points might help

 

Edited by mouz

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Thanks for the tip, pardon me but what do you set to to measure capacitance? ohm, VDC, etc?

 

Mouz, sorry brother, your DMM got no capacitance measurement.

 

 

 

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Mouz, sorry brother, your DMM got no capacitance measurement.

 

hmm.. looks like i need to in a better one soon. Got that for $10 cos i was thinking I won't get serious into this. So you got any recommendations? Fluke 73 series? Saw some 2nd ones on sale :). Sorry ar, i still very new into these things so need to ask noobie qns like this haha!

 

I've just solder the opamp so your usual way is the one at amb.org or by measuring the opamp pin to pad reading?

 

yup, opamp pin to pad.

Edited by mouz

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actually follow uglyjoe method all zero resistance except for pin 7. didn't adj the meter when i first checked the reading.

 

from opamp pin to pad all return zero. is this normal? shall i continue to finish the rest cause removing the opamp after putting in all the components going to be difficult.

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hmm.. looks like i need to in a better one soon. Got that for $10 cos i was thinking I won't get serious into this. So you got any recommendations?

 

I got a Sanwa CD800a from Sim Lim Tower abt two years ago. Forgot how much already sorry. Ask around on level 3 for pricing. The shop I got it from is 4 doors to the left when facing Kaichin (the one with components not recycled parts).

 

 

actually follow uglyjoe method all zero resistance except for pin 7. didn't adj the meter when i first checked the reading.

 

What uglyjoe method? Can post the link?

 

from opamp pin to pad all return zero. is this normal? shall i continue to finish the rest cause removing the opamp after putting in all the components going to be difficult.

 

That's normal and means each pin is soldered to pad. But doesn't guarantee that the opamp will be ok especially the AD8397. This opamp is very sensitive to shorts elsewhere. Make sure the pcb is clean before apply power which will happen when you solder the battery tabs. And be very careful afterwards to drain the caps immediately before touching the amp.

 

 

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koba also carries the sanwa MM. I bought the analog YX360 not too long ago. the uncle showed me both digital and analog but i bought the analog one...took me some time to get use to the different meter reading ... digital is much easier for lazy ppl like me

 

 

What uglyjoe method? Can post the link?

That's normal and means each pin is soldered to pad. But doesn't guarantee that the opamp will be ok especially the AD8397. This opamp is very sensitive to shorts elsewhere. Make sure the pcb is clean before apply power which will happen when you solder the battery tabs. And be very careful afterwards to drain the caps immediately before touching the amp.

 

 

Uglyjoe method link found in post 18 above. ;)

 

I just started the opamp soldering and now i dare not continue. so there is no way i can tell whether AD8397 is faulty or not.... :sweat: luckily i ordered another 8397 as spare...i knew it won't be that easy for me :wacko:

 

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koba also carries the sanwa MM. I bought the analog YX360 not too long ago. the uncle showed me both digital and analog but i bought the analog one...took me some time to get use to the different meter reading ... digital is much easier for lazy ppl like me

 

 

Uglyjoe method link found in post 18 above. ;)

 

I just started the opamp soldering and now i dare not continue. so there is no way i can tell whether AD8397 is faulty or not.... :sweat: luckily i ordered another 8397 as spare...i knew it won't be that easy for me :wacko:

 

Actually analog is faster. DMM always take time to settle down, quite irritating sometimes. Sorry about the uglyjoe link, old man lah, cannot remember lah. :blush:

 

Looks like you need to reflow the components connected to pin 7.

Edited by heady

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Ok...finally I finished my Mini3 on Tuesday nite with lots of detemination and discipline on how many components I solder each day to avoid complaints from my home minister.

:bash:

 

ok :b2t ... the AD8397 was actually working fine from the beginning. uglyjoe pointed pin 7 to the wrong resistor. Discovered it after checking the diagram. :doh:

 

Last nite, spend a few hours testing the amp following amb's method and duh...things went wrong again!!!!

 

First it passes all the test and i was full of expecation and relief...but when i plug in the earphone...how come it sounds like my first jaben cmoy but no matter where i touch it just won't sound sweet!!! :rclxub:

 

The led that i temporary "cucuk" in the hole also didn't light up and I am so afraid of shorting the amp i didn't try listening it with the wall charger on.

 

I thought it's another write off...until i decided to try it with the power adapter on... :cans: suddenly...i got the music back...it's all because of the low battery power !!!

 

The 9v I bought from SLT has less than 5v after using it on the jaben cmoy for less than 2 hours!!

 

Now can't wait to box it :holiday::thumbup:

Edited by adn6244

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