AMB Laboratories DIY Audio

[chipbu]

I finished assembling the mini3 sometimes ago and now I try to check that my assembled mini3 is working all right. Saniti check was ok, but quiesent current check showed no result. My reading on DMM shows 0mA. I dont really know what went wrong here. All my soldering point seemed fine, no solder bridge. But there is one thing about the battery: it is only 6.48V when I measured it. I know it has to be 9V for the amp to work.

my question is: Do I still have quiesent current at 6.48V battery ? If so then could you guys suggest what went wrong?

Appreciate any help.

[amb]

Your battery is near dead but the quiescent current should still be above zero. Did you remember to turn the amp on to do this measurement? Did you set the meter to DC mA (and plugged the probe leads into the appropriate jacks on the DMM for current measurement)? If so, check the fuse in your DMM. Maybe it's blown.

[chipbu]

I did measure it again with the amp turned on but nothing was there - no current. I just bought my DMM 3 days ago so I dont think it's the problem.So one thing remains: the battery. I'll try to recharge it and see what happen next.

Can I charge the battery by those dosmetic chargers?

[amb]

I did measure it again with the amp turned on but nothing was there - no current. I just bought my DMM 3 days ago so I dont think it's the problem.So one thing remains: the battery. I'll try to recharge it and see what happen next.

Check the fuse anyway. It will blow if you tried to measure voltage while the meter is set up to measure current. This is a very common usage mistake... been there done that!

One clue, does the amp's power LED come on when your battery is connected normally? Does it not come on when you're checking quiescent current? If both of these are true then chances are your meter fuse is the culprit.

Can I charge the battery by those dosmetic chargers?

What domestic charger, specifically? And what battery?

[chipbu]

Thanks for the tip amb, it is a blown fuse. I've got to change it right away. And what should I use to charge the Accupower NiMH 8.4V 300mAh?

[amb]

And what should I use to charge the Accupower NiMH 8.4V 300mAh?

If your Mini³ passes the battery charging current check, you could use it to charge the battery (assuming that you have an appropriate AC-DC adapter).
Otherwise, a special outboard charger designed to charge NiMH 9V batteries could be used.

[chipbu]

There is a prolem with the charging current test: C2 blew. I did check for the output voltage of the wallwart - 21.6V, so it's in the allowed range. The next thing I knew was that right after I plug the adpater DC output into Mini3 DC input, C2 blew. Do you have any suggestion for what went wrong?

[hagak]

C2 is a polarized cap so my guess is you had it installed backwards.

[chipbu]

true, I didn't konw that tantalum capacitors are polarised. Luckily, I have a spare one, phew

[LDme]

i also have Quiesent Current check - 0mA, but all parts solder property & this problem i have on both my mini3
2 mini3 all done, led checked ok, but

connect the meter across the battery's negative terminal and the board's negative battery contact as shown

- 0ma
can anyone help me?