AMB Laboratories DIY Audio

[amb]

i also have Quiesent Current check - 0mA

Blown fuse in your meter?

[LDme]

oh crap, another problem
one of my mini3 is broken
i'v accidentally touched battery to wrong side on battery contacts - someone can tell me - what did i blow?

[amb]

oh crap, another problem
one of my mini3 is broken
i'v accidentally touched battery to wrong side on battery contacts - someone can tell me - what did i blow?

Do you mean you had the battery connected in reverse-polarity? If so, usually the D4 zener diode would fry.

[LDme]

Do you mean you had the battery connected in reverse-polarity? If so, usually the D4 zener diode would fry.

how can i check it? i have 2 mini3 assembl pcb - but i forget where it was happend
(& what it for (D4)?) in couple words.

[amb]

how can i check it? i have 2 mini3 assembl pcb - but i forget where it was happend

Measure the resistance of D4 (while battery is removed) in both directions. You should not read a short circuit, or very low resistance readings.

(& what it for (D4)?) in couple words.

??

[LDme]

how can i check it? i have 2 mini3 assembl pcb - but i forget where it was happend

Measure the resistance of D4 (while battery is removed) in both directions. You should not read a short circuit, or very low resistance readings.

(& what it for (D4)?) in couple words.

??

first D4 have 84 Kohm & 100 Kohm in another direction.
second have infinity in both directions.
so, first is bad?

[amb]

Are you sure those readings are 84K and 100K ohms rather than 84 ohms and 100 ohms? Typically when a zener dies from being driven backwards with too much current it goes low resistance.

[LDme]

Are you sure those readings are 84K and 100K ohms rather than 84 ohms and 100 ohms? Typically when a zener dies from being driven backwards with too much current it goes low resistance.

i have check it again, 80K and 100K
so - its broken? or not?

PS: both plays perfect - but im still afraid to charge it

[amb]

Does your DMM have a diode check mode? If so, remove the battery and use it to test D4. Put the red probe on anode and black probe on cathode (cathode is the side with the marking band) and you should read about 0.75V. Reverse the probes and you should read infinity.

[LDme]

D4 who have 84 Kohm & 100 Kohm in another direction have infinity in diode mode.
D4 who have infinity in both directions have 822 somethig in diode mode