powered sub wont come out of standby

[budm]

Re: powered sub wont come out of standby

Since now you have relay removed, now check to see if you have DCV on the speaker leads against circuit GND.
BTW, Q17 is the relay driver transistor, D15 is the snubber diode for the relay coil.
Also check the resistance between the middle pad where the middle relay's pin was against GND to see if it shows <1 Ohms for me.

[moss99]

Re: powered sub wont come out of standby

yes i have dc voltage on both speaker leads , it started at 5 vdc and is slowly climbing it got to 7.5 and i powered off , led is green .

[moss99]

Re: powered sub wont come out of standby



This pad on the top side of the board goes to ground .

[petehall347]

Re: powered sub wont come out of standby

what voltage is across where relay coil goes ?

[moss99]

Re: powered sub wont come out of standby

what voltage is across where relay coil goes ?

These readings are with the relay removed , its an earlier photo .

On pin 1 (with the ground probe on center pin of J6) .3 v dc , on pin 2: -12 vdc .
with red probe on pin 1 and black probe on pin 2 i get 4 vdc.

[petehall347]

Re: powered sub wont come out of standby

looks like relay voltage is way too low . maybe the driver transistor is wonky or its not being turned on enough .
i could do with seeing the schematic really to see how the circuit works ..
it doesnt appear to be the same as i am used to . looks like ground is hard wired to relay coil . i am used to seeing the driver transistor between ground and relay coil .

[moss99]

Re: powered sub wont come out of standby

Unfortunately apex have said the could not get the driver to this board , typical they have schematics for the good boards ,,

[budm]

Re: powered sub wont come out of standby

These readings are with the relay removed , its an earlier photo .

On pin 1 (with the ground probe on center pin of J6) .3 v dc , on pin 2: -12 vdc .
with red probe on pin 1 and black probe on pin 2 i get 4 vdc.

That first reading it means the relay coil has 12.3VDC (the V diff between the two pins, +0.3V and -12V).

Second reading is 4VDC on the coil, that has to be measurement error. Are you sure?
As you can see pin 1 is connected to the Cathode of the snubber diode so pin 1 should be more positive that pin 2.
If pin 1 is GND then the relay is using high side driving circuit with Negative power supply because you are reporting -12V.

[moss99]

Re: powered sub wont come out of standby

Hi guys , im about ready to give up on this , i thought i had found something , i noticed when i moved this coil the led would flicker green/ red , i took the capacitor out next to it ,(circled in the drawing ) as couldnt get a reading from it from my esr meter .
Replaced it and after a few seconds the relay clicked and green led , tried it a couple times and seemed ok . but now back to red led again .