Axent SL-1600 powered sub

[gonetropo]

Hi all from NZ. I have a tricky one here. the subwoofer power on relay "chatters" on and off despite no signal input. output transistors are fine. no DC output to cause the protection circuit to engage.
anyone seen this fault before?

[budm]

Re: Axent SL-1600 Subwoofer fault.

Good clear pictures of what we are dealing with also help.

[gonetropo]

Axent SL-1600 powered sub

hi all from a wet and miserable Christchurch day in NZ, yesterday 24 C today 14 and raining.
anyways i have inherited the above sub-woofer, protection/power relay chatters on and off after a few seconds after power on. no dc on the output, output trans measure fine. all semi's before output stage measure ok too. any help appreciated. cheers all

[stj]

Re: Axent SL-1600 powered sub

resolder the relay and see if it still does it.

[gonetropo]

Re: Axent SL-1600 powered sub

nope. been there done that
thanks

[R_J]

Re: Axent SL-1600 powered sub

Usually if the relay chatters its supply voltage is low or has lots of ac ripple, check its voltage and see what it is and if its enough to keep the relay energized.

[gonetropo]

Re: Axent SL-1600 powered sub

R_J. supply voltage is perfect. no ripple on the rails. thanks

[stj]

Re: Axent SL-1600 powered sub

desolder the relay and power it from a battery or something - maybe it's bad.

[gonetropo]

Re: Axent SL-1600 powered sub

desolder the relay and power it from a battery or something - maybe it's bad.

done that too

[budm]

Re: Axent SL-1600 powered sub

Its time to show us some good clear pictures that show all the board to see how they are all connected together and the pictures of each board.


Originally Posted by stj View Post
desolder the relay and power it from a battery or something - maybe it's bad.
done that too

If applying DC directly to the (removed relay) relay coil and it still shattering then it has to be bad relay. BTW, when you apply the Voltage to the coil, what is the DCV of the coil Voltage?

[gonetropo]

Re: Axent SL-1600 powered sub

Its time to show us some good clear pictures that show all the board to see how they are all connected together and the pictures of each board.


Originally Posted by stj View Post
desolder the relay and power it from a battery or something - maybe it's bad.
done that too

If applying DC directly to the (removed relay) relay coil and it still shattering then it has to be bad relay. BTW, when you apply the Voltage to the coil, what is the DCV of the coil Voltage?

its a 12v dc dpdt relay, on my bench supply it will still change over at 9V

[budm]

Re: Axent SL-1600 powered sub

So if you apply 12V to the relay coil, the relay DOES NOT shatter, right? So it clicks to close the contacts and stay that way until the power is taken away, If that is the case then you need to look at the relay drive circuit.
Or it still shatters?
BTW, typical pull-in Voltage for the relay coil is about 75% of the rated coil Voltage.