I've made a start :) 50w #102

[norburybrook]

Ok good, now put your meter (ohms) across the each of the 22M resistors on the PAB relay and flip the PAB switch.

do you mean across the pair of them or each individually?

marcus

[martin manning]

Each individually. You should see 22M or some high value that depends on the bass pot setting going to zero.

[norburybrook]

I seem to be getting 0.1R on both resistors regardless of switching.


mArcus

[martin manning]

That says the relay is not switching. Measure voltage across the relay coil (across the diode) with the switch in both positions.

[norburybrook]

It's -4.9 and 0


M

[norburybrook]

Ok.


I've rigged up my Voodoolabs power supply to give me 5v and have made a cable with bare ends to check the relay. I've put the cable ends directly on the underside board coil pins and nothing on either relay. Now the voodoo labs can only give out 100ma on this output, is it a current issue, do the relays need a lot of current, or have I got 2 bad relays?


Can't believe I'd get 2 bad relays.


MArcus

[martin manning]

You're sure that they are 5V relays?

[norburybrook]

yep, says so on the top of them, I had the same thought and wondered if someone at Mouser had packed the wrong ones but no.

I was reluctant to wind up the voltage to see if I could them to switch at some point.

Would I damage them by doing that?


Marcus

[martin manning]

They have some overvoltage tolerance but with 5V there that's not it. Are you sure the diodes are installed correctly, with the banded end connected to the +5V lead from the relay supply? The measurement across the coil says yes, but I'm running out of ideas.

[norburybrook]

yes, see picture.

mArcus

[rogb]

This is what I used
G5V-2-H1-DC5

Just checked the data sheets - they seem virtually identical.

http://uk.mouser.com/ProductDetail/Omro ... hwGQ%3D%3D

[martin manning]

The diagram on the top of the relay says bottom view, which suggests your polarity is reversed.

[norburybrook]

you know what martin, I had the same thought, then wondered why on earth would you put a diagram on top of something showing the bottom as if you were looking at the bottom and not through it, as it were.

I'll swap the diodes round.

Marcus

[norburybrook]

swapped the diode round on the PAb no difference.

As I said I put a separate 5v feed directly on to the coils and the relay didn't switch regardless of which way round I did it.

surely that means both relays are faulty, I just can't believe a quality product like this would be.

marcus

[martin manning]

If the relay is polarized that might mean it has an internal diode. If your outboard diode was opposite in polarity it would short out the coil. You need to reverse your diode and reverse the + and - connections to the power supply to test it.