Any electronics wizard in here?

[the snooper]

They may be Triacs of course

if they were they would be very easy to substitute

 

[WorkshopChris]

The most info I can find is when I look for rectifier and it is in the power circuit as when you switch on the power it just powers it up ready and just now if I try and power it up without even thinking about the operation of the door it wipes out the power to the garage.

Does it trip out as soon as its powered up, have you tested continuity to earth?

 

[Exuptoy]

It doesn't knock out my RCD but it does knock out the circuit breaker so I'd assume the problem is an imbalance/short circuit in L-N feed but only after switching on board mounted power switch.

 

[Exuptoy]

Here you go then.....good luck.

 

[voipio]

The fact it's tripping the circuit breaker suggests something else is shorted or is presenting a very heavy load.

 

[Exuptoy]

Looks like the centre pin on all 3 x "diodes" seems to be common to the HorsePower resistor.

 

[Exuptoy]

The fact it's tripping the circuit breaker suggests something else is shorted or is presenting a very heavy load.

Which is why I am querying the power circuit as at that point that is the only part of the system that is operational and if the "diode" is part of the rectification of the power circuit then that could explain it.

 

[WorkshopChris]

Ok trying to flip from front to back . They would appear to be operating as diodes as unless that board has a hidden layer they are only connected on 2 legs.

 

[voipio]

Looking at the right hand legs of the rightmost three TO220 devices, those legs are soldered to pads that don't appear to have any other connections. Is that correct? If so, they would be diodes, not SCRs or triacs.

 

[Exuptoy]

Right, the power cable (white) is shared with the centre leg of SCR1 which is also linked (by black cable) with the left leg of Diode 14 (I thought it was diode 11,12 & 13 but it's D13, 14, 15) and the Blue power cable (neutral) is common to the centre leg of SCR2 and linked to the left leg of Diode 13. Left legs of SCR1, SCR2 and D15 are all commoned up.

 

[WorkshopChris]

Looking at the right hand legs of the rightmost three TO220 devices, those legs are soldered to pads that don't appear to have any other connections. Is that correct? If so, they would be diodes, not SCRs or triacs.

THat how i see it at the moment, black cable links across to devices at the other end.

 

[Exuptoy]

And your correct in the assumption that the right hand three diodes are only using 2 legs. I can see through the board with a torch and there is no second layer.

 

[Exuptoy]

THat how i see it at the moment, black cable links across to devices at the other end.

One from the live and one from the neutral via the SCR centre pins.

 

[WorkshopChris]

I need less drugs in me and two monitors for this, but not going down to office while its wet and slippery out. As soon as i get a print out will try to trace it back.

 

[Exuptoy]

I wouldn't be able to remove one of the diodes to try and substitute then as I'd just be breaking the other half of the power circuit.

 

[Exuptoy]

I need less drugs in me and two monitors for this, but not going down to office while its wet and slippery out. As soon as i get a print out will try to trace it back.

Haha. Thanks for the assistance all.

 

[WorkshopChris]

One from the live and one from the neutral via the SCR centre pins.

That would make sense.

 

[Exuptoy]

So could this just be down to something as simple as a bit of condensation wiping out one leg due to tracking across to the other leg of the power diodes? If so then I just need to find a compatible power diode.

 

[WorkshopChris]

Maybe, will see if i can see anything suspect in the morning but might be worth a try.
Power it up via a lamp limiter.

 

[Exuptoy]

I'm sure Littlefuse sell 15a, 20a and 25a rectifier diodes. like this.

http://www.littelfuse.com/products/switching-thyristors/rectifier-diode/dxx15l-dxx20l-dxx25l.aspx

and in my understanding the Multidrive is rated at 8a at full load with a 3/4 horse motor and 16a with a 1 1/2 horse motor at 230v so a 15a switching thyristor / rectifier diode would do it? The motor is only 1/2 hp