Trident F6 fuse blowing

[Boots]

Anyone got any suggestions as to why my Trident is blowing fuse F6 on power up?
I have rebuilt the rectifier board with new bridges and resistors and diodes, and when I test it in the machine I only have J2 and J3 connected.
As soon as I turn the power on it blows fuse F6.


Cheers

[Mr Pinbologist]

make sure the bridges are installed the correct way, could also possibly be A shorted varistor VR1?

You could try removing all of the other fuses except F6 and see if it still blows, if it does blow F6 without the other fuses installed, it could be shorted wiring between the transformer and the PCB, or worse case scenario.. shorted windings the the transformer itsself.

If the F6 fuse does not blow with the others removed, you could try reinstalling each fuse, one at at time until you come to the one which creates the fault,

oh.. and have J3 removed as well while testing!

hope this helps!!

Cheers... Mitch

[Boots]

make sure the bridges are installed the correct way, could also possibly be A shorted varistor VR1?

You could try removing all of the other fuses except F6 and see if it still blows, if it does blow F6 without the other fuses installed, it could be shorted wiring between the transformer and the PCB, or worse case scenario.. shorted windings the the transformer itsself.

If the F6 fuse does not blow with the others removed, you could try reinstalling each fuse, one at at time until you come to the one which creates the fault,

oh.. and have J3 removed as well while testing!

hope this helps!!

Cheers... Mitch

Thanks Mitch
I have tried with the varistor removed and still no good, and with all the other fuses removed.
I have noticed a bit of melted wax around the transformer, I hope its not the transformer.
I put my meter on the 240V input to the transformer and it gets about 5 ohms, which is the same as my Meteor transformer, so I am assuming its ok.
I am really pulling my hair out on this, it looks so simple but yet its no good.
I am going to double check (again) the bridges and see if I can get anywhere there

[ddstoys]

Try using the fuse out of your meteor maybe you got a dud batch of fuses.    I got some cheapies off eBay that were just crap

[Boots]

Hmm
I bought the fuses from AZtronics here in Adelaide, usually they are ok
After blowing a couple I started using my 5 amp resettable instead of going through a fist full of 3amp slow blows.
Do you think the 5 amp resettable would be ok for testing??

[ddstoys]

2 amps is a fair difference but if it's only the rectifier board connect should be ok but wait for further instruction from the electrical whizz kids

[Mr Pinbologist]

so its still blowing F6 with all the other fuses removed??

If its measuring 5 ohms DC on the primary (same as your Meteor transformer) then the primary winding is most likely ok.
Sounds to me there could be shorted turns in one of the secondary windings, though i could be wrong... but if the F6 primary fuse is still blowing with no secondary fuses in, that does rule out any of the bridges or diodes.

You could probably try a slightly larger fuse, say 4 amp or maybe a 5amp fast blow should be safe enough. If the bigger fuse still blows with no secondary fuses in then transformer is very likely stuffed.

[Boots]

so its still blowing F6 with all the other fuses removed??

If its measuring 5 ohms DC on the primary (same as your Meteor transformer) then the primary winding is most likely ok.
Sounds to me there could be shorted turns in one of the secondary windings, though i could be wrong... but if the F6 primary fuse is still blowing with no secondary fuses in, that does rule out any of the bridges or diodes.

You could probably try a slightly larger fuse, say 4 amp or maybe a 5amp fast blow should be safe enough. If the bigger fuse still blows with no secondary fuses in then transformer is very likely stuffed.

Well I just thought what the hell, its not working now so I put a 10 amp fuse in and carefully gave it a go.
I could actually see the fuse start to warp as I started to plug the power cord in and it was definately going to blow.
So it looks like the transformer is rooted!
I guess my next question is, has anyone in Adelaide got a transformer for sale?

[FirePower]

So it looks like the transformer is rooted!

Hi Chris,

Hmmmm ... transformers are pretty simply devices not that prone to failure.  I'm not familiar with Sterms, but you sound despersate, so a few ideas;
 -  History of the machine - is it wired for the correct voltage?  If it's configured for 110V input then the output voltages will be approx twice what they should
 -  Remove all connections and just use the meter to measure transformer output voltage - with nothing connectied it should be a bit above the nominal voltage. What is it?
 - maybe post a fragment  of the schematic of the area of interest and you might draw a few comments and ideas
 - test rectifier board into other machine

Good luck.

[Boots]

It is wired for 240V, I think I might have to disconnect the transformer completely and remove the rectifier from the picture completely.
Then I can just connect to it with an inline fuse and give it a go.
Although with all the fuses removed except for the main input F6 fuse I think the transformer is effectively disconnected anyway????
It is a pain in the bum disconnecting all the cables from the transformer, but I guess I am going to have to do that anyway if its stuffed.

And yes I am desperate!

[Mr Pinbologist]

Although with all the fuses removed except for the main input F6 fuse I think the transformer is effectively disconnected anyway????

Yes thats correct, only other possibility i can think of, but i dont think its real likely, is that somehow there is a short in the wiring to the pcb from the transformer 

[Boots]

Nope, just checked the transformer completely disconnected from the board and no good, blows the fuse straight away.
I even tried wiring the transformer for 110V and run it through a separate 240V to 110V transformer and it does work but with a fair bit of snap crackle and pop.
After 1-2 minutes it starts to smoke.
Anyone got a spare transformer?

[chris288]

I got one from Bikecity warehouse in Melb about a year ago.

It was a genuine Stern and included the rectifier board. It was a bout $80 from memory.

Call em on 03/93579813

[Boots]

I got one from Bikecity warehouse in Melb about a year ago.

It was a genuine Stern and included the rectifier board. It was a bout $80 from memory.

Call em on 03/93579813

Thanks, good to know, but I will try and source one local first.

[FirePower]

Sounds like you've found the fault with the transformer and it sounds like it's a failure in the primary windings?  That's if I'm reading what your saying correctly (I don't have and so have not looked at the schematic, but am assuming F6 is the 240V inlet fuse) and if this is the case another test you could do to confirm is to measure separately the resistance of each of the two primary windings.  There should be a large difference between the two to account for this failure if the suggestion is that one of the windings has shorted?

If it's stuffed then who cares, but maybe this is interesting?