Triac blowing fuses?

[Roy]

My 1986 triac is blowing both of the 3.15 amp fuses (f2 & f3) on the power section of the pnc main board when the board is powered up.
Any ideas what would be causing this?

This is the only section of the board I use as I have piggy backed off of this for Mach 3 & been running fine for several years!
I have recently just moved the triacs electrics into a stand alone cabinet, but all wiring is exactly as it was before when everything was working fine.

Cheers Roy

[alanhende]

Hi Roy,
Can you send me a picture of the area where the fuses are blowing. this will give me an idea of what version of pcb you have. It should be relatively easy to fix.

[Roy]

Hi Alan,
Many thanks for your prompt reply.
Here is a view of the complete set-up in the old drawer, and then in the new cabinet.(a few weeks ago before wiring complete)
The last one shows a close up of the problem area, (fuses removed)
Its fuse F2 & F3 which are both 3.15 Amp time delay ones.
Cheers, Roy

[Roy]

Still trying to figure this out, I remember reading somewhere that if there is a problem with the 12v it automatically shuts down the 5v?
I have been using the old 12v supply for the stereo unit to power the 5v (via a voltage regulator) for my breakout board. Could this be part of the issue? Would seem strange though as was working fine

[Roy]

So I've now disconnected my use of the 12v stereo supply. Fuse f2 is now holding out, but f3 is still blowing, although not straight away as before.
Still puzzled

[Roy]

Ok so having some success by not using the stepped down 12v (former stereo) supply and using a standalone supply for the breakout board power.
The fuses were holding out.
However after turning the drives off this morning & then switching them back on, this capacitor has blown. !!!
Whats going on? Is it possible this capacitor was on its way out and causing the fuses to blow?



Cheers, Roy

[Roy]

New capacitor fitted, now back to blowing fuse f3 every now and then??