Reposting my post here in the hope of some help?
viewtopic.php?f=47&t=5157&p=20416#p20416
Cheers Roy

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

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...

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

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 s...

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. Cheer...

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...

Ignore this it's not the transformer

Does anyone have the spec of the toroidal logic transformer in the triac PNC?
I think mine has had its day
Cheers Roy

Hi I am just drawing up a new bench for the Triac, as it will be moving home shortly. I am going to remove it from its base/electronics cabinet & fit directly to a new bespoke bench with coolant tray (Something I intended to do years ago when I did the Mach 3 conversion). I am away from the machine ...

Nice one Roy, How many Rudge 250s are there out there? What is the material specification? There probably about 300 + 250cc Rudges still about. Material is EN36B (3 1/4% Nickel chrome, 65 ton) These will now be hardened .040" deep to 65 HRC, then the side bearing faces surface ground & the bores ho...

Couple of pix to show how they work!

After my Triac has been laid up for about 2 years due to doing up a house, building a garage & many other projects. I finally got round to using it again this week, so thought I would post up a couple of pix of what I've been making. These are overhead rockers for a 1930's fully radial 250cc Rudge m...

Well we are cooking on gas again tonight. Made up the new interface board, fitted it and she was away once more.
Strange thing is I can not find anything amiss with the old board!!
Thanks for your input anyhow.

Cheers, Roy

Thanks Angeltech, I will knock up the new interface board tomorrow & give that a try. If I get no joy, I will run a wire as you suggest. I may have the experimental parrallel cable knocking about somewhere which I originally wired into the interface when I was first experimenting with the conversion...

Its a CNC4PC c11 breakout board into a homemade digiplan interface using 3K3 resistors & BC547 transistors (as per the digiplan manual). Its this interface board which is the one I am going to re-make tomorrow. I remember a couple of years back I had a transistor go down on it causing some issues. I...

been at it with a multimeter today. All wiring from the drives to the steppers seems to be good. I've been playing around with the outputs on the interface board (between breakout board & drive board). using the Z output I can replicate the problem on the X axis but still get the problem if I use th...

Iv'e given the stepper motor a good 'warm' 2 hours with the hair dryer, so I think thats eliminated any possible condensation. Still no Joy!
I will try and check the wiring from the stepper drives to the motors tommorow if possible. Only trouble is access being a pain!!!

Thanks, I'll have a look at that one then. Although I assume this will be ok as I swapped the X axis output (which I know is working) from my interface board to the Z to eliminate the breakout board & the interface board. hence I have a suspicition it is beyond this.

Cheers, Roy

Thanks. No Havent actually tried that one. Whereabouts should I be doing this. On the drive card?
Sorry but I am trying to get my head around it all again as its a couple of years since I played with the Triac electrics.
Cheers, Roy