You man those little surface mount caps? I have no SMT tooling to pull them

What voltages does U16 (the L4960) supply?

Is the +5 taken from the +12?

There's a controller card on eBay for $500,, but I have no dongle, am I wasting my time?

Is there any history of this type problem? When I worked as a repair tech in a mfr environment, I found a mfr problem where the silkscreen lifted up a little when the PC board was exposed to light. This created a short on the top layer of a multi layer PCB. I think they were 30 meg boards, double si...

As a side note looks like U16, the L4960 has been replaced at some point.
So that IC is suspect, but if it was replaced, then something else might be a cause,,,

Already pulled the two KBU8D's and they test fine with my DMM. I have two replacements and just to verify, I just now compared the old with the new.

I checked the tracks from the edge connector to the rectifiers, but not sure where the other sides go.

Denstep Controller with a Baldor Optmized controller board F391 Issue 2 We have 24 VAC going into the board and fuse F1 is good., but no +12 -12 +5 volts. I have no schematic drawing and the link here to st.com doesn't work Since all voltages are gone, I would suspect a component that uses all three...

Steve wrote:
See the attached link for information on the circuit.


https://www.st.com/stonline/books/pdf/docs/1734.pdf

Bad Link any hope in finding a good one?

Removed the bridge rectifiers, but they test good,,,

What's the most likely issue pulling the +12 and +5 volts down?

What could pull both voltages down?

Any possibility of getting a schematic for the Baldor Optimized Control F391 issue 2 PC Board?

Removed all connectors but the 24VAC in to the Baldor board.
No LED light.
I then removed the piggyback board (with the LED) and still no volts,,, suspecting the diodes again.

On a side not, it's 28 VAC RMS according to my meter, but that's probably cause it's unloaded.

After some serious investigating (and reading the user's manual) I've determined that the key switch is a momentary switch. So I'm thinking, maybe, cross my fingers, maybe, tying the two orange key switch wires together, might have preveneted Voltages. I put the entire thing back together (had the B...

Back with another stupid question,,, the keyswitch, is it momentary, or On/Off?
I don't have a key and hard wired the two orange wires together.

Looks more like a Denstep, with 24VAC supplied for both drives and logic. And from looking at the Denstep schematic, looks like the E stop cuts power to the Xformer I have 24VAC, so it's not a bad E stop button. Since the logic doesn't like 24VAC, (as per an earlier post) is there a "fix" I can do t...

Got the Baldor board out, easier than I thought From what I'm piecing together, the Spindle drive is a small pc board that sits above the transformer. Looks like there is a jumper (blue wire) between TB1-6 and TB1-2 (Stop and Grnd) Looks like I have some type of mutation between smartstep and next s...

TY, I couldn't tell by just looking at them, and didn't want to go Yanking on a UK board. (Pun intended)

I am SMT solder certified by Data General,,, used to work on 4 meg double sided SMT PCBs,,, about 18"x6" in size I would very much like to get this machine up and running, but buying a new Board is out of the question, as is being able to afford a tech to fix it. Do the Orange connectors remove from...

Would like to verify, but I think the KBU8D rectifiers are pretty much toasted, as I dont have +5 +12 -12 volts. So what kind of challenge is it to replace the rectifiers? How do the Orange conenctors come off the board? Do I need to do anything with the drive transistors on the big heatsink? Or wil...

From what I've seen, it's looking like the two big rectifiers on the Baldor board are fried.

I measure 28VAC on the power in connector both between pins 1 & 2 and between pins 4 & 5. (The link showed that 4 & 5 should be DC voltage, I hvae 0 volts DC between 4 & 5. ???? Which, if I would have taken off the cable trough cover, I would have seen that pins 1 and 2 are jumpered to pins 4 and 5,...

Not sure what I have is called, but here's a picture.
Did not get any flicker at all from the 7 segment LED when powering up or powering down.