New Owner Mint3.28 hang up

[mespe]

Just got a micromill Scantech 2000

OS Win98
I've played with com ports I/O $3F8 IRQ 4 and $2F8 IRQ 3 in fanucsmd.go
Removed modem
Set com1 = $3F8 & IRQ 4

I get hung up at Mint3.28 (If it makes it that far,,, makes it that far in a windows box, but I don't get to that message when I boot to a Dos prompt and start the program from the C:\Denford directory)

I made a Baldor to PC Cable as directed in a posting here viewtopic.php?t=231


Took the cover off the back of the mill, Nothing on the 7 segment LED when power applied

EPROM V1.6h/S JD5


I tried changing baud rate, parity, flow control,, nothing gets me past mint3.28

I read something about a dongle. I never got one, do I need it to proceed?

Few other observations,,, I hear relay click when front door is open.
Spindle control works unless front door is open.
Spindle works regardless of "E" stop position
did not hear any relay clicking when "E" stop pressed (or turned to the right and "popped" out.

1 fuse, checked out OK

Checked voltaqes at TB10 not good, do not have 5 volts +12 or -12. Think they all read around 1 V,,,

HELP I don't want to buy a new power supply for this thing,,,

[Martin]

The red seven segment LED on the Denstep control needs to be lit in order to connect. Check the control voltage. If you have a Smartstep Control then check fuse F1 on the card.
I have also seen the Smartstep fail on overvoltage. The easy well to tell is to check if the LED lights when you turn the power off. I think it trips around 29Volts AC. In this case you can change the supply to the 24Volt DC supply, wires 60 & 61.

[mespe]

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.

[Martin]

It's a NextStep.
Check out this link.

viewtopic.php?f=54&t=2126

[mespe]

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, thus the same voltage.

IMG_6412.JPG (65 KiB) Viewed 17815 times

[mespe]

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

IMG_6387a.jpg (196.09 KiB) Viewed 17828 times

[mespe]

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 will I have access to the underside of the PCB to remove the Diodes?

What could have toasted them? A spindle crash? This machine was used in a high school.

[mespe]

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 the PCB, or are they soldered?

[Martin]

The orange connectors are just plugs with the socket soldered to the board.

[mespe]

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

[mespe]

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 step.

Could the blue jumper between stop and ground be causing my problem?

i.e. was in school, previous instructor put a jumper on it so kids don't mess around,,, I dunno, can't seem to find any one schematic that fits what I got.

[mespe]

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 to give it DC without messing with the PCB or replacing the transformer?
Or should it work fine the way it is,,, well wait a minute, it's not working at the moment,,,

Appreciate the help so far,,,
Hope not to be a PITA

[mespe]

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.

[mespe]

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 Baldor board removed to change the Rectifiers, which look suspect, but not 100% positive) smae problem, no 7 segment display.

Back to bad diodes,,, but could me tying the two orange wires together have fried the diodes? I think unlikely.

Now that I know which diagrams to look at, maybe I can get this thing working again.

AND

PLEASE ADVISE ABOUT 24 VAC GOING TO LOGIC FIX

[Martin]

24 volts AC or DC should be fine for the logic. You may have something pulling the board down as we say, so you could try to power up without any of the other plugs connected. If it does not power up any LED's then the fault may be terminal.

[mespe]

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.

[Martin]

It trips out on overvoltage at 29.5volts ac but the easy way to check is on power off if the red seven segment led centre line turns on for fraction of a second.

[mespe]

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?

[black5f]

Hi. All I can say is what took mine down. The little brown caps are mostly decoupling caps connected from the V rails to ground. They have a limited life and go short. I replaced mine with ones stolen from a 10 base ethernet card and has worked fine for the last 5 years (my board is similar and dates back to 1991). Hope that helps and hope it's not a red herring. I soldered mine but having legs they can be snipped and checked.

Tom

[mespe]

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