I have a BP Series 1 CNC with a Limit Override light that will not go out when I push the button. I can manually click the CR1 relay and the light will dim and let me jog the machine. I can then push the limit override again and I hear a relay in the head click. I can jog it in G-code but it will not do anything when it gets to a feed. I have a feeling that there is a combination of relays that may not be working. Any ideas? The ACC board has a spot on it that is a little brown where it may have gotten hot. The z-axis also stalls when jogging. :drowning:

The BPT will run in rapid or jog with the spindle off. To do a feed rate it needs to see the spindle on. This is a safety feature to prevent bashing end mills into the side of a part. There are small switches on the side of the spindle motor contactors to tell the control that the spindle is on. There is another switch or each contactor that locks out the other direction contactor preventing both from turning on at the ame time.

Put the machine in jog, setup, z axis and step. press the minus button repeatedly. Each time you do watch the small shaft and dial benath the Z axis motor. made sure that it does not step in the same direction for three steps and then reverse direction for one. This would indicate a shorted final drive transistor (2N6547). There are 3 groups of these on black aliminum heat sinks above the ACC board.
It is also possible that you voltage in is wrong, you have a bad bridge rectifier, your current is set wrong, you have a chip or washer between two diodes on the small board beneath the ACC card, a chip or washer in the motor terminal strip beneath the ACC card, or the wrong transistors, or a high resistance in the Z axis DC fuse (screw in type, tan in color), or your quill needs to be claened with kerosene and use Mobil Vactra number 2 for way oil. I also once had a bad opto coupler on the ZDI to the SMD.
That gives you a bit to check.

George W.
Th

Thanks for your input. I have tried to run g-code with the spindle on but the same results. The machine is wired 230V 3 phase but I have 208 3 phase in my location. I did try jogging the z-axis repeatedly and it does not back up. I did check the bridge rectifiers as described in the manual. I checked the voltage on the x,y,z axis at the fuseholders per the manual and found 37V but it drops as I hold it longer. I checked the output voltage of the 56V power supply and it has about 54V. When I hit the limit switch relay CR1 the voltage drops to about 33V. Also, the manual said to check the current of the x,y,z at the fuseholders. I get no current there. I also checked inside the machine for chips or other stary matter. I also changed all the fuses. Thanks.

The BPT had a special transformer for a 208 VAC machine. If you have a SMS card you will see current and voltage drop slowly. It was an added board to help prevent final drive transistor blowing.
The drive DC fuses (12, 13, 14) should have about 9 to 9.5 volts with the drives on and a static (motors not turning) current of 8.0 to 8.2 amps. When the motors are turning in rapid, the voltage will come up to about 58VDC and the current will drop to about 2 amps. As the motors age, this current will go up and the motor torque will diminish. The magnets are losing their force.
The CR1 relay does not sound like it is puling in. Is the emergency stop button mashed in? Is the machine in extreme limit state? If you mash the limit over ride does the light go out? Have you tried holding the limit over ride button in and jogging the axis? Is the 24 VDC power supply ok?

George W.

I think I remember having similar symptoms when I hit an X limit switch, and the switch stuck. Maybe one of the limit switch plungers is stuck bottomed out with the switch made...

Simple things...

/Craig

I checked all the limit switches and they are good. Emergency stop not activated. All axis are not in limit state. I push the limit override and the light stays on. I tried holding the override button down and that doesn't help. I have to take the plastic cover off of CR1 and push the contacts over for it to engage and then the limit light goes dim and then I can jog the machine. According to the manual when pin 4 on the relay is at ground then the relay is off. Pin 4 is at ground and when I pull the wire off of pin 4 then the relay kicks. 24V supply checks out good. Will I be able to get this BPT usable with 208V on that 230V transformer or will I have to find one? The voltage at the fuse on the z-axis is about 17V when I try to jog it. Also the z has gone from stalling to just giving a whirrrr sound. I also cleaned the quill.

Pin 10, wire 135 at CR1 goes to the emergency stop switch. From there it goes to wire 39 which is ground for the 24 volts. 24 volts comes in at pin 2, wire 125 supplies 24 volts but there is a voltage dropping resistor R26 between it and wire 40, the actual 24 volt supply. The reason for this is they wanted the relay to barely hold in so it would react faster to a press of the emergency stop button. Try grounding wire 135 to see if CR1 pulls in. If it does, you may have a bad wire to the ESTOP switch or a bad ground or a loose or bad wire.

george W.

Make sure someone has not replaced CR1 with a 24V relay it should be 12v due to the dropping resistor.

Darek

Actually, CR1 IS a 24 volt device.

George W.

The ones I have seen were 12v and the dropping resistor allowed you to ground the positive side of the relay without shorting the 24v power supply.

Darek

You are correct. The 24 volts branch off through D16 just after that resistor to the limit of travel switches then to the limit override switch (normally closed), and then to ground. When you press the limit override switch, that circuit opens allowing CR1 to pull in since the voltage now is applied to it. I will have to find a machine or parts list and see if CR1 voltage is specified. I owned a BOSS 9 and it had the same circuit and CR1 was a 24 volt device. My service manager Norb Lion (BPT Bristol PA sales service center), explained it to me that this was designed in such a way to barely hold CR1 in and react quickly.

George W.

Sorry R26 and D14 not D16.

GTW

What I've been seeing may be what people were doing for a quick fix to this problem.
Problem being either the resistor resistance increasing, 24V power supply voltage decreasing or relay pull in voltage increasing over time (Possibly a combination of all.).

Darek

I checked and it is a 12V relay. Grounding the 135 makes the limit override work so now I will work on finding the cause. Any ideas what I should check to see why the z-axis is just whirrring and low voltage? Thanks for your help. I have been working on this things for weeks with manual in hand and your help brought me right to the problem. I will say that I have a much better understanding how these things work. :))

I just remembered that I had a Series 2 BOSS 6 manual scanned into my laptop. Section 13.2.1 has CR1 as a 12 V device part number 1501091. Well, I'll be dammed!
Next I have to find a BOSS 9 manual to save face.

George

From what you are describing the E-stop switch contact is bad or the ground wire going to it, wire #39, is unconnected.

Darek

That's what I thought. See reply 2-17-05, 9:22 PM.

GTW

I checked the current and on 2 axis there is ~8.2ADC. The other is 12.5ADC and will not adjust on the ACC board. I turned the ACC board over per the manual and it moved to another axis. Sounds like a bad ACC board? Is there any use trying to repair these or just replace? Now all three axis just give the whirrr sound when jogging. Could the ACC board cause all this or do you suspect other problems? Ever feel like a dog chasing it's tail? It has been an enjoyable learning experience anyway :)

If the non regulating current circuit switches axis, then it is very probable that the ACC is bad. Look on Ebay for a replacement.
Look at the large transformer in the back, top. The 1 st and 4th wires should be wires 11 and 12. This is the X axis AC power source. It then goes to fuse 15, then to the bridge rectifier. Most times the problem is too much voltage and a resultant blowing of those final drive transistors. You may not have enough. What does your meter indicate for X Y and Z at this transformer. You will notice that this transformer has higher taps. You may have to go to the next tap. Do not exceed 63VAC or you will blow a lot of transistors.
As long as we are at it lets check the logic power supplies, my way. Look for a short terminal strip toward the top of the logic poer supply. You are looking for 3 thin blue wires and 3 lavender (?) wires. Wires 76 and 79 are the 5VDC wires right from the board. Adjust the top pot on the FPS card for 5 VDC. Wires 76 and 67 are the 12VDC. that I believe is the bottom pot. Wires 76 and 59 give you -12VDC. That is adjusted by the middle pot.

GTW

11&12 56vac 13&14 55.6vac 15&16 55.6vac
76&79 4.9vdc
76&67 12.0vdc
76&58 -11.9vdc

I was looking at the ACC board and found that Q3 2N2905A has a broken wire where it goes into the transistor... :violin:

Note to Kewl CAt: Fix wire!
Those drive voltages are low but within the acceptable range.
I prefer 5 volts at 5 but control is working.
24 volts is there and 54 volts are there.
Yet the two good axis are stalling (whining and not moving).
Give me a list of the part numbers on the boards. I wonder if someone mixed up BOSS 5 and 6 boards.

George

The machine has Assem 1930788 Ser# 3282
XDI A026974
RCK 1926865
ERS 1927990
LSI-11 1927322
ACC A018568
SMD 027015 - x, y, z
I have it connected to my port on my pc and it comes up as Boss 5

And I ran a new wire. :)

All your boards match. I was concerned that the ERS might not match the rest. IE the BOSS 6 had a ZDI, NTP, ZCK, and an ERS. Thus I was curious what version of ERS you had. The ACC and SMD are the same.
Time to step back and see how bad this is since all is good. The whine means motors are trying to move, means that there is a high probability that control is good.
In setup and step, trying each axis, using at least 4 pushes of the +/- button, it will step 4 thou. ??
Go to the next increment. .01 per push. Does each axis do this?
.1 per push?
I am trying to see if your axis are all gummed up. I had a bet at a shop with the same problem and asked them to clean them all with Kero and fill with Mobil Vactra number 2. They were using some other oil that was too heavy. They were skeptikel (spelling) but did it anyway, and the machine went to running. Next time into Chrysler Huntsville, I took along a container of salt for the gentleman to eat his hat.

George

I don't want to eat a hat... I already cleaned the quill and I will do some more cleaning to make sure. The more I mess with this machine the weaker the whine gets with all three axis. They all just barely try to move and do not back up on the fourth jog.
Is there a good place to get those transistors online. Sounds like I need some backup transistors based on other threads I have read. I live in a small town and a good electronics store is about 35miles away :) Oh and the x axis keeps blowing the fuse when I try to jog it several times.

The readout says that the axis is moving but it does not move. I put my hand on the pulley for the z-axis and it twitches but does not move at all.

Moving these motors is a matter of energy. Volts X amps equals watts. I fnow the 230 V transformer uses taps 5 and 6. What do yo have in volts AC between taps 5 and 7? If it is 63 volts or less then I would move the wires from taps 6 to taps 7.
Did you retest the transistors you think are bad? Did you check the diodes?
Stupid question by me, does the limit override light go out? I do not believe the control would count in a limit state.

George

OK, I went a little backwards. I did originally check the transistors and they were fine. Now each axis has one bad transistor. Guess I will need those backups after all. Do you know the part#'s on the diodes in case I need some of them also. Any good online sources? I will also check the tap voltages here after work.

-rob

I have to find what I was issued when I worked for Bridgeport as far as the diodes go. I thought they were 1N4003 but the parts list in the book lists quite a few different diodes but not anything specific for the D42 through D53 designation of these per the schematic.
If I need old parts, I usally go to a place called DIGIKEY.

George

I have to find what I was issued when I worked for Bridgeport as far as the diodes go. I thought they were 1N4003 but the parts list in the book lists quite a few different diodes but not anything specific for the D42 through D53 designation of these per the schematic.
If I need old parts, I usally go to a place called DIGIKEY.

George

My series 2 has 1N457's on the back of each transistor... I couldn't locate the number in the manual, so I spent some time with a magnifier and managed to read the number on one... Not the best method, but better than nothing. Of course someone might have installed the wrong diode on every transistor sometime in the machine's past... Verification with the manual would be really nice...

/Craig.

Good news. I got some new transistors installed and the x & y axis will jog again. Z still whines. The problem I have now is that when I turn the spindle on it turns about a quarter turn and quits. I hit the green button and start again but it only goes about another quarter turn. It does the same in forward and reverse. I checked all the fuses and am not sure where to point next.
-rob

Make sure you have not lost a phase. The spindle may be "single phasing". Since the drive transformer is a three phase device, it may be that the Z is suffering from a lack of voltage and is stalling. Check power phase to phase and each phase to ground.

George

The contactor is getting voltage on all legs. Is there any fuses or resets for the spindle? I hit the reset on the overload.
-rob

Check your way lube level.

Darek

Way lube is about 3/4 full. I took the cover off the contactor and pushed it manually and the spindle starts and runs.
-rob

With power off check the continuity off the way lube level switch, wire #2 to wire #138.

Darek

Way lube switch checks out OK.

Well from there wire #138 goes through the overload NC contact and becomes wire #223 providing ground to both the foward and reverse relay coils. The power side starts as wire #3 goes through a NC contact of CR3 and becomes wire #213 that goes through a NO contact of CR5 and becomes wire #128 that goes through the E-Stop NC contact and becomes wire #217 that goes through the SPINDLE ON switch and becomes wire #218 that feeds both the foward and reverse switch to become wire #219 for forward and #221 for reverse. Wire #219 has to go through a NC contact on the reverse contactor to become wire #220 that supplies the forward contactor coil and wire #221 has to go through a NC contact on the forward contactor to become wire #222 that supplies the reverse contactor coil.

CR3 is the relay for program spindle stop.
CR5 is the relay for spindle brake.

Darek

Wire #138 & #223 check out having ground.
I chased the positive up to the Spindle On and #218 has about 109V. When I try to turn on the spindle then 219 & 221 get voltage momentarily. I have to hit the Limit Overide and the Spindle Enable again for it to do it again. How much voltage does the contactor coils take to engage them? I would assume the same 109V?
-rob

A couple of silly questions. Does the air brake turn off? If you turn the air off, and push up on the brake to release it, can you then turn the spindle by hand? I am trying to figure out if there is a broken belt or mechanical problem.
If you had float level isues, it would not even try to turn the spindle on. The fact that you are going into a limit state, means an overload is tripping or a limit switch is going open, or that string is dropping out dues to a voltage drop.

George

Yes, I can turn the spindle by hand with the brake off. I temporarily bypassed the float level to make sure that was not the issue. How can I check the overload? I can manually press the contactor and the spindle runs. When I press the Limit Override, the light does not go all the way off. It still burns dim. I am not familiar with the Boss system so I am not sure.
-rob

I would jump across CR3 for teseting, wire#3 to wire#213, then try it again. But you have a issue with this dim light, it should go out. One of your limit switches, the contact on CR1 or the SHUT DOWN line going to the boards is leaking ground back to the light! (I would also check the diode going from wire #126 to #116, if shorted it could supply ground the light also.)

Darek

Darek is correct in that you have eliminated the mechanical and that the electrons are not going where they are supposed to go. Thus when the contactor does pull in, it is momentary. I will hve to dig up a print and take a close look at it. Does it have the optional SCA board. The Spindle Coolant Arrest board is small, maybe 4 by 6 inches and has a silver component protruding on its end higher up than any other component.

George

perhaps bad contacts in the motor contactor, causing it to not self hold?

If I remember correctly there are small micro switches on the sides of the main forward and reverse contactors. These tell the control the spindle is ON so it will do a feed rate, they also lock out the other contactor to prevent both from turning on at the same time, and they latch the particular contactor. It is possible that one may be bad, or out of adjustment or not wired correctly.

George

I jumped #3 to #213 with same results. Yes there is an SCA board in there. Diode OK. Limit switches OK. I will check CR1 and the motor contactor. WHat symptoms should I be looking for? My brain is getting a little frayed....
-rob

If it is the latching contact you should be able to keep the spindle on by holding the switch in the start position.

Darek

Holding it in start does the same. It clicks on for about a quarter turn and shuts down and then I have to hit the limit and spindle enable again

Where are the D14 & D15 diodes located? I checked the D13 on CR1 and I noticed those other two on the schematic.
-rob

I take it the limit light is full on after this event. What serial# is your machine?
(The print I am looking at the diodes are not labeled. If I remember correctly they are buried in the wiring between the relays in the bottom of the CPU/drive cabinet

Darek

No the limit light stays dim after the event. Ser#3282

I replaced the D14 diode and that solved the dim light issue. Now when the spindle kicks then the Limit light comes back on.

I bypassed all the micro switches on the NC contacts and hot wired the forward & reverse contactors(not at the same time :)). It still makes it kick. But I can manually push the contactors and the spindle comes on... Gus mentioned motor contacts. How do I get to them on this machine? If it is like my mill/drill table then the contacts are on the back end of the motor??
-rob

The contacts on the back of the motor are for single phase starting. The auxilary contacts on your spindle contactor are the micro switches. If you are running this machine on a phase converter make sure L1 and L2 on your machine recieve the two good legs from your converter. If you put the synthetic 3rd leg on L1 or L2 your control tranfomer will not work properly. It sound like when the contactor draws the voltage on CR1 drops enough to lose the latch.

Darek

I have 208 3 phase power here. I have a small fab shop here in NC. Is anyone out there knowledgeable on this machine here in NC? Everyone I talk to so far laughs when I mention the ole Bridgeport. I feel it will be a good machine when it is done. Plus being a good learning tool. I need to get this thing making chips to make some $$. I have a couple of jobs lined up for it when I get it running.
OK - Here is where I am: So far I have changed 3 diodes and 4 transistors and I had to clean the boards. I also replaced the ACC board which had an unregulatable axis. I think I am getting closer but am stuck.(many thanks to everyones helpful input) Now when I turn on the spindle it hums and turns slightly until it kicks the overload. All three legs coming in are 120V and crossing them I get around 212V. Several months ago I had someone here who claimed to know something about these machines. He jumped something in there and it blew a fuse while the spindle was running. I had not tried the spindle since until I replaced the transistors. I think the fuses were the #4 in the back and the #6 in the CPU cabinet. I also pushed the reset on the overload. Any suggestions????
thanks, -rob

First. CR2 is a 24VDC device used to latch the spindle contactor on so if in the middle of a cut, you run of way oil, it will keep running untill you shut the spindle off. It will not restart untill you refill the resevoir.
I would consider bypassing CR3 and 5. Just make sure the air is off and brake is off.
You have good voltage measurements, but:
With machine off, I would measure the RESISTANCE, phase to phase at the spindle motor overload. note that with both contactors open, you should only be measuring the motor. This will tell you if the resistance of the motor windings match. If not then maybe one is open. This could be a bad connection such as a wire nut inside the junction box on the side of the motor. There are 9 motor winding wires in there configured to 208 VAC. You may want to do this test both top and bottom of the overload. You may have a bad heater.
Next: you may need a helper, but press in one of the contactors and measure the voltage at the overload again to ground. Have the meter in circuit, and ask someone to push in the contactor. If one pahse is missing, you need to find where.
You are very close. If I were there, this is where I would be focused.
Now to see what those fuses protect.

George

FYI: fuse 4 protects the 115 VAC output of T1.
Fuse 6 protect the +24 VDC output from the bridge rectifier.

George

There is no reason you should be losing the CR1 latch due to spindle starting (The only thing that should cause this is a limit or E-Stop switch.). It is like soming is crossed! Of course when this happens the CPU is told E-STOP and the CR3 contact in the spindle circuit should open.

Darek

Hence all that should be removed from the circuit for test. The SCA card can stop the spindle through a command from the XDI/ZDI. I have seen faulty opto couplers. Also just like a bettery, it is best to measure voltage under load. You will get a more accurate reading of what is going on.

George

Great News! The machine is up and running. I took the contactors apart and cleaned everything. I also changed another diode that was leaking a little. I guess a half bad diode:) .... Z still is not working. I have the cover off and the motor is trying but not going anywhere. I am going to recheck my voltages, current and transistors again and reclean it.
What is and where is the opto coupler?
I will keep working - still making progress...
thanks, -rob

I did haveone case where a Z axis on a BOSS 6 was giving me fits. The ZDI had a bad opto coupler (opto isolator). It does what it says. The signal becomes optical inside a device and is transmitted to a receiver. This isolates the signal and protects the board. With the Z axis; put it in step, take the belt off, try stepping it checking current and voltage. Then go to .01, then to .1, finally to continous. See if and how it runs. then put the belt back on and redo the trial. remember that the Z pulley extension with the dial cannot rub on the belt cover. Also flush the quill with kero.
Let us know the results. When you get done, you will answer all the posts on this topic!!

GTW

That is good news! Here is some links showing the opto couplers.

http://www.cnczone.com/forums/attachment.php?attachmentid=958
http://www.cnczone.com/forums/attachment.php?attachmentid=2787
http://www.cnczone.com/forums/attachment.php?attachmentid=4794

Darek

I checked the z-axis and it does 3 steps forward and one back and yep there was another blown transistor. This will be the third new one on this axis. The one that is blown was one that I replaced. I checked the static current and it is about 8.2. Any ideas what tends to prematurely blow these? I did not hit any limits while jogging...
-rob

I had a bad SMD board that was doing this. One channel out of the four was not working. There should always be two of the output transistors on at a time. When it got to the blown channel the ACC board forced the single transistor to carry the full 8.2 Amps which blew it every time. I reduced the current on this axis with the ACC adjustment to a minimum where I could trouble shoot it without blowing the transistor. After finding the problem and fixing it I walked the current back up. Make sure your machine is grounded good also.

Darek

OK I just turned down the current. How do I check to see if two are working at a time? Grounded good? The only ground comes thru the 3 phase outlet?
-rob

Any part of the base machine should make a good ground. I believe I remember a small piece of aluminum angle at the bottom of the logic cabinet where a lot of ground wires are fastened.
There are a few ways to see what is going on with the transistors. Is the Z transistor block the one behind the SMD? If not you can measure the base voltage of each transistor to see which has forward bias (turned on). Then step the drive one step and see which is on again. Repeat untill you have a truth table.
If the Z transistor block is behind the SMD, then I would go to the terminal strip at the bottom of the door. You will see connections going out to the motors. I would check Z1 through Z4 to see which is on. Step the motor, and measure again. Repeat untill you have a truth table.
BTW, this is where all the dropped screws and washers end up when they fall. Usually creating a short that mimics a blown transistor. I have seen some also caught between the diodes just to the right of this terminal strip with the same symptoms. If you find that the transistors do not turn on and off crisply (stay on half way) then one of those diodes just mentioned is shorted. Been there.

George

Hey, I am back. Been making a few chips which justifies this machine:) I am still having trouble with the z-axis. It keeps blowing the 3rd transistor down. I lowered the voltage as instructed but it immediately blows the transistor. I put another SMD board from another axis but with the same result. When I got the machine the z-axis would travel a little and then stall -- I noticed all the diodes on that board were disconnected so I soldered them back up. I have not had the z-axis back up working since. I do not know how or why the diodes would have become disconnected... Does anyone know what this would be indicative of?? Help... The z-axis is very helpful....
-rob

Look at the terminal strip below the SMD boards. Make sure all wires are tight and that there are no screws there that do not belong. They usally look like the screws that hold the transistor blocks. I wonder why.
If I was there, I would be comparing the Z to the other two axis. Checking every voltage that I can.
As a last resort, I would swap the Z motor with the X or Y. If the problem follows the motor, then you have an answer. There were two different motors used on these machines. Some were made by Sigma, others by Superior.

George