-90 VF1 Rebuild

Hi All,
First posting. I bought the VF1 with a few known issues and several unknown ones. I think the last time it was cleaned was '91? It appears to have been maintained by a shade tree mechanic. There were several parameters changed or disabled. I took out 5 gallons of steel slivers stuck to the inside of the cabinet and under the way covers. They were using oil instead of coolant which stuck the slivers everywhere. The oil did not keep the underside of the way covers from rusting or the ends of the ways that were rarely used. I bought one of the China Freight electric pressure washers to blast everything. It works fine, no problems and has saved a lot of time.

Anyway, first problem was the screen, too dim to read except in the dark. It also had been replaced at some point and another chassis was bolted in place. I took the CRT out of a Digital VT220 and replaced it with that. Now it is readable but there are lines on the left from the beam wraping to the next line. For now I will change out the CRT driver board with the VT220 board which I am sure is a better quality. When I have more time I will make an LCD replacement.

The Y axis had an intermittant over current (known issue). When jogged at 0.01 the Y alarmed out but ran fine at slower speeds. The X axis did not run at all with an over current alarm (unknown issue). I pulled the servos and found the inside of the brush caps packed with carbon. Whoever rebuilt the Y servo did not put the O-rings back in so there was oil inside the servo. The X cable casing was broken in three places between the table and the back of the cabinet. I cleaned the carbon out with brake cleaner. The brushes were fine. It still had the same problems and I could see sparking in the brush area through the wire hole. I was quoted $750 as a start for a rebuild. Seems a bit steep for a simple DC motor. I went back in and cleaned between the commutators of the Y servo and thoroughly washed down the armature and commutator with brake cleaner ($2.99). Now the motor worked without alarming. I put the Y servo on the X cable and it works, so the wires are fine, I just need a new casing.
Doing the same with the X servo did not produce the same results. I found inside the cap that one of the brush holders had crumbled near the wire connection, probably from the heat of arcing due to the carbon. The servo still over current alarmed. I then checked the resistance between the motor wires and the case, 350 Ohms. Taking out the brushes one by one I found two opposite brushes were the problem. These were connected together and one was the crumbled holder. To determine if it was the armature or the brush cap I measured between the brush holders and the case. The holder was the problem. I tried replacing the brush cap with the one off the Y servo and the motor worked fine. So I have to get another cap or holder. I presume these are glued in place?

The door on the ATC was held open with a piece of cardboard wedged under it (unknown issue). The pin that moves the door is missing. The original was just a steel pin, fortunately I have a 1/2" cam track bearing so I only need a bracket to mount it. I will add the nylon buttons to the door as a bearing slide. One door on the tool holder is stuck open. I have to take off the cover to see if it is just chips or something else. The tool changer has some slop on the V rails. Both the eccentric adjusters are fully in. The post that holds the upper right V bearing was broken off and replaced with a piece of bar stock. Both the ways have wear, especially at the ends of the stroke so they will likely need replacement. The cable casing is broken. Has anyone used the high flex casing from McMaster? It may be more durable than the Carflex.

I could not get the spindle to orient, the tool release or high gear to work (unknown issue). I had 80 PSI at the compressor. The manifold block behind the spindle motor was hanging by the copper lines from the gear changer. I made a mount for the solenoids and attached it to the flex conduit holder. After cleaning the air actuators and increasing the pressure 90 PSI the tool release and spindle lock worked but the gear changer did not. I put 110 volts AC on the solenoid and the air actuator worked. Measuring the low and high signal at the connector and got nothing. I tried measuring the voltage across the low and high gear LEDs on the I/O board and still nothing. I am still not sure if it is a parameter that I have not found or a problem upstream of the I/O board. A friend said it could be one of the high/low switches are stuck. I will have to go back and move the air actuator using 110AC at the plug and see if the switches read it.

The top cover is split at centre front. It has a piece of aluminum plate bolted across the split. I will have to come up with a more secure re-enforcement. I noticed on the '91 VF1 rebuild posting there are two brackets with a short 45° at one end. I do not have these. Are these supports for the sides at the bottom or top? The lower corners at the rear do not fit very well so I am wondering if the cabinet is sagging. The operator light was hanging by the wires. For now I will replace it with an automotive fog light that I have.

That is it for now.

I found brush holders at carbonbrush.com, $45. They are held in by a set screw. The wire has a clip that is pushed in between the brass insert and plastic holder. After removing the holder I could see the eroded part of the holder went down to the cap hole. It probably is packed with carbon and caused the short. A new R10 bearing for the rear and O-rings and the X servo will be good to go.
I need to machine the ATC housing. The V bearing stand-offs have distorted the aluminum posts. I will machine those flat and put in a steel washer to spread the load. The back of the housing has grooves from the in/out servo arm so I will machine that for more clearance. The wires had crimp terminals bolt and screwed together with electrical tape around them. I will put proper connectors on these.

Were are you at in Ca.? I have 5 mills of this vintage (4 currently running) and the problems you see are normal to wear and sloppy repair work.

I just had 4 motors rebuilt to the tune of $3500. from a place in San Diego, if you need contact info PM me.

Standard course of action for us is to replace both x an y cables and be done. Were using Liquid Tuff from the box store instead of car wrap or even the stuff that come with the new wire sets. We found after about 6 months it cracks and splits and allows the coolant to attack the wiring sheathing then your back in the same boat.

There is a hi gear/ lo gear parameter and you want to make sure it's a 1 to be on. If it is a 1 the you still don't shift odds are the shifter mechanism is toast. You have to pull the spindle motor off to access it so it's a replacement for us as we don't have the time to mess around. I cleaned one and reinstalled only to have it go out again a few weeks later so that was a double headache we didn't want to have again.

There are a couple rebuild threads in this forum that you may want to dig out and read as there good info and some good pics to see where stuffs at before you pull it apart.

Good luck!

Thanks, I looked through the '91 rebuild thread and that is where I saw the brackets with 45° bends. From an assembly drawing I believe these are supposed to be on the upper row of screws between the side and back.
I should have the servos under control. I tool the Z servo apart and cleaned it as well. After playing around with the gear shift I got a Z over current alarm. The Z servo is different from the X and Y. I later found the Z alarm was due to one of the ribbon connectors. I will have to go through all the connectors and reseat them.
I know the gear air solenoid works, I put 110 VAC at the connector and was able to move it between high and low. The switches are also working. On the diagnostic page the input SP HIGH is 0 and SP LOW is 1 but the outputs for HIGH and LOW are both 0. I put a meter on the I/O board and found there was no signal at the relay with both M41 and M42 commands. Checking back at the motor interface board there is no signal at the connector. I checked the tool unclamp output to be sure that I could read the signals. So it appears the problem is in the motor interface board. The gearbox is enabled in the parameters.
The X cable has the 90° elbow at the table feed through. I should only have to replace the conduit from the elbow to the panel. McMaster has an Ultra flex conduit that looks like the existing black conduit but it says for "periodic flexing". The also have a heavy duty type B which is slightly cheaper and "continuous flex" type A at four times the price of the Ultra flex. They are all PVC so I am not sure the life will be any better with the expensive over the cheaper conduit.
I am in T.O. (west of LA)

"I need to machine the ATC housing. The V bearing stand-offs have distorted the aluminum posts. I will machine those flat and put in a steel washer to spread the load. The back of the housing has grooves from the in/out servo arm so I will machine that for more clearance. The wires had crimp terminals bolt and screwed together with electrical tape around them. I will put proper connectors on these."

You may also find they need heli-coils, I had one bad there and all four for the tool carousel drive motor. Maintain the original post height! The groove is most likely from all the slop in the failed bolts/bearings/rails so I would not bother machining the back. When in proper form this assembly moves freely with no slop. Invest in new V rails if worn/damaged, stud axles and bearings are most likely in order.

Ha, your cables at least had crimp connectors, mine were simply twisted together and had the suggestion of tape. Nothing wrong with crimp connectors - if you use high quality parts and tooling.

Don't scrimp and try to save pennies on the ATC assembly by, once refurbished it will last thousands of hours and cycles.

Good luck, post pictures!

Regarding the X-Axis cable. Since the outer sheathing has been compromised causing it to become brittle and crack, then most likely the wires inside are also compromised. Even if they don't show signs of cracks, I would not trust them to last long term.

IMO, I would either replace the cable with a new unit from Haas or build your own out of higher quality materials.

Good luck with the rebuild!

I realize the ATC has to be located correctly to the spindle. I will measure the thickness of the washers and machine accordingly, thanks. The V rails show wear and it appears there is no adjustment to them so all the adjustment has to be with the eccentrics. The V groove bearings are on bolts, are there supposed to be axles of some kind?
I will check the wires after pulling out the cable
I need Y way cover scrapers and Orings for the support rollers, probably why there was so many chips behind the cover.
Here is a couple of pictures after a lot of cleaning:

Sounds like your down the street and around the corner from me..i'm in Chatsworth.

The x cable is the bitch getting it thru that bend in the table. Use lots of soap and she'll slide thru but not without a bit of effort. Were using the Liquid Tuff and it seems to be working good without cracking and leaking, i'm not familiar with the stuff from McMaster.

Check the shaft on the shifter and make sure there isn't excessive wear on one side of the shaft. If it's worn it's best to replace. Also make sure you torque the mounting bolts when re installing. This will prevent further wear on the shaft as it has a tendency to lean when moving up and down.

Good luck.

Wow your machine looks worse than mine did, plastic scraper and a bail of rags! A narrow tile cleaning brush from the Blue or Orange store holds up best.

I figured you would understand the idea of maintaining the height, I tend to state the obvious sometimes. The V upper bearings are on a shoulder bolt, the lower on eccentric shoulder bolts, I used blue locktite when installing them.

Keep up the good work!

The ATC now fits tight on the rails but I will get new ones as these show wear marks at the ends of the travel. A friend is picking up a motor interface board for me to swap out. I tested the I/O board by sending signals down the 520 cable for low and high gear. The I/O board LEDs worked, the air solenoid moved and the switches showed the position. I also checked the signals going to the SN75468N drivers on the motor interface board and got nothing there. That would have been a cheap fix.
One thing it does not do is oscillate the spindle when changing gears. In the mean time I am cleaning and I pinned out the X cable since I have to remove the connectors to pull off the casing. Here is the wiring diagram if anyone needs it:

There are two white wires on the encoder that do not appear to have a second colour. This cable has a 90° non-splitable shell on the computer end. Both the Y and Z have a removable back. I will pull one of those open to see if there is a second colour to those white wires. And yes, the J pin of the MS connector is wired to the WT/RD encoder and WT temperature sensor. Odd since there are 14 pins in the MS and 12 connections at the servo.
Sometimes the obvious is overlooked
I checked the cable at the computer end and found all the correct colours. Updated the atachment.

Do you have this?

Haas Automation® Resource Center | Your Source For Routine Maintenance, "How To", Manuals & Documentation, Repairs & Service and Drawings & Diagrams

Thanks, yes. A friend just sent it. Something that I noticed in there probably answers a question that I had. When the machine is running but not moving, the servo regen load resistor was glowing. The buss measures 160VDC so I suspect R2 on the servo distribution PCB is out of adjustment. It should not turn on until the voltage reaches 183 to 187 VDC.
A friend lent a MOTIF board to try but the machine did not boot up. Either the board is bad or the wrong configuration.
Since I had the MOTIF board off, I looked at the processor board. I have one blank row above the three rows of ROM chips, then one row of RAM and another blank row above that. The lower blank row is labeled ROM/RAM and the upper row is labeled RAM. I was told that Hass wants $5k for a memory upgrade. I found a supplier for the chips, $2.49 each. I do not know if it requires a parameter change or hard coded software but it might be worthwhile to find out.
I bought flex hose casing from McMaster so I will find out how long it lasts. I also needed O-rings for the servos and button head socket screws to replace the Phillips screws around the outside of the cabinet.

You seem far advanced on the electronics of the machine than I will ever be. If I can't fix it with a hammer and pliers its an electrical problem. Fortunately I have people.

For the memory, there was this post: http://www.practicalmachinist.com/vb/haas/adding-memory-vf0-164239/

If you can make it work I would be interested in hearing it.

I bought a used MOTIF board to try, same alarm when I try M41/M42, spindle turning. The spindle does not move before the alarm. I had to increase the spindle speed parameters with the second MOTIF board to get the spindle orientation to work. Otherwise the spindle only turned about a quarter revolution. I saw a voltage on the analog VFD input during an S command and spindle orientation but not on a gear change.
I think the problem might be the VFD is not sending the spindle stopped signal back to the I/O board cable 780 header P21. The wiring diagram only shows three connections: spindle drive fault (P21-1), spindle stopped (P21-2) and spindle at speed (P21-3). Cable 780 has five wires: black, white, red, green and black. Black could be ground and red +12 volts but the black, white and red are on pins 1, 2 and 3. Any insights?

I made a break out cable for the 780 connection. Disconnecting the first wire (black) gives a spindle drive fault, the second (white) gives a spindle turning fault, the third (red) gives nothing, the fourth (green) gives spindle drive fault again and the last (black) gives nothing. I suspect the last is a ground reference since it measures zero volts relative to ground. The I/O board black, white and red wires measure 0.72 volts when connected to 780 and 11.5 volts when disconnected which indicates the I/O board is probably working. If I disconnect the red wire and command M41 from high or M42 from low, the spindle turns, gearbox shifts and the spindle stops. According to the wiring diagram this is the spindle at speed feedback so the VFD thinks that it is not at the commanded speed.

I received the Y cover wipers, ATC rails and nut for the ATC spindle from Haas. I found the lower rail had one broken bolt, one hex bolt (apparantly hex sockets are too expensive?) and one 6mm bolt. Somehow they managed to strip the thread in the plate, drilled it out and used the metric screw. I could not find the 1/4-20 Helicoil tap so I had to use a Time-sert.
After reading the thread on the '91 rebuild, I made delrin buttons for the ATC door. They had a piece of wadded up paper holding the door open and the door drive pin is missing.
The geneva wheel had three slots gouged out. I welded the slots and remachined them. The wheel is very hard and burned up three HSS cutters. It would have been cheaper to use a carbide bit.
I repaired the damage to the X servo cable where it goes through the table. The flex conduit was broken in three places under the table and the cable sheath was split where it worked against the fitting. One power wire was damaged. Instead of cutting all the wires and splicing I cut back the cover, soldered aross the damaged wire applied liquid tap, heat shrink around the wire, another heat shrink over the open span of outer sheath and another extending over the outer sheath. The repair is inside the table elbow so it will not be bent when the table moves.
Now to clean under the covers of the tool wheel. One door was stuck open from all the debris.

You may find the small screws on tool carousel covers very stubborn. I used a 200w soldering iron to encourage them as they appeared to be installed with blue loctite.

I have the ATC back together. I found the easy way to install the wheel is to put in an all-thread stud on the axle then lift the wheel on to the stud, put on a nut to hold it there, then put in the bolts. Otherwise trying to hold the wheel up with one hand and fishing around with a bolt to align it was too difficult. I put connectors on the wires that were bolted and wapped with electrical tape.
I put connectors on the Y servo motor and re-installed it. They had the wires soldered in place. The Z axis covers are on and the rear Y cover, installing the rest of the covers except at the X servo, still waiting on the brush holder.
I found the easy way to pull the wires through the flex conduit was to feed a nylon string (the one supplied by the big box stores for tying down your purchase) through the conduit and tying it around the wires. Add a piece of heat shrink over the ends of the wires keeps them together. Tie the loose end of the string to a post then pull the string tight with the wires and pull the conduit over the wire bundle. Do not forget the cable nut and conduit seal before pulling the wires through. Note that you have to have the wires uncrossed before pulling because the ferrule diameter is too small to allow the ground wire to be moved around the power and encoder wire casings.
Feeding the wires through the 45°/90° table elbow was fairly easy. I used a piece of 14 gauge solid wire fed through the elbows to get the string through. Then it was just feeding the wires as I pulled on the string.
To keep the X cable, X home wire and oil feed tube from tangling or wearing I wrapped them with nylon spiral wrap. I check the cable position at both ends of the Y axis travel for clearance.
I checked the operation of the ATC. The wheel hits the tool a little high and the spindle pushes down on the wheel when picking up the next tool. Haas said this serial number was made for CT40 but the previous owner said he only used BT40 and CT40 did not work in it. I would hazard a guess that someone changed the Z parameter and it does not fit either exactly but is closer to BT40.

Nice job with everything so far!

The fingers on your tool change will dictate if it is CT or BT, they are not interchangeable. The configuration of the locating key is different also.

Thanks haastec. The fingers on my wheel are 0.240" thick which barely fit within the CT40 vee. I noted several differences between the BT40 and CT40. The alignment notch is 0.625" and symmetric (BT) vs 0.645" and assymmetric (CT), wider/deeper vee 0.180"/2.010" diam. (BT) vs 0.155"/2.220" diam (CT).