Haas vf1 not powering up

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 23, 2017

• #1

Alright 1st time post so bear with me. I have a 91 haas vf1 with a problem powering up.

Symptoms are as follows:
Press green power on button machine will start up but as soon as you release the power button it powers down. If you hold the button depressed the machine powers up fine with no alarms. When button is depressed the k1 relay is working and the halt light is off. Prior to this the machine has been running smooth for aprox 7 months.

Things I've checked so far:
In coming voltge from phase converter
Checked all fuses
Replaced k1 contactor
Check 24v at overvoltage board
Looked at all the relays ( not sure how to replace them as they are soldered to the board)

Looking for some info as to what I can check on the 24v side or the k1 circuit. It's like the circuit isn't holding the power and dropping k1 relay.

Any help would be much appreciated.

Thanks

 

M

machineit2

Hot Rolled

Joined

Jan 21, 2011

Location

Tennessee

• Jan 23, 2017

• #2

When you hit the power button, it puts power to a solenoid in the main breaker that engages the current to the machine. Once it is engaged, it is supposed to stay on using a different circuit inside that breaker. It should not drop out again until it is interrupted, like with the power off button. It seems that the circuit that keeps in on is bad. There is likely a set of points inside the relay that completes the circuit. They could have gone bad and are not making contact. Or, maybe your power off switch is stuck!

Make sure to disconnect any power to the machine before digging into it.


Mike

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 23, 2017

• #3

Thanks for the info. I will check the power off switch tonight.

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Jan 23, 2017

• #4

The main contactor should be a "latching" circuit. So basically the way it should work is that you push the power button and that powers the coil of a relay or contactor or combination of both. As soon as that contactor or whatever closes, it closes a circuit that provides another source of power for its coil.

Do you have a wiring diagram? Can you host a picture of it on google docs or somewhere? I'm sure if I could look at it we could get it sorted out.

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 23, 2017

• #5

Yup let's try this link. Thanks again guys.

Untitled document - Google Docs

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Jan 23, 2017

• #6

OK. It's a latching relay. Basically, we need 24V from either side of that center tapped transformer to pass through the K1 coil. The coil is indicated by the K1 with a circle around it.

So, when you push the "on" button, it sends voltage to the K1 coil. Then the K1 contact closes and supplies power to the K1 coil. At that point you can release the button and the contact stays closed. That is a latching contact.

With the power turned off, you need to check for continuity between wires 743 and 744. This will test that the "off" button is closed. Then check continuity of 67 to 172. That will check the K7 relay. K7 is normally closed and has to be open for the thing to work.

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 23, 2017

• #7

Ok tested wires 743 & 744 and have continuity. I could not locate the other wire labeled 67 & 172 ? I have attached another link with pictures and a quick note on what I think I should be checking

Untitled document - Google Docs

Thanks

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Jan 23, 2017

• #8

13 and 14 are the coil for K7. That's not going to tell you anything.

I don't think it matters though. If you hold the button and it powers up OK, that tells me that something must be wrong with the latching contact on the K1 relay.

Can you swap the K1 relay with another relay and see if it powers up correctly?

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 23, 2017

• #9

As far as I can tell the relays are soldered to the board so I don't think I can remove them without soldering the pins.

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Jan 23, 2017

• #10

Your problem has to be in the section of the circuit I colored red or it has to be related to the K7 relay.

The only way what you describe can happen is the K1 relay is not latching itself through its own contact, or the K7 relay is changing states when the push button is released.

You might have to do some testing with the power on. Just be careful and try to get a helper.

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 24, 2017

• #11

Update:

After Turing on the machine several times last night and testing voltages I now have the following alarms: 161 X axis over current and 170 phase loss L1 - L2. I'm starting to suspect the IOPCB Board. Any thoughts on this ? I also noticed that some resistors looked like it got hot at one point. R76 , dz1, dz3 all look like they got cooked on the 880/890 circuit.

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Jan 24, 2017

• #12

Are you sure the incoming power is OK?

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 24, 2017

• #13

Voltage measured 235-242 across the legs? Dc bus voltage was 171. I had two electricians out last night to double check the power. And go over any possible component failure. The 161 alarm would only come up during powering the machine off ? But the 170 don't clear after a reset and it has never done that before.

 

B

Bulltrout

Plastic

Joined

Jan 23, 2017

• Jan 24, 2017

• #14

The machine has been hooked up and running off of a American adx 20hp phase converter. Also after we made all the connections I paid haas to come out and double check the voltage taps , over all install and had them level off the machine and get it functional

 

B

bill mccandless

Plastic

Joined

Feb 24, 2006

Location

greensboro, nc

• Jan 24, 2017

• #15

Power up

Check for a gummed up STOP button first. they get stickey from finger grunge and may be stuck open.

Bulltrout said:

Alright 1st time post so bear with me. I have a 91 haas vf1 with a problem powering up.

Symptoms are as follows:
Press green power on button machine will start up but as soon as you release the power button it powers down. If you hold the button depressed the machine powers up fine with no alarms. When button is depressed the k1 relay is working and the halt light is off. Prior to this the machine has been running smooth for aprox 7 months.

Things I've checked so far:
In coming voltge from phase converter
Checked all fuses
Replaced k1 contactor
Check 24v at overvoltage board
Looked at all the relays ( not sure how to replace them as they are soldered to the board)

Looking for some info as to what I can check on the 24v side or the k1 circuit. It's like the circuit isn't holding the power and dropping k1 relay.

Any help would be much appreciated.

Thanks

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