Heidenhain tnc 2500B help

[alexandermatovu]

I have been handed a Bridgeport interact 1 mk2 with an Heidenhain tnc 2500B controller, it hasn't worked for 6 years. when i turn on the power the green light on the machine goes on however the MDI/CRT does not go on.
Please help!!:

[machintek]

The typical set up on a TNC2500 is to have 2 24VDC power supplies. One powers the control, the other all the relays. Check those first. Needless to say, you will need all the books.

George

[alexandermatovu]

Thanx goerge. I have measured the power from psu1 and psu2 and found out that its way below 24V. What should i do? Is there any alternative? I need to get this machine up and running.

[awemawson]

Originally Posted by alexandermatovu Thanx goerge. I have measured the power from psu1 and psu2 and found out that its way below 24V. What should i do? Is there any alternative? I need to get this machine up and running.

Specifics!!! Give specifics - you've measured the supplies what ARE the measurements?

[machintek]

You may have an excessive load on the low power supply. Remove the load and see if it comes back. If so, you should measure the amps to see if that is excessive.''

George

[alexandermatovu]

psu1 gives out 19V and psu2=0.5V . I don't understand which loads to remove,George.
Is the psu adjustable?

[awemawson]

OK PSU 2 sounds as though it's gone into protect mode firing a crowbar circuit across the output. As George says with the power off disconnect the output of the power supplies and then power them up and measure again. Be aware that the psus may use 'remote sensing' where the feedback connection is taken to the load at the far end of the output cable. If this is the case when you disconnect the output at the psu you will need to strap the sense connections to the o/p There will be terminals marked -S and +S possibly adjacent to the -ve and +ve output terminals.

Make sure that these psus are getting the correct input voltage - again measure and compare to what it says on the psu.

[machintek]

I believe the input to these power supplies is 220VAC and uses red wires. I have removed the blue output wires to see if the power supply returned to 24VDC and they did. If the errant power supply does come back up to 24vDC after the blue wires are removed, I would suspect a short in that circuit that needs to be found and eliminated/repaired. Otherwise the power supply may be bad. I have replaced many of these. They do go bad.

George

[Harmeet]

the power supply is bad if after removing the load wires it doesn't show 20 to 24 VDC. Replace if they r not showing. if its near 19 V as u told it can be adjusted with help of a variable resistor on the power supply itself. Replace the faulty power supply.......
Check again and if the screen doesn't still ON than check for the safety relay..
there are two safety relays on the relay board they should show grieen light if all the safety circuits are ready..
check for the safety relay on the relay distribution board..... it should go green.