Heidenhain TNC113/FP1 bellows

Evening chaps.
My late model FP1 aktiv has had issues with the DRO since I bought it. It worked initially, then started flashing on each axis screen, now its totally dead. Friend of the family is a Heidenhain engineer, they only support systems for 20 years apparently so he's no help. Franz Singer sells an exchange unit - I'm guessing this is the easiest way to solve my problem?
While I'm ordering from singer I need new bellows for the Z axis. Are the metal "samurai looking" ones a sensible choice while I'm doing it? Do they need any other parts or are they a straight swap?
Thanks in advance!
Tom

I've fixed three Heidenhain DROs. In all three cases, the problem was with the power supply, and was easy to fix and cost just a few Euros. In one case a 3-pin TO-3 package voltage regulator needed to be replaced, in another case some electrolytic capacitors needed replacement, and I've forgotten what was wrong with the third. So if you have some basic electronics skills you might be able to fix it yourself in an afternoon for very little money.

Thanks Bruce. Complex (read - more than rewiring a contactor) electronics are really not my thing. I guess I have nothing to lose so I'll open it up and take a look!

Does anyone have any thoughts on replacing the bellows with the metal ones? Worthwhile upgrade or not?
Thanks

The TNC113 on my FP2 did exactly the same thing. Started flashing then went dead. I have not repaired it yet so hoping you don’t exchange it but are able to figure out what happened and report back here.


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Tfrench said:

Thanks Bruce. Complex (read - more than rewiring a contactor) electronics are really not my thing. I guess I have nothing to lose so I'll open it up and take a look!

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I am pretty sure that these have classic "linear" power supplies that work as follows. Power comes in at line voltage/frequency, and passes through a power switch and transformer. It's very unlikely that anything is wrong there. But with a multi-meter you can check that the transformer has 230V AC across the primary side. If needed, spend a few minutes reading about transformers on the internet.

The secondary side of the transformer has several windings. These provide lower voltages, for example 6 or 12 volts AC. Again, it's unlikely that anything is wrong here. That lower AC voltage is then sent through a device called a bridge rectifier, made from four diodes, that converts it to a DC voltage that is about 40% higher than the AC one. Each of the windings will have its own rectifier. One or more of these diodes may be burned out. If so, you may see/smell damage to it.

Again, you can read on the internet about how a "full wave rectifier" or "bridge rectifier" works. It's not hard to follow. It's also easy to test the four diodes (often contained in a package with four pins) with a multimeter.

The DC voltage from the diodes is then "smoothed" by some electrolytic capacitors. These can dry out after decades and fail. Your eyes and nose can sometimes sense this, sometimes not.

Finally, the DC voltage from the capacitors is often reduced and tightly controlled by voltage regulators, that are often three-pin semiconductor devices with a ground pin, and input pin, and an output pin.

In total, there are probably three or four different voltages produced in this way. Often they are labeled on the circuit boards as VCC or V+.

If you have a cheap AC/DC multimeter and some patience, you can identify and test the different power supply output voltages. If something s wrong, none of the main components (apart from the transformer, which is probably just fine) costs more than pocket change, so can be swapped.

Do you have a local ham radio club? Or an electronics club at a local school or university? Either of those should have people who can easily do this or show you how.

Does anyone have any thoughts on replacing the bellows with the metal ones? Worthwhile upgrade or not?

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Personally I prefer the fabric ones because they take up less of the Z travel. Unless they are torn or otherwise defective, I don't think it's worth replacing them until they fail. At that time, if you don't mind losing the vertical travel, then go with the metal-armoured ones.

Cheers,
Bruce

EDIT: I just looked on-line and found a service manual for the TNC 113.

Service Manual TNC 113

If you look at Section 4.5 it shows the input and output voltages of the power supply. Suggest you test these with a multimeter. Be careful not to touch line voltage wires, 230VAC can hurt you or kill you.

I don't know about the OP buy my unit flashed for a while, like maybe 2 minutes or more, before it went dead. Like a battery was dying, or maybe it just takes that long for the power supply capacitors to discharge. Is there a battery in these units anywhere?

adh2000 said:

Is there a battery in these units anywhere?

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I don't know, but the service manual above makes no reference to a battery. Open it up and check the voltages at the input and output of the power supply board.

If you do not have it you need a support for the Z axe bellows
Anschlagleiste gebr. fur den Z - Balg FP1 der Deckel Frasmaschine | eBay
That will knock out powerfeeds earlier
Give Singer your machine# when ordering

It's now my turn to experiment problems with the TNC113 of my FP1...
I have domestic three-phase and it is a 220V machine so it is powered via a 380>220v transformer.

It worked flawlessly until yesterday but now the TNC shuts down and re-starts everytime I turn the spindle motor on on high speed...
It's my understanding that the starting of the motor, especially in high speed, causes a current draw and a voltage drop.
The TNC doesn't seem to be happy with that.

Remembering the piano lessons I took in my early days, I managed to start the machine in low speed then switch the motor to high speed before the spindle stopped, without affecting the TNC.
I checked the motor connections and looked for any abnormal drag in the motor or drivetrain. Everything seems to be ok.

Funny thing is if I hook the readout to a socket of the shop rather than through the electrical cabinet of the machine, I can start the motor in high speed without problem.

Are there components in the TNC power supply which ageing, could alter the ability of the readout to withstand the electrical perturbations due to the motor starting ?
Do any of our resident electric/tronic gurus have pointers about what to look / check ???

TNB said:

Do any of our resident electric/tronic gurus have pointers about what to look / check ???

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Your experiment: hooking the TNC to a shop outlet instead of powering it internally, is very revealing. As you say, it means that the internal voltage is dropping below the limit.

I have a couple of questions... you have 3 phase 380V in the shop, and that's going into a 3-phase transformer, which then provides 220V 3-phase which powers the machine... is that right? So the 220 3-phase is 220 between any pair of the 3 hot lines? If so, your TNC is powered between two of the hot lines, say 1 and 2. So try powering it from the other two possible pairs, 1 and 3 and 2 and 3.

A second solution is to add a current-surge limiting NTC thermister into the circuit (in this case the spindle drive) which is drawing too much current.

A third solution: open up the TNC113 and replace the electrolytic capacitors, which are probably drying out with time. Those provide the electrical current during the brief dip in the line voltage, and probably have lost much of their capacitance. The fact that this problem is now present but was not there before, points a bit in this direction. Capacitors do age and lose their ability to store charge. So it would explain why the problem has now appeared.

Last solution: investigate the power cabinet and see if there is a component or wiring there which is responsible for the excessive voltage drop. But that may be hard to locate.

ballen said:

A third solution: open up the TNC113 and replace the electrolytic capacitors, which are probably drying out with time. Those provide the electrical current during the brief dip in the line voltage, and probably have lost much of their capacitance. The fact that this problem is now present but was not there before, points a bit in this direction.

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That is exactly what I was thinking about...
Thank you so much for your input Bruce !

ballen said:

If so, your TNC is powered between two of the hot lines, say 1 and 2. So try powering it from the other two possible pairs, 1 and 3 and 2 and 3.

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I suppose the result should be exactly the same assuming the motor functions properly (i.e. each winding drawing the same current), right ?

I would hook up a amp clamp on the motor first
See if all 3 phases are the same amperage
If not investigate the motor (smelling first) )
Check if the brake is disengaging is another one

Peter

TNB said:

I suppose the result should be exactly the same assuming the motor functions properly (i.e. each winding drawing the same current), right ?

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In principle that's probably right. In practice though it may not be. So if it's easy to swap the TNC113 power input to other combinations of the phases, that might be worth trying.

Note: if you own or can borrow an inexpensive four-channel storage scope (Rigol DS1054z, Siglent 1104x-e, ...) you can hook one channel to each of the three phases and make a plot of the voltages when the spindle is turned on. Then you would see exactly what is happening and there would not be any need to speculate or guess.

PS: Peter might be right to suspect the spindle motor, he has much more experience than I do.

ballen said:

PS: Peter might be right to suspect the spindle motor, he has much more experience that I do.

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Not expeience in electrical equipment
Always check the obvious first
In a normal outlet it functions properly
When you start the motor at high speed it stalls
So motor is suspect no 1
The easiest way to check a motor is with a ampprobe

Peter