Largest Manufacturing Technology Community on the Web
Stay Connected:
Heidenhain Positip 850 Help Required
- Thread starter adrian
- Start date
- Replies 51
- Views 6,523
DeadMahoDude
Aluminum
- Joined
- Oct 30, 2016
Fitting went rather easy for me, piece of plywood as backing plate for isolation and 4x2holes for a couple of zip ties. 
Assuming it's the switch mode supply that you need, an open frame power supply will do the job.
The difficulty is finding a small enough unit to fit inside the Heidenhain case.
It needs +5V -5V +12V and -12V supplies at relatively low current, probably a couple of amps per voltage.
These units are still made by specialized companies for use in third party equipment but will be expensive.
Best have a trawl through eBay for a new old stock item. I found one in Germany but that was some years ago.
The difficulty is finding a small enough unit to fit inside the Heidenhain case.
It needs +5V -5V +12V and -12V supplies at relatively low current, probably a couple of amps per voltage.
These units are still made by specialized companies for use in third party equipment but will be expensive.
Best have a trawl through eBay for a new old stock item. I found one in Germany but that was some years ago.
Thank you Adrian. I looked for those voltages, I assume in ac, but don't get any of them on the wires on the board on the right. Does that mean it's that board that's bad or the one on the left? I get no voltages on the connector that's at the top on the board on the left.
The voltages quoted above are DC.
Enclosed is a photo of the original Heidenhain power supply. The two wires outlined in red are the 240/110V AC input and those outlined in blue are DC outputs.
With no outputs the first thing I would check is the fuse adjacent to the AC input.
When these power supplies fail they generally loose one voltage rail not all.
Enclosed is a photo of the original Heidenhain power supply. The two wires outlined in red are the 240/110V AC input and those outlined in blue are DC outputs.
With no outputs the first thing I would check is the fuse adjacent to the AC input.
When these power supplies fail they generally loose one voltage rail not all.
Attachments
I wouldn't worry too much about missing components, pcb's often have option parts not required, more important to look for any burnt out damaged components.
The voltage colours are shown in the attached photo in my reply on the 22th April on the left hand side.
It shows the small linear power supply voltages and switched mode unit which is 0V black, +12V brown, +5V red and -12V yellow.
The drawing on the right was the pin out of the replacement supply I fitted and not of much use to you.
Working a a switch mode power supply is not for the faint hearted and to be honest unless you have the technical skill and test equipment required it's best to find a replacement.
The voltage colours are shown in the attached photo in my reply on the 22th April on the left hand side.
It shows the small linear power supply voltages and switched mode unit which is 0V black, +12V brown, +5V red and -12V yellow.
The drawing on the right was the pin out of the replacement supply I fitted and not of much use to you.
Working a a switch mode power supply is not for the faint hearted and to be honest unless you have the technical skill and test equipment required it's best to find a replacement.
ballen
Titanium
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
Now that you have checked the fuse and confirmed input voltage, the next thing is to check that you have about 170 VDC on the large capacitor in the middle (the black one that says 400V 100uF on top). But be careful, that voltage can easily kill you!
ballen
Titanium
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
The diode bridge is the small black item with four pins. It should have 120ac across the two pins with wavy lines, and 170DC across the +- pins. Does it?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
ballen
Titanium
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
The 170 dc should connect directly to the 400v 100uF capacitor. Why do you not see the same voltage there?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
ballen
Titanium
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
You're welcome. For the next step you need an oscilliscope.
At the bottom of the middle compartment is a little coil sitting on a green pad. That's the high-frequency transformer,
which is converting a chopped version of the 170 VDC into a lower voltage higher current signal. You want to first
connect a scope across the fine red wires, which are the high-voltage input (primary). You should see a roughly sinusoidal waveform at something between 50kHz and a few MHz. (Any online users know what frequency this runs at?) Then you should check the low voltage side, which is the thicker wires, where there may be several pairs. There you should see a sinusoid at the same frequency, but lower voltage.
At the bottom of the middle compartment is a little coil sitting on a green pad. That's the high-frequency transformer,
which is converting a chopped version of the 170 VDC into a lower voltage higher current signal. You want to first
connect a scope across the fine red wires, which are the high-voltage input (primary). You should see a roughly sinusoidal waveform at something between 50kHz and a few MHz. (Any online users know what frequency this runs at?) Then you should check the low voltage side, which is the thicker wires, where there may be several pairs. There you should see a sinusoid at the same frequency, but lower voltage.