Uher SG-630

[paul_ral]

I have a Uher SG0630 Logic on the bench now, I found a missing fuse on 2000 board and no belts inside. I put a new fuse and the only thing is working is a red led for recording. I ordered new belts from Germany and I replaced all capacitors, tantalum too. Now I have the capstan motor running but no changes in switches action, it is stuck on recording. Is this issues related with computer board or could be anything else like K1, K2 or K3 switches. I clean all contacts and they are looking good.










Thank you for watching!
Paul

[JumAC]

I had a similar problem with my SG 630.





It turned out to be a problem with head bridge plugs and contacts.

The plastic holders were broken, so wires got a short to head bridge housing.
First check this and if so, do repair of both plug and sockets using 2-component glue.

Following this short, transistors T1 (sometimes) and T2 (always) on print 1500 had gone defect.
Sometimes the fuse of +20V was blown too.
Check signal 1554 "Aufnahme +20V", which also goes to head bridge to switch the reed relais of the bias trimmers according to FeCr/Fe switch in position "Fe".

I see, you have same version of print 1500 than me.
There are different versions of the FeCr/Fe switch.
And different versions of schematics too...

What is your serial number?

Best regards
Juergen

[paul_ral]

Thank you Juergen!
My unit is no 04001. Today I search on internet and I found I have a wrong position on 2100 connector. That caused theblowing that 1.6A fuse and no 20V from 2100 power bord.
Wrong position

Correct position as follow

It is very easy to put that connector in the wrong way. After power on the red led lights off and the green one from START is lighting on.

It seems it will be in working condition, I have to wait for new belts from Germany.

Best regars,
Paul

---

Thank you Juergen!
My unit is no 04001. Today I search on internet and I found I have a wrong position on 2100 connector. That caused theblowing that 1.6A fuse and no 20V from 2100 power bord.
Wrong position

Correct position as follow

It is very easy to put that connector in the wrong way. After power on the red led lights off and the green one from START is lighting on.

It seems it will be in working condition, I have to wait for new belts from Germany.

Best regards,
Paul

[paul_ral]

Thank you Juergen!
My unit is no 04001. Today I search on internet and I found I have a wrong position on 2100 connector. That caused the blowing of 1.6A fuse and no 20V from 2100 power bord.
Wrong position

Correct position as follow

It is very easy to put that connector in the wrong way. After power on the red led lights off and the green one from START is lighting on.

It seems it will be in working condition, I have to wait for new belts from Germany.

Best regards,
Paul

[JumAC]

Should be the green light of STOP...
I always make digicam photos before unplugging something.
Fine, that it seems you got no further defect than the fuse.
Best regards
Juergen

[paul_ral]

Yes, this is the led for STOP indeed, my mistake. This was how this Uher come to me. All voltages are correct now, it needs new belts (are on the way), a power switch and vumeter as well. Maybe I will able to repair the vumeter, the magnets inside need to be glued.