TW 160HP / Feed roller not working

[Nicolas]

Hello, 

My son is a young arborist (21 years old) in south of France, I write this topic to find help to diagnose and fix an issue with his chipper.

The feeders rollers doesn't work, I have checked (with oscilloscope) the no stress unit, signal is present on pin SIG (1Khz @ low RPM and +/-3.8Khz @ full RPM), the OUT pin will go to ground when RPM is at +/- 3.3Khz (3300RPM).
Red light is on onto the no stress unit, i think there is no problem with the unit.

Relays are healthy also, tested with 12v power supply, and inverted between them.

SAFETY RELAY has 12v on pin 3 but  FWD SOL RELAY has no voltage on all pin.

Led onto hydraulic unit control is off (normally red light is present when it's ok).

Three diodes are good also.

 

I have checked belt tension it's ok --> 2mm deflection

 

Could you help me ?

 

Regards.

Edited May 8, 2020 by Nicolas

[Husqvarna King]

Hi, I'm not very good with machinery electrics but have run both older versions of the 160, the 125 and the entec 150. When I have had similar problems it has been the relay (car style one). One occasion it was the roller engagement switch.

Another thing on some of the older chippers is the throttle needs to be flat out to run the rollers. I had a bungee on the entec to stop it creeping back and the rollers stopping. It worked a treat.

Good luck and let us know how you get on ?

Edited May 8, 2020 by Husqvarna King

[Nicolas]

Thank you for your help, all the switchs are good, relays are swapped between them and tested one by one with external 12v power supply, coils are working and contacts are good.

 

12V missing on the FWD SOL RELAY, if I unplug the output wires from this relay (purple/white and black) and apply 12v power supply directly then the chipper is working but without no stress unit control security (understand the feeders rollers works even @ low RPM.

 

I will try to check cables with continuity test.

[Nicolas]

I have found a connector behind the chipper (near the fuel tank), this connector is connecting all the feeders rollers switchs and emergency switch with the relay on the front of the chipper, lot of oxidation, after little cleaning the 12v is present on FWD SOL RELAY if I push the red bar.

 

The chipper work, i need to clean the connector very well.

[Husqvarna King]

3 minutes ago, Nicolas said:

I have found a connector behind the chipper (near the fuel tank), this connector is connecting all the feeders rollers switchs and emergency switch with the relay on the front of the chipper, lot of oxidation, after little cleaning the 12v is present on FWD SOL RELAY if I push the red bar.

 

The chipper work, i need to clean the connector very well.

Well done. ?

[openspaceman]

14 minutes ago, Nicolas said:

I have found a connector behind the chipper (near the fuel tank), this connector is connecting all the feeders rollers switchs and emergency switch with the relay on the front of the chipper, lot of oxidation, after little cleaning the 12v is present on FWD SOL RELAY if I push the red bar.

 

The chipper work, i need to clean the connector very well.

Very good fault finding and analysis, well done your son will be proud.