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A. Williamson

Active Member
Joined
May 29, 2021
Messages
27
Location
USA
Hi all,
I'm working on a snorkel tb60. I believe it is a 2001 but I can get an exact date/serial number if needed. I have a service manual which has been pretty useful. It has multiple issues. I got called out because it had no swing function and intermittent/unresponsive controls on platform. It had been sitting for 2 years and when I opened the swing gearbox I found that there was no oil and it was frozen with rust. I sandblasted the internals and rebuilt it. Snorkel wanted $115 for the friction discs in the swing brake (qty 7) so I opted to use the old ones. If anyone knows a more reasonably priced source for the friction discs that would be greatly appreciated.

I spent some time today to colorize the electrical schematic from the service manual. It was a bit hard to follow before I did this and I found it helps me stay focused. I will attach my version. Use a pdf viewer that lets you turn on/off layers. I found mobile apps can't do this.

My question today is in regards to the "Proportional Bypass Coil" which is on the bottom right side of the electrical diagram. It is fed through one of two rheostats. Does this coil shift a valve in the "Control Valve Package"? I see there is one 4way 2position valve there that looks like it has pressure compensated flow control to tank in the energized position. The coils on the hydraulics diagram are not cross-referenced to the electrical diagrams. My best guess is that this valve is there to limit flow to the non-proportional DCVs that control the hydraulic functions other than drive/lift/swing. If you can give me more insight i'd appreciate it. I will try to get a pic of the hydraulic circuit diagram to add to the post for clarity.

Thanks
 

Attachments

  • Snorkel TB60 Electrical Diagram Colorized.pdf
    5.5 MB · Views: 18

A. Williamson

Active Member
Joined
May 29, 2021
Messages
27
Location
USA
Here is the hydraulic circuit schematic. The "Control Valve Package" i'm referring to is basically in the center of the page. The valve I'm guessing is controlled by the "proportional bypass coil" is the one on the right with the variable solenoid on bottom.
 

Attachments

  • 20210620_213422.jpg
    20210620_213422.jpg
    2.5 MB · Views: 8

A. Williamson

Active Member
Joined
May 29, 2021
Messages
27
Location
USA
Well, I finished the repair today. Sense line dump valve signal wire from platform had broken in its insulation. I used a spare wire in the same cable to fix it. Took me a while to figure it out - probably longer than it should have. Not used to these machines yet. And I didn't have my good meter with me.

The rheostat in the platform controls is not great and the swing brake seems like it needs new friction discs because it is real jerky when you stop swinging. It bounces side to side which is unnerving up in the air.
 
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