Need Electrical Schematic 753H non-Adv Hand Control

[Skidder Dave]

I have a 753H s/n 512726836. I purchased a real deal hard copy shop manual online which has been 99.9% great. But the included Electrical schematic for my serial number is for a machine having a AHC/PWM controls module for advanced proportional control of the front aux hyd outputs. My machine does not have the AHC/PWM control box at all. Front aux (grapple pinch bars) is currently not working and it would help debug immensely if I had the correct schematic. AUX OFF/ON button rings out as OK, RH handle toggle rings out OK (just off/on X2 not proportional). Solenoids both ring at 11ohms, OK per the (incorrect) schematic, but the manual “text” says 1-5ohms. Can anyone please send me a scan of the correct non-AHC electrical schematic? Thanx in advance for any help/advice/critique you can offer. SSF has saved my butt more than few times in the past! THANKS!

 

[flyerdan]

Have a look in the manual thread, there should be a 753 book in there that has wiring diagrams for various configs.

 

[Skidder Dave]

Have a look in the manual thread, there should be a 753 book in there that has wiring diagrams for various configs.

I tried the manual thread - actually several 753 manuals but none with the schematic I need. Thanks for trying! I’ll keep looking.

 

[Skidder Dave]

Have a look in the manual thread, there should be a 753 book in there that has wiring diagrams for various configs.

I figured out how Bobcat shafted me with this manual. The front of the manual says it covers my serial number. My machine is a 1996 753H. However in the back of the manual under “Service Manual Revisions”, Revision “753, 753H-1” dated 14 Nov 1997, the revision log (partial) says TAKE OUT Section 6 (Remove All Electrical Charts), and PUT IN Section 6 (All Electrical Charts). Sooo... even though my s/n is listed on the front of the manual, Bobcat removed the schematics applicable to my older m/c and updated the schematics to post-Nov of 1997. And apparently all of those later variations included AHC. Crap! I’m desperate - I even tried to talk to the only local Bobcat guru at a local rental shop, but he has moved on. If anyone can direct me to a 753H electrical schematic, non-advanced hand control, non-BOSS, please lemme know. Thanks!!!

 

[Skidder Dave]

OKAY... Still don’t have the right schematic but discovered today that my 753 DOES have a control module, just doesn’t look or mount anything like the one pictured in the Rev 1 manual. Mine is mounted on the left wall of the machine well, and it is about the size of a CD case but about 1 inch thick with 2 connectors. Priced a replacement at Bobcatparts.com at about $500. UGH! Next attempt I will take it out and hose all the contacts with cleaner, then try again to make it work. The AUX ON switch has continuity when pressed. I’ve got power at the AUX ON switch, but the signal is not making it (through the module) to the RH stick switch. The stick switch does ring continuity when actuated left and right okay so it is working. Fingers are crossed it’s a dirty contact...

 

[Skidder Dave]

***UPDATE*** - after chasing signal wires, installing a new AUX panel switch, installing a new AHC Controlller box ($ OUCH!), and accumulating over a year’s time here-and-there messing with this problem, it still did not work. Long story short, I finally discovered the black ground wire common to the AHC box and the solenoids was NOT grounded. I could not find the source of the break in the wire, so I jumpered locally to the brake solenoid black wire ground. It’s FIXED! I can use my grapple now - Woohoo! Hope this helps anybody having the same problem...

 

[Wayne440]

***UPDATE*** - after chasing signal wires, installing a new AUX panel switch, installing a new AHC Controlller box ($ OUCH!), and accumulating over a year’s time here-and-there messing with this problem, it still did not work. Long story short, I finally discovered the black ground wire common to the AHC box and the solenoids was NOT grounded. I could not find the source of the break in the wire, so I jumpered locally to the brake solenoid black wire ground. It’s FIXED! I can use my grapple now - Woohoo! Hope this helps anybody having the same problem...

Appreciate the follow up...it is sometimes easy to forget that grounds are of equal importance to "hot" leads.

 

[Tazza]

Appreciate the follow up...it is sometimes easy to forget that grounds are of equal importance to "hot" leads.

Grounding is a real issue in some machines, I don't get why they don't just have a few redundant ones in the harness to prevent issues like this.
I'm having issues that I feel is ground related, the issue can be finding the ground points to check that they are right.