I've been trying to figure out what's happening with the quick tach on a t190. It will close, but not open. The switch is good. Does anybody know where the solenoids are located or what they look like. I found two solenoids under the seat, but when unplugged the engine still loads when I hit the tach button. Can someone shed some light on this??
power bobtach valve is mounted on the backside ( between the eng & pumps) of the hyd pump. 2 coils mounted piggyback on the left side of the valve. the 2 solenoids you found are probably the aux coils. :drinkup
And an absolute PITA to get to and work on. Could simply be wiring problem, could be bad coil, could be spool stuck. If it's spool stuck, you might consider checking the case drain filters for both drive motors for debris, fragments in the hyd oil will make the bobtach spool stick.
I found it shortly after I posted. The other guys in the shop told me the two that we were focusing on were the ones. But realized that when I pushed down on the switch with both of them disconnected the motor lugged. I got both of the right coils (this time) off and ohmed them out. both showed low resistance around 25. My meters finicky at best and usually reads around 18-20 when I zero it. spent a while trying to figure out what size the spool was and gave up for the day. Now apparently this machine has been to bobcat for this problem a few weeks ago, and they cleaned the spool out and the problem came back within a week. I'm going to check out the drive motors and probably change the hydro filter before I get the spool out and see where I stand. thanks for the advice!
Don't just change the hyd filter, remove the filter and drain it into a clean drain pan to look for metal in the oil. Once it's drained, pour some diesel fuel, mineral spirits, or naptha into filter, place your hand over end of filter and shake it. Drain the solvent into clean pan and check metal content. If you have a recurring problem with Bobtach spool sticking, be sure and check the case drain filters for the drive motors, they're underneath the cab. If one of them has a good bit of debris inside the case drain filter, good possibility that drive motor is headed south.
if the pwr bobtach spool has been cleand and the problem came back a week later, start by replacing the hyd filt, and case drain filters, dump the hyd tank. typically once the pwrbobtach spool starts sticking, it will never stop sticking, no matter what you do. replace the entire valve is usually the only solution :drinkup
I found out the hard way that you can't buy parts for the power bobtach valve body, you have to get the complete assembly. It's kinda of a pita to get out too. What i did was clean the case drain filters, replace the hydraulic filter, and get a new valve assembly, and just take the new spool and solenoids and put them in the old one. Works like a charm now. We'll see for how long. Side note, this t190 is killing me. Guys went to load it up for a job, leaking diesel. Right where that crankcase drain hose rests of the fuel tank, there's a nice little hole.... Not a good day ha ha.
Power bobtach valve problems eqaul drive motor problems.
My power Bobtach problems were followed by the hyd pump failing. The Bobtach valve is the first thing that oil goes through once it leaves the pump. Good luck, there is nothing involved with this that is easy to work on.