History of Esky Electronics

September of 2021, we were asked by a local logging company to see if we could repair his shifter for his Komatsu grader. We worked as engineers and technicians for a company that made automotive grade electronics. When we tore apart the U-Gate shifter (1439 905 H92) and found the completely potted circuit board bad. We searched the internet for a whole new unit or a replacement circuit board but found none. The grader owner was in need. He had a good fully operating grader but couldn’t move it. After much deliberation, we figured that if we designed another circuit board from scratch, we could get the grader back in operation. We removed the potting off the board and reversed engineered. We read Komatsu Parts and Service News and Manuals along with pouring over the grader’s schematics. We also talked to the service people at the logging company and the local Komatsu dealership. The older shifters used a rotary switch to control the various solenoids and relays. We settled on a hardware solution, without any computer or software involved. This hardware solution will output the electronically not mechanically the different states for each of the shift positions. We have experience in 24 volt off road systems and designed the power stage to exceed the specifications of the original U-Gate shifter. This solution will fit in the casing with the same form and function. The only difference is there is no diagnostic light. The unit has no computer so no diagnostics. We have P/N: REP 1439 905 running since July of 2022 with no issues. This grader is used weekly excluding the winter months. We have field tested other units also without any issues.

Printed Circuit Board P/N: REP 1439 905 features:

• Power 9 to 36 volts • Reverse Battery Protection to -36 volts • Overvoltage Protection – Unit will shut down if power is greater than 33 to 36 volts. • Transient Voltage Protection from chattering relays or solenoid kickback voltages. • Large heatsinking to keep the power semiconductors cool. • Monitors the shift position 4 times a second. • Capable of handling over twice the rated solenoid current. (> 6 amps) • No Computer. The controller uses hardware wired logic to properly operate the vehicles solenoids and relays. • Automotive Grade components. • -40°C to 95°C (-40°F to 200°F) Ambient Temperature Rating. • Handles high vibration environments. • Conformal Coating to protect the board from dust and moisture. • Drop-in replacement for the U Gate Shifter.

Esky Electronics Replacement board for Komatsu U-Gate Shifter (P/N 1439 905 H91 and 1429 905 H92)

Esky Electronics P/N: REP 1439 905 $1300 ea. USD Includes shipping within the continental United States Any orders outside of the continental United States please call. Send your complete U-Gate shifter and we will test to see if a new board is required. If your sent unit tests good, you will be charged a $250 USD fee which will include shipping within the continental United States. After your U-Gate shifter is repaired, it will be tested to verify its operation before shipment. Our tester will place each output pin under load and the proper sequence is verified for each position. We will buy any old Komatsu shifters.