Hello folks: I have a Caterpillar 312 6GK00392 that controller board seems to be dead. Can not find schematics on it and it says that it has Mitsubishi part numbers. Don't find listing on 312 schematics for AC/heater unit are they separate? Does anyone know what the voltage on these units are? Since everything is 24 volt I assume they are that but the controller unit says it is 12 volts. Had a couple of blown capacitors on controller board but fuses were good. Does anyone know what voltage the actuator doors run? Blower motor runs when connected directly to 24 volts is just fine. Thanks in advance.
S'funny. The heater & A/C system appear on the schematic I have. The same one (SENR6129) that I posted when you asked before. Look on Grid Ref E-6 on page 2. Also take a look at the Table in Grid A-7 on the same page. It shows the reference colours for the heater/airconditioner circuit. The machine is 24V so therefore all the attachments should be 24V as well, unless they are things like comms radios and are powered via a 24/12V converter. Has someone maybe installed a wrong part in the past.? The bad news from your pint of view is that the 4I-0470 A/C unit controller has been discontinued by Cat, unless you can find an aftermarket replcement.
Dear Nige: The schematics that you sent were invaluable to me. I must not be able to read them correctly but I want the schematic to the 5I3583 control module which is stamped made by Mitsubishi. Also the control panel is also stamped Mitsubishi but says 12 volts on it and unless they cut the voltage in the control module that seems odd. It is stamped 12 volts on it making me wonder if it was replaced in the past. This is a Grey market machine and my Cat dealer can not make any of the Mitsubishi numbers cross to anything. Will look where you told me on schematics again I easily could have missed them. There is no shame in getting older, it is just terribly inconvenient. Thanks!
Dear Nige: I failed to look at RENR 1039-01 it is very helpful. It is good people like you that provide invaluable aid! I will just rebuild the circuit boards if I can not find a new board or a working used one. Thanks
Yeah tell me about it. That old age thing is a pain in the proverbial........ The Schematic does NOT show any detail regarding the control unit. Just shows a box with various colours/numbers of wires going into it, so maybe it doesn't show what you are looking for. Gives the impression that the unit is not serviceable, or not designed to be serviceable anyway. But we all know where there's a will...... The problem with your grey market machine is that all the cross-references for it are all "thumb sucks" because it is listed NOWHERE in any Cat x-ref documentation. It is the ONLY model in the whole 300A/B/C/D-series excavator line that isn't crossed to a non-Japanese machine and I have no explanation as to why that would be the case. Maybe it is different to all the other 312 models on the market. My comments regarding 12v/24v are generalizing. Normally a manufacturer would run everything on machine system voltage for simplicity, but with these particular machines who knows what Mitsubishi did..? It doesn't help never having laid hands on one.
If you never had to work on a grey market count your blessings! . Having said that it is a good little machine and has been relative problem free. Even with 4000 hours on it the wipers and everything else still works. Just the lack of heat and air is a problem. Thought the price was right and got it for less than 16k, so a little repair problems go with it. My brother is an electronics technician so rebuilding the boards is possible for me. Thanks for all of your aid!