M809 control box used in M939?

[LanceRobson]

Does anyone know if the control box for the NHC 250 in the M809 trucks is used in the NHC 250 powered M939s? I plan on selling my M813A1 and deuces and going to M939 series stuff and am trying to find out if the brand new control box I have in shelf stock can be used on a M939 or whether I should sell it with the other M809 specific parts.

Thanks

Lance

 

[jasonjc]

It depends on the part number. The M809 can use the M939 but not the other way, I've read on here.

 

[73m819]

whet he said, 900 on 809s, 809s NOT on 900s

 

[LanceRobson]

Thanks, I'm pretty sure mine is an M809 but now I'll have to find the PNs and check.

Lance

 

[diverman555]

The PN# for the 939 box is 11669304 it will work in the 809 truck, but the 809 truck box will not
work in the 939 truck.

 

[LanceRobson]

I have a PN 11664348, NSN 2920-00-472-1642 for the M809 so I guess it is going in the classifieds....

Thanks

Lance

 

[davey8943]

Call me a necromancer, but I think my question is best added to this thread, instead of creating a new one....

The Gov't had disconnected the batteries and starter switch in my new (to me) M934. I pulled a couple donor batteries from one of the deuces I have, and pulled the wiring diagram to figure out how to re-wire the starter switch.... I flip the switch(es) and... NUTHIN!!

In order to prove to myself the engine would run, I bypassed the Protective Control Box by jumping 12 volts to one leg of the accessory switch. Flipped a couple switches, and the engine roared to life. I let it run for only a few seconds before shutting it down and getting to work on the electrical system.

I traced my dead switch problems to the PCB, and found that it was bad per the TM check (supply 12 V to one pin and check continuity between two others). To find a replacement I contacted smittyjr355 (who had advertised as parting out a 923 in the classifieds). We agreed on a price, I sent a check, and his box was in my mailbox in no time flat!

Now on to my problem! The PCB that smitty sent (which came directly out of his M923 remember!) is stamped with 19207-11664348 (the number above referenced as usable only on 809 series trucks). The box from my truck is stamped with 19207-12450333 (above referenced as usable for 809 and 939 trucks).

I brought this up to Smittyjr355 and he responded quickly by offering to refund my money. I am in no way upset with him or how he handled the deal. He appears to be a stand up guy!

So my question is... should I try it in my truck? Is there any risk of damaging the new PCB (or anything on my truck) by hooking it up? I'd hate to needlessly smoke a PCB or something else, but don't want to waste more time and shipping money sending things through the mail again!

Thanks,
Dave

 

[davey8943]

No one wants to talk me out of it?

If someone doesn't help me wise up, I may try it and report back the results!

Thanks,
Dave

 

[indyradar]

Hey, same issue. Two questions. how did you bypass the PCB? and did the box from the 809 work. Im having the same issues.

 

[jdknech]

I am interested to know this as well?

 

[73m819]

A 809 PCB WILL NOT WORK in the 900 5ts, it has ONE more saftey circut (the auto. trans. NUTRAL start )

The ONLY REASON for the PCB is to keep a driver from trying to start the truck WHILE it is ALREADY RUNNING or in gear for the 900s (why it is called POTECTIVE CONTROL BOX), if the driver CANNOT here one of these trucks running from 25' away, let alone in the cab, has NO buisness in the cab.

So with the above said,There is NO reason that the PCB can not be done away with, It has TWO relays and a few other things, one is the saftey start relay with engine rotation (oil pressure senser) and nutral saftey switch (900s) driving it, the other relay is the MASTER POWER on/off that is controled by the dash battery/master switch.

I have operated a LOT of cranes that have the 855 (though ALL of the emgines are wired the same in the older cranes, now new ones are a wireing nightmare at times), these engines DO NOT have a PCB, just a master power relay controled by the on/off switch and a starter button. Some have Murphy guages for auto shutdowns or warning buzzers, but these are added saftey items

 

[sandcobra164]

I was about to throw out the same explanation Ron. And you're absolutely correct, if you can't hear a 5 ton running from 25 feet away, somethings wrong. At the last GA Rally, I heard your straight piped wrecker from quite a ways further than that. Those 855's are loud and it was my family's wake up call on Sunday morning. Worked out good though, I got the family up, tore down the tent and hauled tail back to Leesburg.

 

[Castle Bravo]

if the driver CANNOT here one of these trucks running from 25' away, let alone in the cab, has NO buisness in the cab.

While I do agree that they're loud, I have had to double check while starting many trucks parked in a row between buildings. When you've got half a dozen 5 tons started already, you can no longer tell which sounds are coming from which truck.