939 trucks and EMP

[Dmaxcc6spd]

Does anyone in the group have some information on how a 900 series truck would do if there were a serious EMP event? I haven't had a chance to crawl all over a truck and get up close for a detailed inspection of the various components. Any information would be greatly appreciated.

 

[PsycoBob]

ABS is the most vulnerable- PM magazine loudly emntions to let the engine stop completely before shutting off the battery switch, to protect the ABS from spikes.

From recent threads I've seen elsewhere, anything short of a nuke-emp wont bother vehicles. Solar EMP will only break big electrical systems like the national power grid but won't be strong enough to affect anything that doesn't have a miles-long wire attached to it. Given that even modern, computer-controlled cars have been tested to survive direct lightning strikes with minor malfunctions, I doubt the nearly-stone age m939 series trucks will have any issue.

If you really look at it, how many voltage-sensitive electronic components does a m939 have? ABS components, alternator, flasher module & push-button light switch? No computer-controlled common-rail fuel injection, transmission, headlights, etc. Might bork LED lights if hit with lightning.

 

[doghead]

I can't imagine driving a 900 series truck no ABS brakes after an apocalyptic nuclear war. You could skid right into all the zombies. Oh my.

 

[Warthog]

DH you know we don't talk about Zombies around here. Don't make me close this thread...

 

[Dmaxcc6spd]

ABS - Oh Well, bigger things to worry about. What about the control box? I saw that mentioned in another thread. Does anyone know what it does? Here are 2 links to discussion about the "box."

http://www.steelsoldiers.com/5-ton-up/11557-trouble-shooting-protective-control-box-5-ton-2.html

http://www.steelsoldiers.com/5-ton-up/68832-controle-box.html

 

[Ferroequinologist]

The exact operation and wiring diagraham are in the TM.

Or in other threads.

You can't start the truck without it unless you cut and splice wires.

 

[gimpyrobb]

Just stick to your CUCVs.

 

[EMD567]

The nuke blast would have to be so close for the EMP to affect the control box, that the truck would be unusable from the other stuff that a nuke blast produces. All the control box contains is two heavy duty relays. The EMP from a nuke affects computers the most, where it can induce electrical currents in the wrong places, burning out the IC chips.

 

[PsycoBob]

From looking around, the box houses the relays for the master power switch & starter relay. Diodes are used on the 809 series box to prevent contact arcing, much like the flasher module relay upgrade mod. I'm uncertain what the 939 series box does that the 809's box doesn't. 939 boxes work with 809 trucks, but not the other way around.

m809 box rebuild

 

[doghead]

Wouldn't you expect the sealed steel box to protect it's internals from an EMP?

 

[gimpyrobb]

Just rub those hillbilly curb feeler/ground strap thingys.

 

[PsycoBob]

Doghead, not with those wires coming out. A faraday cage only works if nobody pokes holes in it & runs emp-antennas (wires) out. To be honest, if I get nuked close enough to worry about my truck's electronics frying, I've got bigger problems.... like the fact that my tires on one side are on fire & I'm blind.

EMP is just about a non-issue with modern hardware, unless you expect to park in the beam-path of a phased-array radar (AEGIS cruiser) or have a 15kw+ radio tower land on your hood. It takes a LOT to induce enough voltage/current to nuke .mil/detroit spec diodes/chips. Most modern automotive grade IC's include some form of ESD protection that tends to help with brief spikes. Everyone's used to household computers with nice, touchy electronics. Go nail an old-school discrete-transistor device with a few carpet/wool-sock shocks. Odds are, it'll survive just fine. Now try doing that with an MP3 player's exposed circuit board.

Of course, a ham radio attached to a huge amp & a bumper-mounted antenna might induce enough current in the wiring to make the turn signals flash every time you transmit. Square-cubed law applies- park the transmitter on the truck, get a huge effect compared to a half-megaton nuke 20 miles away.



Gimpy, that's brilliant- use a set of small crane weights or wrecker-balls like 'truck nuts' off the pintle as a ground strap. Just the thing to reduce tailgaters.

 

[Dmaxcc6spd]

ABS - Oh Well, bigger things to worry about. What about the control box? I saw that mentioned in another thread. Does anyone know what it does? Here are 2 links to discussion about the "box."

http://www.steelsoldiers.com/5-ton-up/11557-trouble-shooting-protective-control-box-5-ton-2.html

http://www.steelsoldiers.com/5-ton-up/68832-controle-box.html