Effect of no FU1 fuse?

[flainn]

Hi all,

One of the things missing from my MEP-802A is the FU1 fuse and holder. I've been able to find from other threads that a 30 amp ceramic fast-blow fuse should go in there; I'll work on finding a fuse and end cap.

I'm wondering, does the FU1 fuse serve any purpose other than to let the alternator charge the batteries?

This weekend I hooked up two new, good 12v batteries. I can get the engine to crank fine with the dead crank switch, but all I get with the master switch is that the fuel and coolant temperature gauges both go hard-left (zero) when I turn the switch. However, nothing else on the control panel works -- not even the panel lights -- and I can't crank the engine from the master switch.

Is the lack of an FU1 fuse causing this? Or is it likely something else?

 

[kloppk]

Correct. FU1 is on the output of the alternator. Without it the generator should work just fine except charge the batteries.

Are you sure the panel lights have good bulbs in them?

How you downloaded the TM's for your 802?

 

[Guyfang]

What kind of S1 is in your set?
How many hours on the set?
Have you read the troubleshooting guide in the TM's Kloppk mentioned?
Do you have and can use a multimeter?

 

[flainn]

Correct. FU1 is on the output of the alternator. Without it the generator should work just fine except charge the batteries.

Are you sure the panel lights have good bulbs in them?

How you downloaded the TM's for your 802?

Ok.

I looked at two of the bulbs (wasn't able to unscrew the third) and the filaments looked good, but that's the extent of how sure I am.

I've got the 802A operations manual and will work through the no-crank troubleshooting procedure.

 

[flainn]

What kind of S1 is in your set?
How many hours on the set?
Have you read the troubleshooting guide in the TM's Kloppk mentioned?
Do you have and can use a multimeter?

My S1 is a five-position switch: Preheat - Off - Prime & Run Aux Fuel - Prime & Run - Start.

919.2 hours. Letterkenny Army Depot did a Tier 2 RESET in 2008 at about 4 hours on the set, so it's seen some use since. Radiator hoses were in terrible shape and there was no coolant in the rad or the block, but I'm replacing the hoses.

Yup, I've both got and can use a VOM. I'll work through the troubleshooting procedure when the weather permits (i.e., wind not 50+ mph gusts...)

 

[Daybreak]

Howdy,
Before you possibly hurt something on your set. Read through this thread, and check out a bunch of the quick links.

MEP-802A MEP-803A Filters and Parts

The question about the S1 is which generation style you have?

MEP-8xx S1 and S6 switch variations

 

[flainn]

Thanks Daybreak.

Mine has the bakelite-style S1 switch, and it does have the quad fuse fix installed already.

 

[Guyfang]

Ok.

I looked at two of the bulbs (wasn't able to unscrew the third) and the filaments looked good, but that's the extent of how sure I am.

I've got the 802A operations manual and will work through the no-crank troubleshooting procedure.

Stop. If the panel light do not work, you do not have 24VDC in the control panel. If the light bulbs are good, and will not turn on, find the reason why. Your starting problem will probably fixed also. Did you check S17?

 

[flainn]

Stop. If the panel light do not work, you do not have 24VDC in the control panel. If the light bulbs are good, and will not turn on, find the reason why. Your starting problem will probably fixed also. Did you check S17?

I believe S17 is the emergency stop switch. I did check that. If it's pulled out, I get the fuel and temperature gauges zeroing themselves when I turn the master switch to "prime & run", but nothing else happens. If S17 is pushed in (as expected), I get nothing.

It seems I've got 24v to two gauges, but nothing else.

 

[Guyfang]

You need to read the Operators TM. The S17 is in the ON position, pulled out. Pushed in, it kills the 24 VDC in the control panel. Any emergency switch is designed to be off when you slap it.

 

[Guyfang]

Are you standing near the set? If so, lets work this through.

 

[flainn]

You need to read the Operators TM. The S17 is in the ON position, pulled out. Pushed in, it kills the 24 VDC in the control panel. Any emergency switch is designed to be off when you slap it.

Yes, I know. I'm well aware of how one of those switches works.

 

[flainn]

Are you standing near the set? If so, lets work this through.

No. I'm at work today, 30 miles away. As I said above, when the weather doesn't suck (it does today), I will work through the troubleshooting procedure.

 

[flainn]

I'm not completely clueless when it comes to engines and electrical. I'm a ham radio operator, and I've owned a dozen diesel vehicles, all of which I've maintained. Also, I'm an IT guy. So please go ahead and stop assuming that I'm clueless, would you? Thanks.

I don't need to read through a 200-page manual to know how an emergency stop switch works. Also, I *have* been reading through the manual -- hence why I referenced its troubleshooting procedure. So please stop telling me I need to read it; I *am* reading it.

I appreciate the help; I don't appreciate condescension.

 

[Daybreak]

Howdy,
STOP
double check all connection are good

* if your a IT guy. Post in the correct areas and read through the forums.

OK, I see your remarks back in the above post.

Good luck to you. ~~bye

 

[flainn]

I already told you I have the quad winding fuse mod. So you're claiming that if the stator is blown, the engine won't even crank from SW1? That makes no sense from the wiring diagram. Nor does it square with the fact that the engine cranks just fine from the dead crank switch.

I'm trying to keep my cool, but honestly I'm getting kind of fed up with the treatment I'm receiving here. Am I missing something, Daybreak? I was the one who started this thread.

 

[Daybreak]

Howdy,
Slow down.
There are some nuances regarding the MEP-802a, and MEP-803a starting procedures. The quad winding fuse is important. Trying to start to long can still damage stuff. This knowledge is being passed to you. You are getting information and tips which is what your asking for. A bunch of snide remarks certainly will not help.

good luck ~~ bye

 

[flainn]

Ok, you know what? I'll go it on my own. Enjoy yourselves.

 

[Guyfang]

I'm not completely clueless when it comes to engines and electrical. I'm a ham radio operator, and I've owned a dozen diesel vehicles, all of which I've maintained. Also, I'm an IT guy. So please go ahead and stop assuming that I'm clueless, would you? Thanks.

I don't need to read through a 200-page manual to know how an emergency stop switch works. Also, I *have* been reading through the manual -- hence why I referenced its troubleshooting procedure. So please stop telling me I need to read it; I *am* reading it.

I appreciate the help; I don't appreciate condescension.

Apologies to you sir.

But then you haven't shared all this info with us. And most folks who are here for help, are clueless.

Start at the S1. See if you have VDC at S1-3 and S1-7 when in the start position. You should also have VDC at S1-2,4,6 and 8, (they are common) when the S1 is in any position other then OFF. do you have VDC at the A2 fault indicator. Simply use the PTT switch on the A2. See if you have VDC at the DS1, DS2 and DS3. They should get VDC from S1-6, via S2.

This type fault reminds me of the canon plugs on the bottom of the set being loose and or pins being arced off due to being loose. S10 will work, but nothing else.

 

[jamawieb]

FU1 is only for the alternator recharging, does not effect starting. I usually get a fuse used in microwaves (glass type can't remember amperage). These units are known to have faulty master switches, that is what Guyfang is wanting you to check.
DC power comes into MT4 Stint, then to the CB1 breaker above FU1 and then through CR2 Diode mounted towards the bottom of the burden resistors, then to master switch. I would check power at the CB1 breaker first and then move to the master switch.
I will tell you that everyone that posted on here is just trying to help, you don't need to be on the offensive. No one is assuming your an idiot like you think. They are trying to think of the simpliest things first and referencing the TM because it may bring light to the problem that we can't figure out.