Mep-802a no start.

[Lawman21]

Howdy,

Take some pictures of the back side of your S-1 switch. Showing what wires are connected.

 

[Lawman21]

 

[Guyfang]

Like I said before. Version 1 of the S1 switch.

The side of the switch you can see in the picture is the "common" side. The common side is: pins 2,4,6,8 all show the same value. In this case, 24Volts, DC.

With the switch in any position other than OFF, these four screws should have 24 volts DC. Start with pin 2. Pin 2 is directly connected to CB1, the DC Control Circuit Breaker. If you don't have voltage on pin 2, the S1 is good. Look at CB1 and S17.

But, if pin 2 is hot, then measure pins 4,6,8. They should all show 24 volts. If one or more pins do not show 24 VDC, the S1 switch is bad. If all four of the pins are hot, do the next step.

Hold the S1 in the start position. Mesure pins 3 and 7. They should have 24 volts DC. If they do NOT read 24 volts DC, the S1 is bad.

 

[Lawman21]

Like I said before. Version 1 of the S1 switch.

The side of the switch you can see in the picture is the "common" side. The common side is: pins 2,4,6,8 all show the same value. In this case, 24Volts, DC.

With the switch in any position other than OFF, these four screws should have 24 volts DC. Start with pin 2. Pin 2 is directly connected to CB1, the DC Control Circuit Breaker. If you don't have voltage on pin 2, the S1 is good. Look at CB1 and S17.

But, if pin 2 is hot, then measure pins 4,6,8. They should all show 24 volts. If one or more pins do not show 24 VDC, the S1 switch is bad. If all four of the pins are hot, do the next step.

Hold the S1 in the start position. Mesure pins 3 and 7. They should have 24 volts DC. If they do NOT read 24 volts DC, the S1 is bad.

 

[Guyfang]

I would say to you, that gen set #2 has a bad start switch. Lets work on one at a time. And gen set #2 is a good one to start with. With those readings, its clear, that you need a new switch, or its wired wrong. In an earlier post I gave you a snapshot of the switch, and wich wires go to which pin. And it showed the correct direction to install the diode. The correct way to check the diode is listed in the TM, if you do not know how. If you have checked and double checked that, then it can only be the switch. A good way to prove it is thus. Put the S1 in the run position. Take a wire, ( I use a very long flexible wire. with multimeter probes on both sides) and touch one side on common, (pins 2,4,6 and and then touch the other on pin 7. The engine should turn over. Try it.

 

[Lawman21]

I would say to you, that gen set #2 has a bad start switch. Lets work on one at a time. And gen set #2 is a good one to start with. With those readings, its clear, that you need a new switch, or its wired wrong. In an earlier post I gave you a snapshot of the switch, and wich wires go to which pin. And it showed the correct direction to install the diode. The correct way to check the diode is listed in the TM, if you do not know how. If you have checked and double checked that, then it can only be the switch. A good way to prove it is thus. Put the S1 in the run position. Take a wire, ( I use a very long flexible wire. with multimeter probes on both sides) and touch one side on common, (pins 2,4,6 and and then touch the other on pin 7. The engine should turn over. Try it.

Thank you so much..

Where can i purchase switches ?

 

[Guyfang]

There are three different types. The first two types are not real reliable. You can find some of them in the big auction site, or several sites that offer parts for army equipment. Most offer S1's at a very high price. You can take the part numbers and NSNs and plug them into your browser. Lots of places come up. Prices are high. I suppose I would go to the type 3 manufacturer, and buy there. Or look for a type 3 in the internet. Simply because I know I would never have another problem again in my life. Even if I do hit 100 years. There are several threads that provide that info. You got to look around. Find one your wallet can get along with. Its la la time on your side of the big pond. Perhaps in a few hours, some of the other guys who have bought switches will jump in here and add another two or three cents.

 

[Lawman21]

There are three different types. The first two types are not real reliable. You can find some of them in the big auction site, or several sites that offer parts for army equipment. Most offer S1's at a very high price. You can take the part numbers and NSNs and plug them into your browser. Lots of places come up. Prices are high. I suppose I would go to the type 3 manufacturer, and buy there. Or look for a type 3 in the internet. Simply because I know I would never have another problem again in my life. Even if I do hit 100 years. There are several threads that provide that info. You got to look around. Find one your wallet can get along with. Its la la time on your side of the big pond. Perhaps in a few hours, some of the other guys who have bought switches will jump in here and add another two or three cents.

How is the part listed. Ive googled it and no matched appear.

 

[Guyfang]

Originally Posted by dav5
Guyfang I think I have read all your generator posts. With your help plus other contributors I am now fairly comfortable with the TM's. I now even know what the cage code is. The one thing I am still having trouble with is "usable on code". Specifically I am buying spare parts for my MEP 803A when I see them for a good price. I want to buy a master switch. It is advertised as a switch for an 804a NSN 5930-01-531-2975. PN 31904QT. I looked up the NSN for both the 803A and the 804A in your TM's and got the same # 5930-01-368-5160 which is obviously different. The photo looks identical to the 803a switch. There didn't seem to be any info in the usable on code section. Any advice. Thanks again. Ted



The NSN 5930-01-368-5160 is for the mark one switch. It works, but is not reliable, over long time periods. Its plastic, and can break.
The NSN 5930-01-498-9903 is, I think, for the mark two switch. Same problems as the mark one.
The NSN 5930-01-531-2976 is for the mark three switch. Last a lifetime switch.
The NSN 5930-01-531-2975. Someone needs to show me a manual or proof that it goes in a 803A or any other gen set I know. I looked in all the manuals, and cant find it. I cant say, 100% that it wont fit. But sure cant find any reference that it does.​

If you open your parts manual and look at the exploded picture of the control panel, you will find that item 22 is the switch. The part number is: 88-21160. The NSN is the highlighted NSN above. The information was posted in another thread last month. If you plug in the NSN into your browser, there are any number of possibilities. Cost is variable. But I saw one place that sold them for $245.00 and another for a little less. You can also try the other two numbers, and maybe find it cheaper. The quality is not as good, but that's on you.

 

[lonesouth]

I got one of these to work for mine. You will need to add a momentary switch for the pre-heat function.

ebay: search for NSN5930014989903

Be aware that this also has a plastic stalk and is prone to break just like the v1 and v2 original switches listed above ^^^

 

[Daybreak]

Howdy,

MEP-8xx S1 and S6 switch variations

 

[Lawman21]

I would say to you, that gen set #2 has a bad start switch. Lets work on one at a time. And gen set #2 is a good one to start with. With those readings, its clear, that you need a new switch, or its wired wrong. In an earlier post I gave you a snapshot of the switch, and wich wires go to which pin. And it showed the correct direction to install the diode. The correct way to check the diode is listed in the TM, if you do not know how. If you have checked and double checked that, then it can only be the switch. A good way to prove it is thus. Put the S1 in the run position. Take a wire, ( I use a very long flexible wire. with multimeter probes on both sides) and touch one side on common, (pins 2,4,6 and and then touch the other on pin 7. The engine should turn over. Try it.

Tried the wire trick..no start. It sparks and the 3rd relay from the left clicks. Tried 2 4 6..with wire on #7 still no start. Trying find switches that dont cost 300 a piece

 

[Guyfang]

The S1 in the first gen set appears to function. Just so you have something to do, take it out, and put it in Gen 2. Do not, trust how the wires have been attached to the switch. LOOK at each wire and check the wire number against the wire diagram. THEN attach them. Make sure the diode is attached in the right direction. Then try gen set 2.

You could have several problems in your set. So you need to go one step at a time. Take the time to look at the relays. There are numbers next to the relays. Instead of saying "the 3rd relay from the left clicks", tell us what relay clicks. Also make sure that you check that what you think is a relay, S14, is not a relay. Its a switch. Looks just like a relay, but isn't. Make sure it S14.

 

[Lawman21]

The S1 in the first gen set appears to function. Just so you have something to do, take it out, and put it in Gen 2. Do not, trust how the wires have been attached to the switch. LOOK at each wire and check the wire number against the wire diagram. THEN attach them. Make sure the diode is attached in the right direction. Then try gen set 2.

You could have several problems in your set. So you need to go one step at a time. Take the time to look at the relays. There are numbers next to the relays. Instead of saying "the 3rd relay from the left clicks", tell us what relay clicks. Also make sure that you check that what you think is a relay, S14, is not a relay. Its a switch. Looks just like a relay, but isn't. Make sure it S14.

Gen set 1 originally ran..then just stopped. It was after applying a load and the circuit tripped. The gen didnt start after that. Ill look at the relay. Thank you.for all.your help i appreciate it.