MEP-803a: where did my press to test lights go?

[m32825]

New to me MEP-803a, trying to get it to start and run...

While working through the starting procedure in the operator's manual my press to test lights worked. After a couple tries the engine started and ran while I held it in start, but when I let go it stopped. Would not start on retry. Backed up and found that I am no longer getting press to test lights. CB1 is in and F1 is good, dead crank is normal, E-stop is out, panel lighting will come on, engine turns over. Suggestions? Thanks!

-- Carl

 

[DieselAddict]

I would recommend putting the dead crank switch in "OFF" and exercising your start switch a few times. Wet it down with contact cleaner if you have it. Do the same for the e-stop switch.

Be sure to hold the unit in "START" until you see oil pressure on the gauge. Otherwise it will die when you let it go.

If exercising the switch doesn't work it will be time to break out a voltage meter and take a few readings.

 

[Guyfang]

Which press to test lights? The A2, fault indicator? The DS& and DS7? Big difference.

 

[m32825]

Which press to test lights? The A2, fault indicator? The DS& and DS7? Big difference.

None of the press to test lights are doing anything. I saw them all working earlier today.

-- Carl

 

[m32825]

I would recommend putting the dead crank switch in "OFF" and exercising your start switch a few times. Wet it down with contact cleaner if you have it. Do the same for the e-stop switch.

Be sure to hold the unit in "START" until you see oil pressure on the gauge. Otherwise it will die when you let it go.

If exercising the switch doesn't work it will be time to break out a voltage meter and take a few readings.

I appreciate the suggestions. I exercised it all, no change though.

Trying to make sense of the schematic now. I'm getting power past the E-stop switch because I can see the panel lights come on when the switch is out. Back to the schematic...

-- Carl

 

[Guyfang]

All these problems are related. So try and see if you have power to the S1 start switch.

See if you have voltage, (24 volt DC) to pins 2-4-6-8, (these are the common connections) and at pin 3, on the S1, with S1 in the PRIME & RUN position.

If you do, see if you have voltage at pins 3 & 7 of the S1, when you hold the S1 in the start position.

 

[m32825]

All these problems are related. So try and see if you have power to the S1 start switch.

See if you have voltage, (24 volt DC) to pins 2-4-6-8, (these are the common connections) and at pin 3, on the S1, with S1 in the PRIME & RUN position.

If you do, see if you have voltage at pins 3 & 7 of the S1, when you hold the S1 in the start position.

Rain has shut me down for today, will try this tomorrow and let you know what I find.

Update: ignoring the lack of press to test lighting, the engine does start and run for as long as I hold it in start, then shuts down when I release back to prime & run. Not sure what that means, just passing it along for consideration.

-- Carl

 

[Guyfang]

Do you know the difference between the three different S1 switches? If not, take a picture of the S1. Best is from inside the control cube.

 

[m32825]

Woohoo, it lives!

You guys put me exactly on the right path with looking at S1. I measured an open circuit between pin 2 and the other common pins, worked the switch back and forth a while and got continuity. Sure helps to have feedback from the multimeter to know when you're "done"... or at least making progress. Then Looked at pin 3, got continuity in start, but not in prime and run. Worked it back and forth some more and got continuity. Hooked everything back up and all the press to test lights worked. Unit started and ran with no problem.

Found a loose bolt on the fuel solenoid actuator slide. Got the frequency adjust mechanism moving. Voltage is steady, but frequency wanders a few Hz on either side of 60. Seems to be solid if I set it a few Hz high or low though. I need to check it with my Kill A Watt, can anyone tell me where I put it?

I'm excited. This thing is a beast, it's so cool to hear it running!

-- Carl

 

[m32825]

Do you know the difference between the three different S1 switches? If not, take a picture of the S1. Best is from inside the control cube.

I do now, thanks for the head's up. Pictures of mine below.

-- Carl

 

[m32825]

>I need to check it with my Kill A Watt, can anyone tell me where I put it?

Just for future reference, the answer was "ask your teenager".

The voltage and frequency look pretty stable on the Kill A Watt meter, but the frequency meter on the panel jumps around. Working on a way to do some load testing next.

-- Carl

 

[Guyfang]

Your S1 is a type 3. Normally a VERY good switch. But looking at the pictures, it appears that the switch is very corroded. If you feel froggy. Take it apart and clean it. But you better feel REAL froggy. I wouldn't. If you continue to have problems, A new swith is in order.

The jumpy frequently meter sounds like a loose wire, or bad contact. Measure the input of the freq transducer. Then the output. This is the one time a analog meter would be better. You can see if your voltages are steady. Digital meters suck for this kind of measurement. The meter itself can also be the problem.