MEP-004A, No output

[peapvp]

You need to test on the Terminal, not the disconnected F1 and F2 wires!

 

[KLChurch]

Wow my mistake.
Also that can be good news.
Will set the mm again
Kris

 

[KLChurch]

Put the mm on the terminal not the wires where F1 and F2 are disconnected.
Got 24vdc in the start mode.
Kris

 

[peapvp]

Put the mm on the terminal not the wires where F1 and F2 are disconnected.
Got 24vdc in the start mode.
Kris

Good, now on to the next test

 

[KLChurch]

Tested H1 and H4 separately to ground with MM set at 250 VAC max.
Had gen running in run mode after starting.
No volts on either H1 nor H4 on the transformer.
Also no volts on volt meter in control panel.
Kris

 

[peapvp]

Tested H1 and H4 separately to ground with MM set at 250 VAC max.
Had gen running in run mode after starting.
No volts on either H1 nor H4 on the transformer.
Also no volts on volt meter in control panel.
Kris

No, One lead of mm goes on H1 the other lead of MM goes to H4

250VAC should be fine

 

[KLChurch]

OK that is good news again. Hopefully
I am a very bad elec technician.
Kris

 

[KLChurch]

Tested between H1 and H4 and still no volts. But as long as I hold the start in its mode I get 100 volts on the control panel and the hz jumped higher than before. In run no volts or HZ on the control panel.
Kris

 

[peapvp]

Tested between H1 and H4 and still no volts. But as long as I hold the start in its mode I get 100 volts on the control panel and the hz jumped higher than before. In run no volts or HZ on the control panel.
Kris

Ok, now did you change the Voltage Regulator Board with the one you bought on ebay? If so, this means that the parts (diodes / scr's) mounted on the heat sink next to Transformer T2 are gone - at this point you may want to consider sending the entire A11 unit to me for repair. I suspect that the 2 or 4 smaller chassis mounted caps are gone too.


If you have not swapped the Voltage Regulator Boards then you may want to make a decision to either change them yourself and re test this with meter on H1 and H4 or sent everything to me for repair.



When you hold the Switch in Start Position then 24 Volt are applied to F1 and F2 for field flashing - we tested this yesterday and this test checked out OK - hence you are seeing 100V on your gauge.


This flashing will apply the 100V to H1 and H4 as well but because the circuitry on the secondary side (Capacitors, SCR's / Diodes and Voltage Regulator Board ) are not working properly which is causing a no output voltage when you release the Start Switch to Run Mode


We know that the output reconnection board was wired correctly (No Modification).


This indicates that the cause for failure were the two capacitors with the Diode's/SCR's mounted on the heat sink - this circuit connects to the secondary side of the Transformer T2 and the entire circuit starts to oscillate when either one of the smaller caps or the Diode/Scr's are failing this in again results in an over current of the unprotected Transformer T2 which then blows up

 

[KLChurch]

Peter,
I will package up the A11 and new VR, then send them to you via UPS.
Kris

 

[KLChurch]

It may take a week or two before I can do another test.
Kris

 

[peapvp]

It may take a week or two before I can do another test.
Kris

which test would that be?

 

[peapvp]

Kris,

Do you want me to document this overhaul / repair / calibration of your A11 and post a more in-depth analysis of all the aging / defective parts which need to be replaced sooner then later here on Steel Soldiers with Video and Pictures?

After all, these Units are older than Methuselah by electronic components standards and anyone who believes that a A11 is going to work like a brand new Unit by just simply replacing a burnt Transformer needs to seriously have their head examined.

 

[KLChurch]

Yes Peter
I think the people that read this post should know the potential of the damage that can happen to these units and maybe help them evaluate their own machines.
So far I believe we have gone through a lot of troubleshooting and testing.
It has been a mission for me.
The next test will be when I get the A11 back.
Kris

 

[peapvp]

Yes Peter
I think the people that read this post should know the potential of the damage that can happen to these units and maybe help them evaluate their own machines.
So far I believe we have gone through a lot of troubleshooting and testing.
It has been a mission for me.
The next test will be when I get the A11 back.
Kris

Thanks Kris, will do - when you get your A11 back everything should fall into place. We will have a fully restored to spec A11 to work with - it maybe a good time now to replace the cooked, but still ohming correct to 1.5K Resistor on the other A5 board while I am getting A11 done and mean while you can also check out the other circuit boards throughout your 004A unit visually for signs of any damage or loose components.

 

[KLChurch]

OK
Their is another Resister next to the cooked R3 on A5, that seen heat also.
Where would I get those Resisters?
Good plan while I wait.
Kris

 

[peapvp]

Kris,

This would be also a good time to get intimately acquainted with the Parts Manual of your Genset, the -24P

TM-9-6115-464-24P

Any MEP Owner should take the time to learn to love this Manual as it is your friend and your companion

If you don't know the Item your looking for by name of Abbreviation (which is usually printed next to the part etc on the chassis) then skip the index and start to simply scroll through the manual until you find the explosion drawing of the compartment you are working in or have a trouble some part located.

After each explosion drawings is a list of all parts in that particular area listed by number as indicated in the explosion drawings

Sub parts, like circuit boards are usually on the following pages each with its own explosion drawing and then the parts list

Locate the A5 assembly by first finding the general area A5 is located - A5 with all its components is then listed afterwards

When you find the number in the explosion drawing of the component then go to the parts list and look up the Part # which could be listed as Manuafacturer Part Number or NSN National Stock Number

then google the part # / nsn to find out of what that part actually is - the NSN's are very detailed with Type of Resistor / Capacitor, Voltage / Watt Ratings beside the actual value of the component

Then you can go to Mouser.com or Digikey.com and search for a similar part in their searchable databases

If you can't find the part then post all relevant information from your goolge search here - this will make it easier to help find a cross reference

Please do not expect us to find every single part / nsn number in the parts manual for you - this is beyond the scope of this forum

"Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime"

OK
Their is another Resister next to the cooked R3 on A5, that seen heat also.
Where would I get those Resisters?
Good plan while I wait.
Kris

 

[peapvp]

WBParts has a great searchable Database for NSN and Part Numbers:

WBParts

 

[Guyfang]

Kris,

This would be also a good time to get intimately acquainted with the Parts Manual of your Genset, the -24P

TM-9-6115-464-24P

Any MEP Owner should take the time to learn to love this Manual as it is your friend and your companion

If you don't know the Item your looking for by name of Abbreviation (which is usually printed next to the part etc on the chassis) then skip the index and start to simply scroll through the manual until you find the explosion drawing of the compartment you are working in or have a trouble some part located.

After each explosion drawings is a list of all parts in that particular area listed by number as indicated in the explosion drawings

Sub parts, like circuit boards are usually on the following pages each with its own explosion drawing and then the parts list

Locate the A5 assembly by first finding the general area A5 is located - A5 with all its components is then listed afterwards

When you find the number in the explosion drawing of the component then go to the parts list and look up the Part # which could be listed as Manuafacturer Part Number or NSN National Stock Number

then google the part # / nsn to find out of what that part actually is - the NSN's are very detailed with Type of Resistor / Capacitor, Voltage / Watt Ratings beside the actual value of the component

Then you can go to Mouser.com or Digikey.com and search for a similar part in their searchable databases

If you can't find the part then post all relevant information from your goolge search here - this will make it easier to help find a cross reference

Please do not expect us to find every single part / nsn number in the parts manual for you - this is beyond the scope of this forum

"Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime"

I am going to jump in here.

The -24P for the 15 & 30 KW are often wrong, incomplete or contain errors. And here is one place. The 15 KW -24P has errors, concerning the A5 card. When you go to the exploded picture, you are not going to find the Item numbers. Its a fine picture, shows the resisters, but no Item number. So, what you gonna do? You go to the 30 KW -24P, and there are Item numbers next to the parts. As I have said several times, the majority of the parts are interchangeable between the 15 & 30 KW.

BUT, not all.

Now, another field to explain. UOC. Usable On Code. Just to remind you all, if anything is listed in this column, bells and whistles should go off in your head. Yo have to pay attention, or you will order the wrong part. As it so happens, the Sp/relay box is a part that can be used in all three versions of the 15KW, so no problem. But you have to LOOK.

And I agree. This is a good way to learn how to really USE the parts manual.

 

[peapvp]

Thanks Guy,

I crossed A5 R3 to a newer Version with the same spec as the original one.

There are two options:
1. Inductive (cheaper)
2. Non Inductive (more expensive)

My recommendation would be to use the Non inductive version as they are better suite able for DC Environments where inductive loads are switched like this particular application.
Inductive Wire Wound Resistors are better suite able when they limit the current to a purely resistive loads

I usually upgrade parts during repair / overhauls