all charged out.

[r8516874]

Clive,

 

It is definatly a mk 3. It says so on the black plate on the side of the case.

 

I'll change the battery in the multimeter and do another set of readings. Aparently the battery has never changed, so says my father. I'll also get another multimeter from work.

 

I'll give the bulb and battery method a go and see what I get. When you talk about the heatsinks where on the generator do you mean?

 

The generator or panel didn't smoke burn or overheat. But I remember doing some welding in the footwell. I disconnected the generator, panel and batteries but could I have still caused some damage. Surly if that is the case the diodes would have broken down giving less resistance not more.

 

Can the generator/panel be repaired if I find a faults with them? New diodes, reisitors, etc.

 

Hope we get there eventually,

Jim

[fv1609]

Jim, is it moving coil meter or a digital thing? I find digital things if they don't have something definitive to measure rather than be honest about it & display 0000000 they tend to gibber around trying to look as if they are doing something useful. I find a moving coil meter is more honest, particlarly as very precise readings are not needed here. I'd sooner have an approximate reading that I can trust than an erronous one to 6 decimal places! Digitals are good at adding uncertainties into areas where uncertainties exist already. I do use digitals for exacting measurements but when searching for ball park readings I like a thing with a needle that moves, otherwise my brain spends it's time trying to convert changing digital displays into a mental analogue display.

 

Yes diodes & resistors can be replaced I have seen power diodes a few days ago for about £1.50.

 

Yes I would have thought semiconductor diodes failing will usually convert to conductors quite easily. Yes welding can be a problem. I see you disconnected the plugs. Did you reconnect them all before running the engine as peak voltage produced are said to damage the diodes?

 

Heat sinks are here

Edited February 12, 2010 by fv1609

[r8516874]

I'm afraid it is a digital multimeter. I will try using the battery method and see if that can help me.

If all else fails I'll try and find a coil meter.

 

Yes the plugs were all connected again and the control panel was wired up how ever it was wired.

Where did you see the power diodes? Are they an easy fit? I have a feeling that these diodes could be the cause of my problem's, but I'll Soldier on.

[fv1609]

At least with a battery & bulb its good old fashioned does it/doesn't it technology. If you do have to do tests on the 3 main windings a multimeter of any sort is no good because the resistance is so low & making contact with the prods & their plugs can introduce slight resistance & you'll not know what you are measuring is a short circuit or the winding is ok. The best was is to pass 20 - 40 amps through & measure the voltage accross each coil. Anyway that is something for later maybe.

 

The power diodes I saw for £1.50 were from 'the xmod'. Don't go buying any I haven't cross checked the part numbers yet. To fit you have to pull it apart & when you are in there it would be worth checking the brushes for wear.

 

Last year I saw a dealer who had complete heatsink assemblies with all 9 diodes. I think they were Gen No.10, I would need to check as Gen No.9, which is 100 amps, looks very similar. Although even if it is for that the diodes could be lifted.

 

Replacement just requires unsoldering the wire to the top terminal & unbolting it.

 

I've got Generator Panels coming out of my ears. I am drawing coloured & simplified circuit diagrams for Mk A, 2, 3 & 4. I am trying to make them of identical layout so that improvements get be readily seen & yet the basic principle of operation can be followed on the next diagram having got familiar with the last.

 

It is not helped with the illogical way EMERs for Rovers have been compiled. I now have a situation where 5 resistors around the regulator have the same names but for dissimilar functions. Some of these diagrams are wrong. However I interpret it someone will tell me I am wrong!

 

Anyway back to Paint. Trouble is a couple of the images got saved as 300kb jpgs & rather than 10Mb bmp so as the the neat lines & things have lost their clarity with a peripheral fuzz & a slight grey haze around that. So having to rub out sections & reconstruct it again. At least it gives me something to do in the warm!

[r8516874]

 

I've got Generator Panels coming out of my ears.

 

That sounds rather painful!

 

Are EMER's the military publications? If I know the military then everything is in the wrong place and repeated at least 4 times. Making sure its far to expensive.

 

I'm sure putting heads together can make sense of the mess. But even so it sounds like your making good progress. I'm on the edge of my seat in anticipation, it should make great reading.

 

I've been out working on other machines today and your right, playing with images in paint is much warmer. I have just got the feeling back in my right hand.

The things we do for vehicles we love.

[fv1609]

Are EMER's the military publications? If I know the military then everything is in the wrong place and repeated at least 4 times.

 

EMERs? I'm tempted to answer but there is an overview of them here. In fact four articles! It also covers a bit on their replacement AESPs.

 

http://hmvf.co.uk/forumvb/showthread.php?438-Electrical-Mechanical-Engineering-Regulations

 

Normally a wheeled vehicle would have info in EMER WHEELED VEHICLES. The things like engine, distribultor, generator, generator panel etc would appear in entirely different sections of EMER POWER. The reason for this is that components & units may be common to several different vehicle types & there would be a vast amount of duplication.

 

Unfortunately with Rovers this convention goes haywire. Unusually some of the charging system is included in EMER WHEELED VEHICLES using Rover civilian documents & some that have been rewriiten for military usage. Unfortunately it doesn't cover all aspects. There is some coverage of the the gen & gen panel in different sections of EMER POWER. Even so some of the gen material is also split off into another section under AC charging systems.

 

In addition to that some EMERs were rewritten/updated to appear in AESPs & some only in FAESP format. Furthermore there were descriptions of some aspoects of the system in WO & Army Coded publications.

 

I've got a modest collection of books here that cover pretty well what has been published. But intergrating the information is more challenging particularly where there are contradictions.

[r8516874]

Clive,

I got the results for the battery bulb test.

 

+ve prod on W and -ve on the heatsinks and the bulb lights up. Reversed and it does not.

 

-ve prod on X and -ve on the heatsinks and the bulb lights up. Reversed it does not.

 

-ve prod on F +ve on the heatsinks and the buld lights up. Again reversed it does not.

 

Not what I though was going to happen but that gives us proof that the diodes are doing something inside the generator. I'm still trying to get hold of an AVO to measure the resistance.

 

On a light note how is your new project getting on, all charged up 4? Hope all is going well.

 

Jim

[fv1609]

Jim

That's very good news. A nice clear cut result from a no frills no nonsense test. Not the misleading stuff from a digital meter!

 

I have borrowed a gen & gen panel. To get some newer pictures & do resistance tests in various key points. I started to use a digital meter for this & it drove me up the wall. I was getting varied readings 8-20megs on the PTR pins that have no connection, the trouble is that it is autoranging & not always easy to see if it is on ohms, kilohms or megohms. I will carry out further readings on an Avo 8.

[r8516874]

/I started to use a digital meter for this & it drove me up the wall. I was getting varied readings 8-20megs on the PTR pins that have no connection, the trouble is that it is autoranging & not always easy to see if it is on ohms, kilohms or megohms.

 

Thats exactly what happened to me. I think an Avo is the best bet.

Where is your logic taking you now? I'm a little bit stumped. I thought that at least one of those test would fail showing a fault, but alas I still can't find it.

[fv1609]

Well I think the thing to do know is determine whether conditions exist for power to be generate & then if it is generated why its not coming on the other end.

 

Have you dismantled the gen or can you plug everything back together?

 

Do make sure that the earth straps are in place as the -ve line is not earthed in the gen & nor in the gen panel. It is only after this!

 

If that is ok you need to find if a voltage is present for the field winding & is applied to U & V. So take lid off gen panel & identify leads to those pins & tell me what you get.

[r8516874]

Have you dismantled the gen or can you plug everything back together?

 

I've got it on a bench but I can put it back in the vehicle.

 

Do make sure that the earth straps are in place as the -ve line is not earthed in the gen & nor in the gen panel. It is only after this!

 

Where in the generator panel is the earth cannection? or the battery connection for that matter. I only have a really rough Idea where things were connected to. Could you do me a picture of the 'outputs' of the generator panel so I can make sure its wired up correctly.

 

Lets hope we find something.

[fv1609]

Leave the gen out, then just work on the panel.

 

I'm leaning towards basing it all on not using resistance readings in the main. But to use voltage measurements in the gen panel.

 

C on the gen panel is -ve follow this to the shunt box & you should find it is earthed sooner or later. If you are happy this is earthed connect voltmeter -ve to earth then turn the ignition on.

 

Put the +ve prod to pin F on the input that should read 24v.

 

Then on the put +ve prod on pin X it should read zero press the relay arm down (as is if it magnetised) then should read 24v.

 

Put +ve prod in V & you should get a reading. Now I don't know what that will be but I imagine it would be 10-20v. This because nowhere can I find a spec for this CAV 'N' Type regulator.

 

Then press the regulator arm down or up not sure as its not front of me & it should go up or down in voltage. I need to sit down & work out with Kirchoffs laws what effective resistance is placed in the two modes for this potential divider. But that's a little way off.

 

Let me know what you get.

[r8516874]

Clive,

I think we may have found some faults.

 

With -ve pin on earth and +ve pin on F I read no volts.

 

Then +ve pin on X and the relay arm pressed down it showed 24V. As the relay was released the voltage started slowly dropping.

 

With +ve pin on V there were no volts shown.

 

These readings would sugest that the generator panel is at fault wouldn't it? Is it possible to point the finger at a component and then replace it? Or shall I try and find another panel?

I have attached a picture of where my earth wire is connected inside the panel to confirm it is in the right place. (indicated by the arrow).

[fv1609]

With -ve pin on earth and +ve pin on F I read no volts..

 

Yes it should be zero, I was talking bollox.

 

I should have said, when you measure the volts on V, press the main relay down. Otherwise it will be zero.

 

If it is earthed inside the panel Mr Bodger has been at work. It should be earthed outside after C leaves the panel, anyway it will work as long as the gen panel itself is earthed well.

 

If you still get nothing on V still then it is either total failure of the regulator (in both windings which is unlikey, failure of one winding would still give some current to flow) or a failure of the load compensating resistor (failure of the other 3 resistors would still allow it to work pass some current)

[r8516874]

I've just tried again and I got no volts on F at all and the same goes for V with and without the relay arm pressed in.

i checked the earthing for the panel casing and it is good.

I guess this gives us some clue as to what is going on.

A new panel it maybe?

 

Jim

[fv1609]

Jim don't worry about F at the moment.

 

You're absolutely certain you are measuring V not U? As that would be zero.

 

So with -ve prod on C or W which should equate to earth & with you pressing to close the relay tell me what voltages you can pick up on the letters marked below adjacent to the nearest terminal or soldered joint.

 

[r8516874]

Clive,

I got no volts on any of the terminals you labled in the picture.

The ignition was on and the relay arm was pressed and I checked with it not pressed. The generator was not connected, nor was the cable to the generator.

Does this mean that the battery power in could on the wrong terminal no putting the volts where we need them?

[r8516874]

ps check for volts from U and V and neither had volts with the relay arm pressed.

[fv1609]

Jim the ignition need not be on & that's fine with the gen cable unplugged. So if you are getting 24v on pin X when you press the relay down & nothing on those points I labelled.

 

Then I have found your problem! You have a fault in the load compensating resistor! It has either a burnt out wire or the connection to it has unsoldered. Although it is only 0.5 ohms it does get very hot indeed & sometimes the solder can melt. The resistor is underneath the regulator unit.

 

 

If you trace the thick blue cable from pin X marked X1 it goes to a choke. Underneath that there is a much smaller yellow wire that heads back under the thick cable & disappears underneath through a notch in the side of the board. To there it goes to the 0.5 ohm wire wound resistor. It probably has failed at that point.

 

If you look at the other end of the resistor marked X that corresponds to point X on the first picture. So if you got no voltage at point X there can be no other explanation than failure of the resistor or its soldered wire. You will always see evidence of intense heat around it.

 

The fiddly bit is dismantling the board. I think you will have to remove the dividing screen & unscrew both boards. Take lots of pictures to remind you where things go. A fiddle or you can buy a new panel from the xmod for £180 I think. Seems expensive for the sake of probably a failed soldered joint.:-)

[r8516874]

clive, your one hell of a man.

I'll take the fiddle with the boards. I'm going to try and tackle it now i'll let you know what happens.

[fv1609]

Yes good man go for it. You will derive great satisfaction from the exercise, save a lot of money & learn quite a lot as you. If the worst comes to worst & you make a complete mess of it you have lost nothing in trying rather than fork out for another at this stage.

[r8516874]

Clive,

Of cause you were right.

There is no connection from point X to the board. Where is it ment to connect to and can i just solder a new bit of wire in from point x to either the board or the next resistor?

[r8516874]

Sorry clive in my haste I miss read you. is the resistor connected only at one end, circled? Because if that is so I think my resistor must have failed.

[fv1609]

Jim the thing about that resistor is that is mounted on brackets.

 

But on the lower end there is no electrical connection between the yellow arrows & you can see the yellow wire (that comes from the choke) soldered on, this is the weak spot.

 

On the other end the mounting & the resistor are soldered together connecting the purple arrows.

 

 

Then you can see the purple arrow on here where it surfaces through the terminal to supply the regulator itself.

 

 

The problem is that the panel I have here has no continuity through that resistor either!

 

This is just a thought, not so much for a permanent bodge but for diagnostic purposes. If you could attach a high wattage 0.5 ohm resistor between the +ve choke & the purple arrowed terminal it should all spring into life!

 

How to get a high wattage low value resistor is a problem. For those sort of things I used to use some wire salvaged from an old electric fire & with an ohmeter measure off the length to give the required resistance then mount the ends in a ceramic terminal block. I suppose you could get some insulated fine wire & choose 0.5 ohms & wire it in temporarily. Then you can get volts to the regulator. Then volts to the field & then output!

 

That will prove the point befre having to dismantle it. Even when you do a proper repair the resistance wire is often difficult to solder & the connection may have to be clamped.

[r8516874]

clive,

done it.

I've got 28volts again. Your a star.

I've put a bit of wire accross the resistor to short it out, the wire has about 0.3ohms of resistance. I take it will run like that.

What can I do about fixing the problem?

All my thanks,

Jim