Markon 240v generator repair - advice needed please!

[bassplayer]

My Markon 240v generator has given up the ghost. My engine drives it using a belt system. It still spins up fine but no 240v output anymore at the generator (I.e not tripped out at the breaker end).

 

Can anyone recommend someone in the Herts/Beds/Bucks area who could look at it and fix it? Someone recommended the guy at Willowbridge but his man couldn't do it.

 

It's out of the boat as there is little room in situ to work on it, so it will need a test rig of some kind to spin it up. I'm happy to take it anywhere within 50 miles of Milton Keynes.

Edited December 20, 2013 by bassplayer

[Keith M]

Is there a capacitor in the termination compartment

 

If there is I suggest that it is tested

 

Keith

[Tonka]

I took my Markon Sawafuji to Erik in Maidenhead. It was expensive to repair though. They have other branches though and may have one nearer to you

[BEngo]

What sort of Markon is it?

 

If it's the old SCN type with a separate AVR there are some simple tests you can do to ascertain what is duff. I have the handbook somewhere which details them, but I'd start by looking at the brushes and the connections to the AVR board then checking continuity of the two stator windings and the rotor winding. If all is OK then disconnect the AVR and with it going apply 12V across the brushes. That should produce an output. ( The normal running AVR voltage is up to 63 V IIRC). If that's OK it's worth putting the AVR board back and seeing what happens, because the 12V input will have re-magnetised things..

 

If it's the board it should be repairable, as it's all discrete components, but I've no idea where to find a specialist who can remove the weather proof coating, repair the board and re-apply the coating.

 

 

N

[Rufford]

Fit a new capacitor (available from rapidonline), failing that it will be the diodes.

 

If you are prepared to wait a few months I beleve Markon are opening their new factory/warehouse soon and restarting production - they used to sell the complete generator end for around £100

[bassplayer]

It's a Markon SC21c. About 20 years old.

 

I do have a copy of some kind of manual showing a few circuits. The trouble is there don't seem to be any pictures so you can relate the diagrams to the actual generator and circuit board.

 

I've got a DVM but would need a quite a lot of guiding through if I did it myself. I used to do some electronics but it was always 5v stuff, this 240v stuff is dangerous you know!

[dunfixing]

if it works like a normal alternator, it would have some sort of voltage regulator,that feeds the stator. if there is no output it could be the voltage feed to the stator that is missing, or just need new brushes.

a quick test is turn it by hand quickly, the drive spindle will be magnetic if it is ok. test magnetism with screw drive etc.

sorry cant help more. but not in your area.

Edited December 20, 2013 by dunfixing

[jake_crew]

I have heard that if the genny hasn't been used for some time, it loses the remnant magnetism in the core which "self excites" it.

 

A 12 v dc battery across the CORRECT diodes in the diode pack should kick start it.

[bassplayer]

I took my Markon Sawafuji to Erik in Maidenhead. It was expensive to repair though. They have other branches though and may have one nearer to you

May I ask how much?

What sort of Markon is it?

 

If it's the old SCN type with a separate AVR there are some simple tests you can do to ascertain what is duff. I have the handbook somewhere which details them, but I'd start by looking at the brushes and the connections to the AVR board then checking continuity of the two stator windings and the rotor winding. If all is OK then disconnect the AVR and with it going apply 12V across the brushes. That should produce an output. ( The normal running AVR voltage is up to 63 V IIRC). If that's OK it's worth putting the AVR board back and seeing what happens, because the 12V input will have re-magnetised things..

 

If it's the board it should be repairable, as it's all discrete components, but I've no idea where to find a specialist who can remove the weather proof coating, repair the board and re-apply the coating.

 

 

N

Thanks, things to try there if I can find a way of spinning it up. I've got very limited space when spun up by the engine but if I open it up and work out where everything is I might be able to do this in situ.

Fit a new capacitor (available from rapidonline), failing that it will be the diodes.

 

If you are prepared to wait a few months I beleve Markon are opening their new factory/warehouse soon and restarting production - they used to sell the complete generator end for around £100

Thanks, where is that capacitor located and what's the spec so I can order it. It's worth a shot...

I have heard that if the genny hasn't been used for some time, it loses the remnant magnetism in the core which "self excites" it.

 

A 12 v dc battery across the CORRECT diodes in the diode pack should kick start it.

Thanks, did wonder this. Residual current I believe. The problem I have is locating the exact point I need to do this. I work much better with pictures!

[Semitrad]

I have heard that if the genny hasn't been used for some time, it loses the remnant magnetism in the core which "self excites" it.

 

A 12 v dc battery across the CORRECT diodes in the diode pack should kick start it.

 

 

Our travelpower generator used to suffer like this. I was usually able to re-energise it by running the engine as fast as I felt comfortable with and switching a large load (kettle) at the same time.

[Tonka]

It cost me £330 approx about a year ago which involved re-bearing it and re-attaching the fan which had come loose plus a static check at the end. Hope that helps

[GUMPY]

It cost me £330 approx about a year ago which involved re-bearing it and re-attaching the fan which had come loose plus a static check at the end. Hope that helps

Before Markon closed over here in 2012 I bought a complete 6kva unit from them for less than that it was cheaper than repairing the old unit.

[Tonka]

It probably would have been cheaper to buy a new unit but it would probably had to have a new controll box fitted and also a welder to make a new mounting for it so the whole cost would probably been more

[GUMPY]

It probably would have been cheaper to buy a new unit but it would probably had to have a new controll box fitted and also a welder to make a new mounting for it so the whole cost would probably been more

wasn't better it was a like for like markon alternator replacement. Three wires, half a dozen bolts to remove the old one, then bolt the new one on.

[Biggles]

I have just removed a fully working SL105g if you are interested. I also have 2 AVR's one is the basic 4 connection Newage which is fine or a super duper better 6 wire connection one.

 

It does need new brushes though as I've damaged them. Fool that I am.

 

PM me if you are interested.

[bassplayer]

It cost me £330 approx about a year ago which involved re-bearing it and re-attaching the fan which had come loose plus a static check at the end. Hope that helps

Thanks mate, might swerve that option

 

 

Our travelpower generator used to suffer like this. I was usually able to re-energise it by running the engine as fast as I felt comfortable with and switching a large load (kettle) at the same time.

..err...I think that's how I broke it....

[bassplayer]

I have just removed a fully working SL105g if you are interested. I also have 2 AVR's one is the basic 4 connection Newage which is fine or a super duper better 6 wire connection one.

 

It does need new brushes though as I've damaged them. Fool that I am.

 

PM me if you are interested.

Thanks for that. I may well take you up on that if I run out options.

Fit a new capacitor (available from rapidonline), failing that it will be the diodes.

 

If you are prepared to wait a few months I beleve Markon are opening their new factory/warehouse soon and restarting production - they used to sell the complete generator end for around £100

Do you know where Markon are setting up their new warehouse?

[jake_crew]

Thanks, did wonder this. Residual current I believe. The problem I have is locating the exact point I need to do this. I work much better with pictures!

 

As I understand it, you locate the hefty bridge rectifier, which feeds the stator.

 

Put 12 V DC across it to energise the stator, but beware of the polarity so that you don't pop the diodes of the BR.

 

Then run the generator and the external stator supply will kick start power generation.

 

This is what I will need to do with mine once its reassembled.

 

I'm also fitting new big capacitors.

[bassplayer]

 

As I understand it, you locate the hefty bridge rectifier, which feeds the stator.

 

Put 12 V DC across it to energise the stator, but beware of the polarity so that you don't pop the diodes of the BR.

 

Then run the generator and the external stator supply will kick start power generation.

 

This is what I will need to do with mine once its reassembled.

 

I'm also fitting new big capacitors.

My mate had a look at it and found that one of the capacitors has blown. We're going to source and fit 2 new ones. The diodes seem Ok. Let's see what happens...thanks for everyone's help....

[bassplayer]

Well just refitted the generator after replacing the blown suppression capacitor. Unfortunately still no output. I was really hoping that was the problem. Oh well, back to the drawing board!

[Tonka]

I am currently trying to source a rectifier for my Markon Sl105. Which is currently with Cox Automotive at Atherstone