# Hymer B590 Starline electrical problem: no 240V power to sockets



## grahamcooke (May 13, 2011)

I own a Hymer B590 Starline, left hand drive and registered in the UK two years ago. I have a problem in that when I am on hookup mains power is no longer fed to the sockets inside the van.
However, if I turn on the inverter (whilst on hook up) 240V power to the sockets is restored and I can run appliances as before. 
The problem is of my own making. Two days ago I overloaded the circuit by using a microwave, kettle and electric heater at the same time. All suddenly stopped working although neither of the two trip switches tripped out. 
All the 12V appliances work. There is no problem with the lighting, satellite dish, television, all of which continue to work whilst I am on hookup. They work when I detach the external power supply and turn the inverter on as the leisure batteries are fully charged. The fridge freezer continues to work when I am hookup and the display tells me that it is working on 240V power, rather than gas or 12V which only kicks in when the vehicle is in motion.
Can anyone offer a solution please or advice as to where I can consult a local motorhome technician? I am in Southern Spain with my wife until mid April and whilst I can live with the problem for the moment it would be great to find a fix.
I shall give a more detailed explanation of the vans circuitry below and my unsuccessful attempts to find the source of the problem.

Steps taken:
1 I have inspected and tested with a multimeter all the fuses in the transformer/rectifier, on the starter battery, and those fitted next to the living area batteries and found them to be OK. 
2 I have similarly tested the external power supply. The panel above the door confirms that external power is coming in to the van and the hook up cable gives a clean connection.
3 There are two 240V circuit breakers described in my manual as 'fuse boxes with safety cut out and F1 switch'. The first one is located in the wardrobe where the power comes into the van. I have taken the cover off and tested it. It is working satisfactorily. Power is coming in and going out.
4 The second circuit breaker is located under the floor and next to the Waeco MSP1512 inverter. The second circuit breaker serves the inverter and is working satisfactorily. Once again I tested it to find that it is working satisfactorily.
5 The Hymer manual wiring diagram shows that the 240V sockets in the van are fed directly from the Waeco inverter. 
As the sockets used to work satisfactorily on hook up with the inverter turned off before I overloaded the circuit I am wondering if the inverter might be the source of the problem with an internal component burnt out or something similar. In other words is there a relay switch within the inverter which allows 240V power to pass through when it is turned off?
Alternatively am I barking up the wrong tree and there is another likely explanation?

Any advice and how to fix it would be appreciated. I hope that it does not mean a new inverter as having looked on Amazon I see they cost circa £950.

Finally, if anyone knows of motorhome engineer here in the Malaga region I shall appreciate contact details please. I shall post separately with this request. Many thanks.


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## rayc (Jun 3, 2008)

A quick question. When everything was working ok how did you change the power source for the sockets from mains fed to inverter fed?

If it was done automatically i.e. the inverter fed the sockets until mains power was available then I suspect integrated mains priority circuit within the inverter may be faulty. Are you absolutely sure that mains power is going into the inverter?


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## rayc (Jun 3, 2008)

I have checked the circuit and when mains is present at the input then a relay operates and feeds the mains directly to the output. 
If no mains is present the relay drops out and feeds the output from the inverter section to the output sockets. 

I have never used one of these inverters so I assume that if the inverter is switched OFF that the mains is fed from the input to the output. When the inverter is switched ON then mains takes priority over battery. In any event if you have mains going in then the mains relay should operate and feed the input to the output.


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## grahamcooke (May 13, 2011)

*Hymer electrical problem*

Rayc
Many thanks for your two replies.
When the electrics were working properly - two days ago before I overloaded the circuit - I would merely hook up with the inverter switched off and 240V power would be supplied to the sockets. This does not happen now.
When the van is on hook up I would have no reason to switch the inverter on. If I did, (whilst on hook up) I would still get mains power to the sockets.
I think you have confirmed my suspicions thank you.
Regarding your second response if the relay is not working when mains is present does this suggest that no power is being fed to the battery charger? 
Does anyone know if these Waeco MSP1512 inverters can be fixed? Dometic has taken the company over and I can't see any advice on the subject on their website. Regards


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## rayc (Jun 3, 2008)

grahamcooke said:


> Rayc
> 
> Regarding your second response if the relay is not working when mains is present does this suggest that no power is being fed to the battery charger?


No. It is an overall generic schematic drawing and shows the additional circuits [2] being fed via F1 2, which is the isolation MCB that you have previously said you have checked. On your MH the additional circuits e.g. charger, fridge etc. could be fed via a completely separate MCB.
You are interested in what is happening in block MSP. If mains goes in then the relay should feed mains out.
Have you checked that mains is definitely going in on the input terminals? Does the relay click?

I have not looked inside one so I do not know if it can be fixed. The schematic looks fairly simple but I've no idea whether it is a PCB with control electronics etc.There are agents in the UK and a search shows that the well respected Eddie Vanbitz supplies them. They are knowledgeable and helpful and hopefully you could get a response from them. I have found best by phone or email as opposed to the web contact form. https://www.vanbitz.com/


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