Power Supply Problems

[David R]

When we acquired a boat, it had a small 300W inverter of dubious provenance which just about coped with powering the telly and fridge.

 

We now have a 1KW Sterling inverter which is excellent in all respects however, we now are having the following problems:

 

1) A DAB radio (with an off-board 240V>9V power supply) display flickers constantly and audio also breaks up. I have tried running this on domestic 240v and with a replacement power supply with the same fault.

 

2) We had an LCD TV that also has an off-board supply (240V>12V) - again the picture breaks up. Have also tried this at home with domestic 240V and a good digital signal - same problems.

 

I don't believe this has anything to do with the change to the Sterling inverter since I was aware of the TV fault at the end of last season (and the end of the old inverter!). I have a nasty feeling that the old inverter has somehow affected the power supplies for these two bit of equipment which in turn have damaged the actual equipment. Is this possible?

 

If this is the case, can the same thing happened with the new inverter (quasi-sine) or is it that the power supplies are not suitable for use with inverters?

 

Any clues please?

 

Thanks

 

David

[ThePiglet]

I dunno about the faults, but wouldn't it be more efficent to run these devices from the 12v supply? Think of all the power you're losing taking 12v to 240v then back to 12v (or 9v) again!

Maplin do some 12v to 12v/9v adaptors if the appliances are sensitive.

[by'eck]

Well you have proven to yourself that both these devices have their respective faults when powered from the mains, so the problem is not with your inverter supplied AC. As they are both powered via adapters it seems highly unlikely that they have been damaged by your previous inverter either.

 

Both are radio devices though so are reliant on a good signal. The recent fine weather coupled to cooling in the evenings can lead to phenomena known as temperature inversion which can "bend" radio signals. You may have noticed excessive pixelation with digital TV pictures around or before dusk some evenings - often this is the cause. We noticed distortion recently for the first time from our DAB radio as well - I'm guessing this may have been the cause.

 

In any case I would look elsewhere for an answer to the problems.

[Ark Right]

The recent fine weather coupled to cooling in the evenings can lead to phenomena known as temperature inversion which can "bend" radio signals.

.

 

When the guys come round who know about his stuff I bet it has nothing to do with the weather (presumably David's other equipment at home was working perfectly when he was testing the faulty stuff from his boat) and the equipment has been damaged by poor power supplies.

Cheers

A

[Chalky]

Did you power both of these devices from the inverter on the boat or from their mains adaptors? If you powered them from their adaptors then it's unlikely that you've damaged the units. If you've powered them directly from the inverter that you may have damaged them. Inverters can work in a number of different ways. Some generate a high voltage rail and then use power transistors to switch the high voltage rail to produce the waveform. Others switch at higher speeds and use switchmode techniques to generate the mains waveform. It is possible for a faulty inverter to produce a higher voltage than expected. This could damage the power supplies in the units if you're unlucky.

 

I agree with Richard about the atmospherics. The DAB radio in my car has dropped out more than usual recently and the terrestrial Digital TV has also had a few moment.

 

If by display flicker on your TV you mean that the display goes very blocky or freezes momentarily then this is loss of signal - the audio will also mute at the same time. If the whole display goes off then back on then its probably a power supply fault.

 

The flickering of the DAB display (unless it's telling you its lost signal) suggests a power supply fault.

 

It'd be worth talking to neighbours who have similar equipment and see if they're getting the same problems. If they're not then I would suggest you may have an equipment fault.

Edited April 24, 2011 by Chalky