Diode replacement

[ss30]

After a bit of advice, I have a 24v wave maker in my marine fish tank and the controller died so I took it apart and where the power connects to the cuircut board the first component is a diode.

I de-soldered the diode and replaced it with a solid copper wire and it now works, I want to put a new diode on the pcb what would be suitable?

The transformer powering it is 24v 2amp.

Thanks

Paul

[coin-op]

You do know that a diode is not the same as solid copper wire ?

[rids]

What's the power plug like ? If it's like a figure 8 (olds tape player type) don't turn it round you got lucky.


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[ss30]

Yes I know what a diode does and I know that a piece of copper wire is not the same.

It's a 24v transformer with a jack plug, not 240 volt!

[Soulassassin]

The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.

[coin-op]

The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.

Also, since there is no rectification, and I'd guess a smoothing capacitor in there somewhere, that will be the next to go. The negative excursions that the diode would be blocking will now reach the capacitor - electrolytics don't like that.

[plug1]

It will be a tvs diode or even ferrite bead , if it works when you short it out its probz a fb .

[CallmeGoose]

i genuinely read this post as "Dildo Replacement" everytime I see it appear on my new posts list.....

[ss30]

The transformer is what makes it 24v (stepped down from 240v). The diodes will probably be what makes makes it DC from AC. Although it works you may be damaging the pump as the DC current may be quite irregular.

The transformer output is 24v dc

[ss30]

i genuinely read this post as "Dildo Replacement" everytime I see it appear on my new posts list.....

Too much time spent on boats surrounded by seamen!

[ss30]

It will be a tvs diode or even ferrite bead , if it works when you short it out its probz a fb .

Thank you plug1 for answering the question

[ss30]

Here is a pic of the diode in place

It's the first component after the power enters the board on the centre pin of the jack plug supplying 24v DC

[tronads]

Looks like one of these to me... http://www.kingtronics.com/diodes-re.../m7-diode.html

[braymond]

I think the fact it's labelled d01 pretty much confirms it's a diode ;-)


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[cosmicma]

looks like a simple protection diode to stop reverse polarity killing the board / voltage regulator
you could leave it as it is if you are confident you will never switch + and - the wrong way round but better to replace it

why it would go open circuit is a bit if a mystery they usually short circuit when they fail

[coin-op]

looks like a simple protection diode to stop reverse polarity killing the board / voltage regulator
you could leave it as it is if you are confident you will never switch + and - the wrong way round but better to replace it

why it would go open circuit is a bit if a mystery they usually short circuit when they fail

Unless it's been severely reverse biased - that would tater it.

[tronads]

why it would go open circuit is a bit if a mystery they usually short circuit when they fail

i would disagree with that and state the opposite....but it has been over 20 years since my electronic engineering qualifications were gained. ive slept since then.

[cosmicma]

Unless it's been severely reverse biased - that would tater it.

it certainly would but they tend to short out unless they fry

looking a bit closer at the board it looks like the left leg of the voltage regulator has gone dry ( dry joint ) which might need a touch with a bit of solder



did you check the diode with a meter ?

[cosmicma]

i would disagree with that and state the opposite....but it has been over 20 years since my electronic engineering qualifications were gained. ive slept since then.

it's a long time for me too mate they were still teaching fault finding on thorn 1500 hybrid chassis when i was at college things have moved on a long way since then ( thank feck )

my recollection of diodes in power supplies tend to short circuit and fry because of it which i suppose ultimately leads to an open circuit but in this case if the photo is of the diode when it failed it looks to me as if that wasn't the problem unless it did indeed go open circuit
if that is a dry joint on the regulator that would be the cause of the board failing but not the diode

hard to say from a photo

[tronads]

Yes, it was its final state, and state when fault finding i was referring to.