Circuit Board Surge Protection

I doubt from what you have stated (and failed to state) that you have particularly good odds of being correct about why the thing fails. You are taking a wild guess based on not much, if any knowledge of what you are talking about, evidently.

It is more likely that it is poorly designed at a fundamental level, as so many consumer goods are, when saving 5 cents at the time of building is more important to the maker than long-term reliability. After all, if they kept working you wouldn't need to buy new ones or replacement parts.

=A0I've done research and they are "prone" to doing this, but no one will s= ay why. =A0I believe it to be the stress the components take during the pow= er surge that takes place when the unit is turned on by its toggle switch.

ion circuit that will clip things so the board doesn't blow? =A0I know ther= e is probably an amperage rating that needs found out, but I don't know the= best way to figure that; but the board takes in 110v 60hz straight from th= e toggle switch already mentioned...no circuitry in between the wall plug a= nd the board.

To know why it fails, we have to know what's breaking and why.

It could be line surges, it could be motor spikes, loading, back- generation, or other...

A 1st clue for us would be: which part explodes?

-- Cheers, James Arthur

As the others have said; you've not given enough detail to base a theory on.

Also sci.electronics.repair is the group for this question.

done research and they are "prone" to doing this, but no one will say why. I believe it to be the stress the components take during the power surge that takes place when the unit is turned on by its toggle switch.

circuit that will clip things so the board doesn't blow? I know there is probably an amperage rating that needs found out, but I don't know the best way to figure that; but the board takes in 110v 60hz straight from the toggle switch already mentioned...no circuitry in between the wall plug and the board.

=A0I've done research and they are "prone" to doing this, but no one will s= ay why. =A0I believe it to be the stress the components take during the pow= er surge that takes place when the unit is turned on by its toggle switch.

ion circuit that will clip things so the board doesn't blow? =A0I know ther= e is probably an amperage rating that needs found out, but I don't know the= best way to figure that; but the board takes in 110v 60hz straight from th= e toggle switch already mentioned...no circuitry in between the wall plug a= nd the board.

use a zero crossing' switch like a high power dimmer switch, but always turn on full.

I've done research and they are "prone" to doing this, but no one will say= why. I believe it to be the stress the components take during the power s= urge that takes place when the unit is turned on by its toggle switch.

n circuit that will clip things so the board doesn't blow? I know there is= probably an amperage rating that needs found out, but I don't know the bes= t way to figure that; but the board takes in 110v 60hz straight from the to= ggle switch already mentioned...no circuitry in between the wall plug and t= he board.

Thanks for calling me an idiot and offering absolutely no help at all. Man= , all I know is what I know and it may not be much, but the question of pro= tecting that board from surges, which is a valid cause of failure in any el= ectronic device, is quite valid. If you have any insight into that, thanks= , otherwise, don't say anything. You don't have to call other people stupid= just to make yourself feel smarter, especially when you have nothing helpf= ul to say at all.

. I've done research and they are "prone" to doing this, but no one will s= ay why. I believe it to be the stress the components take during the power= surge that takes place when the unit is turned on by its toggle switch.

ion circuit that will clip things so the board doesn't blow? I know there = is probably an amperage rating that needs found out, but I don't know the b= est way to figure that; but the board takes in 110v 60hz straight from the = toggle switch already mentioned...no circuitry in between the wall plug and= the board.

up. I've done research and they are "prone" to doing this, but no one will= say why. I believe it to be the stress the components take during the pow= er surge that takes place when the unit is turned on by its toggle switch.

ction circuit that will clip things so the board doesn't blow? I know ther= e is probably an amperage rating that needs found out, but I don't know the= best way to figure that; but the board takes in 110v 60hz straight from th= e toggle switch already mentioned...no circuitry in between the wall plug a= nd the board.

Sorry...this was not for you, but for the first reply I received. Again, I= 'm VERY sorry this ended up in your post.

circuit that will clip things so the board doesn't blow? I know there is probably an amperage rating that needs found out, but I don't know the best way to figure that; but the board takes in 110v 60hz straight from the toggle switch already mentioned...no circuitry in between the wall plug and the board.

The usual way of dealing with this involves a device called a MOV or a varistor or a TVP.

We have great heaping bunches of them available at

Every time I mention MOVs, I get corrected that sidacs are what everyone uses now - but as I've yet to recover one from scrapped commercial equipment, I haven't really bothered looking them up.

Sidacs are thyristors, heavy duty diacs, they behave somewhat like spark gaps: low on-voltage. Movs are like zeners their on voltage is higher than the "threshold" voltage. If you use a sidac for protection you need series impedance in the supply to stop it from exploding. They're mainly used for protecting communications lines where the line impedance is enough to limit the short circuit current.