Fender HR Deville Had a Drink.

[g1]

My feeling is that cleaning off the carbonized material and then just leaving a clean hole behind is OK. The dielectric strength of Air is 3kV/mm so there won't be a problem and the extra effort to fill the hole is unnecessary.

Not to disagree with you but sometimes I want something to put on metal or a solder joint. And just to point out, that spec is for mil (thousandth of inch), not mm.

[The Dude]

I think Tom was referencing this case in particular where the burn is between traces and no connections need to be rebuilt. I'm ok with just leaving the hole. If you need to rebuild some connections, the corona dope is certainly a good idea. I don't see it as necessary in this case. So there, you "old resentful repairman".

[Pryde]

Just curious what about something like CA glue to "fill in" a small void? I thought about it for a moment and then decided to just stick with silicon.

[Enzo]

Tom beat me to it, I see no reason to fill the hole, air is a better insulator than the other stuff. In fact in some pc board power tube socket areas they actuall make small slots in the board on either side of pin 3 to help prevent arcs. CRT video monitors are sometimes made the same way. I have also seen slots cut in the circuit boards of SMPS for the same reason.

[bsco]

Tom beat me to it, I see no reason to fill the hole, air is a better insulator than the other stuff. In fact in some pc board power tube socket areas they actuall make small slots in the board on either side of pin 3 to help prevent arcs. CRT video monitors are sometimes made the same way. I have also seen slots cut in the circuit boards of SMPS for the same reason.

Actually I never knew that......Thanks for the mini lesson......Tom suggested the HV corona dope so i am going to pick some up....for the amount of times I would have to use it, it would last me a lifetime....

[Enzo]

I have a bottle of corona dope I bought back in the 1970s. I never used even half of it. Exactly when it dried up into a solid red lump in a jar I do not know.

[bsco]

I have a bottle of corona dope I bought back in the 1970s. I never used even half of it. Exactly when it dried up into a solid red lump in a jar I do not know.

Once the air gets inside the bottle that stuff happens but it does take a long time for it to occurr

[g1]

Ok you guys. Uncle.

[Tom Phillips]

I have a bottle of corona dope I bought back in the 1970s. I never used even half of it. Exactly when it dried up into a solid red lump in a jar I do not know.

Same thing happened to me. In fact I recently cleaned out many containers of such things as glues, paints and caulks that had all gone bad sitting in the shop.

[TimmyP1955]

If the carbon is gone, you are ready to go. If it's not gone, I should think that covering it up might not do any good.

[g1]

Yes. It will now be no more likely to strike an arc than it was in the original instance where it struck an arc.

So what does one do in cases such as newer boogies where the traces are just too close together and arcing is not uncommon? Shave the traces? Re-design a board?

[Tom Phillips]

...So what does one do in cases such as newer boogies where the traces are just too close together and arcing is not uncommon? Shave the traces? Re-design a board?

Well...Someone should redesign the board but that is too much to ask of the repair tech. I say that when a design has devolved to the point where the product is inherently unreliable then users will abandon the product in favor of another brand. The left over amps will then be available at scrap prices for others to strip down and reuse the chassis, cabinet and transformers.

Edit: The practical approach for the Boogies that are prone to arcing is to keep the internals really clean. Same goes for tube sockets. Especially if someone has used an inappropriate cleaner or contact spay that left a residue that then starts to collect dust

[Chuck H]

Yes. It will now be no more likely to strike an arc than it was in the original instance where it struck an arc.

So what does one do in cases such as newer boogies where the traces are just too close together and arcing is not uncommon? Shave the traces? Re-design a board?

I suppose if there's room between the pins one could use a Dremel to saw a slot on either side of any HV pin?!? I might try that if I ever had to deal with a failed one. Has to be better than some of the repairs I've seen. Like cutting out that piece of board and hard wiring all the connections with lead wire.

Oh... Here's a thought. One could just cut out the HV pin and cut through the trace an inch above. Then hardwire only the HV.