Burnt PWB Repair Advice

Shane73

Member
2016-02-18 1:57 am
I have an Orion XTR2200.1 that had several electrolytic capacitors fail and then flair up. The result is a burnt hole in the pwb. Outside of the damaged board and capacitors, the amp appairs to be fine, the power and output fets do not show as shorted on a dmm. What kind of an epoxy can I use to fill in the damaged board and can I use conductive copper tape to create a new lead?
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Ideally you should remove the carbonised PCB (drill it out). This is particularly important in high voltage areas to avoid further damage due to the burnt board becoming conductive.

Epoxy putty used to be a favourite for this kind of work. Conductive tape may not be able to handle much current, you might be better laying tinned copper wire in place of the damaged print. If the hole is very small then there is no need to fill, just support the replacement part by its leads and secure the part (to make vibration proof) with silicon rubber type compound.
 

Shane73

Member
2016-02-18 1:57 am
The hole is approximately 1/4" wide x 1/2" long. The lead is 3/4" wide where the board burnt through. I had thought about adding a thin layer of solder over the copper foil to increase its load carrying abilities. What kind of epoxy should I use. I had considered jb weld but worry that it may be conductive.
 

Perry Babin

Member
Paid Member
2003-11-20 11:01 am
Louisiana
www.bcae1.com
JB weld is what I generally recommend. If you place a piece of packing tape on the other side of the board, it will leave a smooth finish.

Leave the edges of the hole rough and work the JB weld into the fibers on the board before pouring into the hole. Let it set up a full 24 hours before removing the tape. If you have any fiberglass cloth, cut some fibers and mix into the JB Weld while mixing it.

As was stated above, remove 100% of the carbonized material.

I'd use wire to bridge the gaps instead of copper tape but you'll have to decide what you use.