Surge Recovery - Burned PC board issue. Techs?


There is a small area arround one of the valve-sockets after surge that was fryed with leads to the cathode feed elements 47uF/100V cap, 1k resistor and 10Ohm bias-resistor.
The cap in fryed area has a voltage 53.4uV drop to 10mA current(I assume it's damaged)
I've also measured cathode feeds for the different bulbs and they seem to be 2% less of the nominated value while the manufactured tolerance is no less than +-0.25%.
My cautions are that even if I replace the damaged elements the fryed PC board area can have an unwanted voltage drop.
Should I somehow cut out this area as whole and wire-up the surrounding elements instead?
marakanetz

Showing 1 response by marakanetz

Sean, Your help is always appreciated!
1.Fortunately the PC-board is not double-sided and I don't have to count on the capacitance between the sides of the PC-board! Tracing the signal path is relatively easy for me as I can open the other monoblock that is OK:)
2.Unfortunately the fry-hole is sufficiently deep(but not large), conductive and inflict the supply voltage to enter the signal flow path. I probably might have to drill it completely out and If it's not the case, what is the best chemical that I need to use to exterminate and clean all the carbon and how I can acquire one? At least I might have to clean the carbon dust arround the rest of functioning elements and the board.
3.What gauge of jump-wires should I use if the DC supply of VTL is 50V on the cathode? The leads on PC-board are 4mm on the signal path and 5...5.5mm on the ground path.
5.The cap's body as well as resistor body is damaged and fryed arround the surge area and I will order them just in case. I know that there could be some tolerance on the caps but I believe that 53uV for 10mA current is large enough drop whad'ya say?