Is true that a pc sync cord damages the internal circuit?

Is true that a pc sync cord damages the internal circuit due to huge power discharge from a studio strobe???

No, with any modern strobe unit the trigger voltage would be under the 250v safe voltage tolerated by modern dSLRs

Also, it's not just studio strobes that can be a problem. Some older speedlights can also send too much voltage back through the PC cord.

Those concerned about damage from flash voltage can use a Wein Safe Sync voltage regulator.

Fellipe de Paula wrote in post #6266946
Is true that a pc sync cord damages the internal circuit due to huge power discharge from a studio strobe???

1) State the camera you own and the flash device you wish to link.

2) Only use a safe sync if it is necessary. The safe sync's provide protection where needed, but have there own menu of issues. So, they should be avoided and not used it a situation where their protection is unnecessary.

3) Issues with excessive sync Voltage should be address in a focused manner based on knowledge of the actual gear in play, not a reaction to fear based on vague possibilities.

Enjoy! Lon

Your gear list includes one body and one flash unit - A 5D and a 580EX II.
Both of these have a PC socket.
Hooking them together with a cord won't hurt anything. There's a reason camera manufacturers put those PC sockets on them.