Jtagging a dead DM500s with serial port

[pdsama]

Hello,
I want to Jtag my dead DM500s clone i searched all over the tutorials and found only Jtag with LPT port or parallel port and the only available thing for me is a serial port i got from an old motherboard i had laying around.
is there is anyway to make Jtag with a serial port instead of LPT ?

[pdsama]

i have done some checking around the motherboard of the Dreambox i found out that there is overheating in L400 and L402 i posted a photo of it (sorry for the bad resolution)
the two of them are overheating excessively
i thought my dreambox was time bombed because of the new image i updated but i think its a hardware problem now that is why i was searching for the jtag
my dreambox main problem is the green light goes on flickering for about 5 seconds or less and then it fades away the box parts is heated do to power in it but no response what so ever i opened it and noticed the over heating problem in this 2 components