Whoo! Able to be online again in short notice because two items
blew out. This stupid little SMD ceramic capacitor
stabbed that transformer!
Was working I turned in for the night before. When I got up,
noticed DSL modem is cold and "dead". Yanked the plug out and
metered it. Nada...and resistance on primary coil is open,
secondary is good. Boooo! This is somewhat odd voltage (16VAC),
grabbed 12AC, snipped it's original plug and took right one from my
junk box and spliced it in.
Huh, modem still sick? Felt heat where it shouldn't be, popped all 4
snaps and looked in, aha, shorted cap easily spotted thing, blackened
on one end and fuse opened in input power section before the full
wave rectifier. :-)
I wondered how this SMD cap die this way, this is first
time I saw insides of DSL Nortel Networks modem. :-) oh, that modem
contains 68HC11 uC.
PCB is decent quality but I'm puzzled at no RF shielding. (!!) The
case is just grey plastic halves, guess that anybody can run
computer guts screaming RF emissions without case. Not smart and
guess what, the manual says place modem about foot away from
monitor. No wonder, no RF tin can.
Cheers,
Wizard and DSL modem bought back from dead. :-D