old PTC substitution
 

Hi all,

I'm repairing an old Commodore 1702 CRT monitor.
The PTC driving the degauss coil desoldered itself from the PCB, probably
it was too hot (missing solder from the "common" pin of the two PTCs).
This PTC (dual type, one across the 240V line, one in series with the coil)
is marked CE 40595-1 / 4 0 0 3 / TDK (on three different lines).
The degauss coils measures 12 ohms at DC.
I haven't found any reference about this PTC so I can't decide if it's good
or not. It measures 6 ohms in the coil side and 126 ohms in the AC side when
cold. The only service manual I've found for this monitor lists a JVC part
number for the PTC that gives no results on google. However the PTC I've
found on the monitor PCB look the original one since the soldering on the
pins (the ones that didn't desolder themselves) looked original.
I'm tempted to put a 18 ohms (on the coil side) standard TV PTC on it (the
C180N kind), but I seek suggestions and hints.
Thanks in advance

Frank IZ8DWF

old PTC substitution
 

On 02/02/2016 12:00, frank wrote:
Hi all,

I'm repairing an old Commodore 1702 CRT monitor.
The PTC driving the degauss coil desoldered itself from the PCB, probably
it was too hot (missing solder from the "common" pin of the two PTCs).
This PTC (dual type, one across the 240V line, one in series with the coil)
is marked CE 40595-1 / 4 0 0 3 / TDK (on three different lines).
The degauss coils measures 12 ohms at DC.
I haven't found any reference about this PTC so I can't decide if it's good
or not. It measures 6 ohms in the coil side and 126 ohms in the AC side when
cold. The only service manual I've found for this monitor lists a JVC part
number for the PTC that gives no results on google. However the PTC I've
found on the monitor PCB look the original one since the soldering on the
pins (the ones that didn't desolder themselves) looked original.
I'm tempted to put a 18 ohms (on the coil side) standard TV PTC on it (the
C180N kind), but I seek suggestions and hints.
Thanks in advance

Frank IZ8DWF


Any room for a/few suitably rated polyswitch/s as a backup in case it
doesn't drop out?

old PTC substitution
 

N_Cook wrote:


Any room for a/few suitably rated polyswitch/s as a backup in case it
doesn't drop out?

hm, I *could* find room for a couple of them, that would prevent solder
melting in case of failure, but still I'd like to replace the original
PTC if it's faulty.

Thanks
Frank IZ8DWF