Well, the *ah* fuse is a time-delay and the *al* fuse is an instant.
This means that the *al* fuse will very most likely blow at start very
most likely every time.
However "blew ... to bits" is indicative of something more serious
than the wrong fuse. So: find the correct Time Delay fuse and try it
ONCE (1-Time). If it holds, move on with caution. If it blows again,
seek professional help.
Peter Wieck
Wyncote, PA
I don't think that is right. It's the "T" at the start which determines
whether or not a fuse has a "T" ime delayed action, and the "H" or "L" at
the end specify whether it has a "H" igh or "L" ow breaking capacity - that
is the maximum current that it can safely interupt. The fuse in the front
end of a SMPS is usually a "T" rated HRC type, often with a ceramic body to
prevent potential shattering. The "A" preceding either of these letters is
merely for "A" mps. So the OP's original fuse of T3.15AH, is a high breaking
capacity time delayed 3.15 amp fuse, which is exactly what I would expect in
that position.
As far as I am aware, low breaking capacity fuses are typically rated 35A
and high breaking capacity ones at 1500A. I think all combinations are also
available, so you can get a "T" rated fuse in an "L" or "H" version, and
likewise for an "F" rated type.
FWIW, an "L" specified fuse should still work ok and should not vapourise
under normal circumstances. The fact that it does, would indicate an
additional problem which is causing a current draw which exceeds the fuse's
*rating*, which is the only important factor as far as the fuse failing is
concerned. As long as they are both "T" rated types, the A or H is of no
consequence, except with regard to safety from the glass shattering. As
others have said, the problem is likely to be a bridge diode, line-side
filter cap, or possibly the switching element itself, depending on design.
When the problem is sorted, the fuse should be replaced with one of correct
specification, to maintain the monitor's safety approvals.
Arfa