Hi, thanks for reading.
I am blowing fuses on my capstan motor ( in line 5A 240v fuse mod), i kind of left the fans off by accident following replacement of fans with external psu computer coolermaster fans.,(silly I know)...
So now after a 4-5 hours (fans on) the fuse blows. I suspect stressed power transistors ( the 3 x npn, 3 x pnp 220v 15A to3 style) in MDA.
Originals are:
2SD552 (NPN) and 2SB552 (PNP). My local electronics shop (Jaycar) has something close 140V, 20A , they are MJ15003/MJ15004 ...
The MDA's run on +-40v rails...
Were the originals selected for performance or because that's what was cheaply available in the design phase? ie. is 140V ok?
I suspect the answer has something to do with peak current draw and resistance...
Thanks.
I am blowing fuses on my capstan motor ( in line 5A 240v fuse mod), i kind of left the fans off by accident following replacement of fans with external psu computer coolermaster fans.,(silly I know)...
So now after a 4-5 hours (fans on) the fuse blows. I suspect stressed power transistors ( the 3 x npn, 3 x pnp 220v 15A to3 style) in MDA.
Originals are:
2SD552 (NPN) and 2SB552 (PNP). My local electronics shop (Jaycar) has something close 140V, 20A , they are MJ15003/MJ15004 ...
The MDA's run on +-40v rails...
Were the originals selected for performance or because that's what was cheaply available in the design phase? ie. is 140V ok?
I suspect the answer has something to do with peak current draw and resistance...
Thanks.