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Re: Help! Marshall 4203 blowing fuses, not PT

2/3/2006 7:19 AM
R.G.	Re: Help! Marshall 4203 blowing fuses, not PT My brain finally dredged up what may be an important bit of info for you. I dimly remember that some Marshalls have the bias supply connected so that when the standby switch is turned to the sound-off position, the bias supply is turned off as well. When the standby switch is turned to the play position, the main B+ comes up faster than the bias supply, and so there is a short time when the tubes are unbiased with the heaters hot. This makes for a big slug of current that diminishes as the bias supply comes up. That kind of thing could definitely pop a non-slow-blow fuse. I don't remember the model number, or where I saw it, unfortunately - sorry. But you may be seeing that.

2/3/2006 7:19 AM

R.G.

Re: Help! Marshall 4203 blowing fuses, not PT

My brain finally dredged up what may be an important bit of info for you.

I dimly remember that some Marshalls have the bias supply connected so that when the standby switch is turned to the sound-off position, the bias supply is turned off as well. When the standby switch is turned to the play position, the main B+ comes up faster than the bias supply, and so there is a short time when the tubes are unbiased with the heaters hot. This makes for a big slug of current that diminishes as the bias supply comes up. That kind of thing could definitely pop a non-slow-blow fuse.

I don't remember the model number, or where I saw it, unfortunately - sorry. But you may be seeing that.

Replies:

Carl Gigun This amp appears to work like that ... -- 2/3/2006 4:02 PM