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[Tim Perry]

Have you deterimed what's causing the 5A fuse to take a dump?

Scott, I have been studying the schematic. When doing the repair i was working from small paper printouts. I was primarily interested at the time in finding out the value of the burnt resistors. 

The internal fuse is 1/2 V-bulk.  This goes to the low side of the power transformer (T601)  it is 3A on the schematic.  It's being driven by an oscillator at what I think is 340 volts p-p.

The biggest discovery is that when the unit is operating at 120 volt line current this fuse (F1) is connected directly (through an RF filter) to the AC mains. (note: the schematic uses a non standard symbol for the switch here making it difficult to interpret)

This realization makes it more likely that a power line spike or surge could have been the problem.

When operating on 240 VAC the bulk DC supply is a tansformerless bridge rectifier. 
When switched to 120 VAC the Vbulk is configured as a voltage doubler.

The amplifier section is a bridged output type.

[David Morison]

Slight topic swerve but this got me to thinking that as far as I know no manufacturer at the consumer level that makes powered speakers provides an equivalent turn-key, non-powered system... or does someone? Of course d&b and others have such systems but they are obviously far out of reach of the average club guys.

Hi VOiD,
Closest I can think of is from your namesake company here in the UK - they don't actually do powered cabs but do a couple of turn key systems priced vaguely near the upper end of MI - Basys and Viper.
Cheers,
David.

[Michael Martin]

Hi Keith!
I'm a newbie on this forum as well, but I do have a set of suggestions for you (if you haven't already bought your equipment).
1) Buy quality. If you initially settle for less expensive gear, you'll be disappointed and end up replacing it soon.
2) Buy QUALITY...oops, wait, I already said that.
Several posts here have some great suggestions, and while I agree with using a passive speaker system (because you can use a MUCH better outboard amp), the active systems are good if you have enough of them. My son plays metal as well, and I am aware of the demands on a PA for a metal band...it HAS to be bullet proof and loud.
I play in a local classic rock band, and we use JBL SRX series subs and mains, with all Crest CA series amps. They are HEAVY, but some of the best touring amps on the market. Since these are passive, we use a DBX Driverack+ for complete digital speaker management. It isn't an inexpensive rig, but it sounds great and the Driverack allows it to sound consistent from venue to venue.
I'm not suggesting this rig is perfect for you...just making the point that if you buy cheap at first, it may come back to bite you.

Best of luck...

Michael

[TJ (Tom) Cornish]

Hi Keith!
I'm a newbie on this forum as well, but I do have a set of suggestions for you (if you haven't already bought your equipment).
1) Buy quality. If you initially settle for less expensive gear, you'll be disappointed and end up replacing it soon.
2) Buy QUALITY...oops, wait, I already said that.
Several posts here have some great suggestions, and while I agree with using a passive speaker system (because you can use a MUCH better outboard amp), the active systems are good if you have enough of them. My son plays metal as well, and I am aware of the demands on a PA for a metal band...it HAS to be bullet proof and loud.
I play in a local classic rock band, and we use JBL SRX series subs and mains, with all Crest CA series amps. They are HEAVY, but some of the best touring amps on the market. Since these are passive, we use a DBX Driverack+ for complete digital speaker management. It isn't an inexpensive rig, but it sounds great and the Driverack allows it to sound consistent from venue to venue.
I'm not suggesting this rig is perfect for you...just making the point that if you buy cheap at first, it may come back to bite you.

Best of luck...

Michael

Michael - you need to change your username to be your full name per forum rules.

[Michael Martin]

Done...thanks.

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