BA-3K POOF & back under the hood again....

And we're BACK... 49 bucks to fix....Burning in with a little David Bowie !
 

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A bit of a scare, Sunday night I had my son HEFT the BA back in the stand.. MONDAY AM I had a new audio book and was doing a front panel polish job on the dining room table.. so I fired up the BIG SYSTEM.. and that amp did not fire up at all.. ( 10 minute freak out later ) I used SCIENCE.. and my son had not plugged the amp in ....PHEW !
 
Been a LONG time since I last posted, many things have happened like RETIREMENT ! YEAH !!!
So my current system has 2 BA-3k's , each running mono, driving Westlake BBS-M 15's fed by the 3k Pre I did here MANY MANY moons ago.. The other day ( post household mishap in the plumbing dept ) I thought it would be nice to fire up the main system.... the right amp went CLICK and the nuttin.... The main fuse blew.
I had an 8 amp in there and it called for a 10 A...... New fuse in CLICK smoke POOF..... GRRRRRRRRR.
So off to the bench it went. I had been working on a Pioneer Spec 2 ( japan version M-77 100 volt ) . So that was not completed but stable enough to run... and we had tunes again. So with the fuse change I took out the 2 4 ohm inrush resistors, the left driver & 3 of the 6 output transistors. I THOUGHT I had an excess of OE output transistors.. but the gains of the devices are 80 to 125.. where the ones in the good right channel and the 3 that survived in the left are in the high 30's to mid 40's..So right now I have the protection board repaired, both the drivers working and the right main block working. I placed the Digikey order today for more MJ transistors.

Hope all is well with you guys.....
Pix to follow

Mike AKA VIGMAN ~

Apologies for bumping an old thread, but I have been going over all BA-3000 related threads in preparation for working on my recently acquired unit. When your amp went poof, had it been refurbed previously? I'm wondering if you were able to determine the cause of the random failure and what might be done to prevent this? Or is it just a matter of old amp, many old parts, one day something is bound to give up?

Thanks!

AW
 
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