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Old 28th May 2003, 08:08 PM   #1
elizard is offline elizard  Canada
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Default flash .. bang .. oily liquid .. no music!

well ..
i got my transformer today

now .. before i start complainin
i used a transformer with a single secondary and got the gc to work

onto my story
hook it up like i thought i should ..
seems to work .. no smoke yet
hooked up the gainclones to the PS .. a cap gets hot .. some smoke and a small poof - i turn it off
nothing exploded .. i think 2 wires touched .. *whew*

checked the voltages put out by the power supply .. both are positive
not good!

try 2 .. 3 .. 4 .. 5 different ways to hook it up and check the bridge
ok .. i got a +23 and a -23, but on what seemed to be the wrong terminals, and get +23 and +23 or -23 and -23

tried one combo which seemed to work .. but i got +23V on the speaker outs
ouch .. no speaker connected to it thankfully!!!
the other GC gave +5V .. odd

switch bridge around .. get +23 on one, -23 on another .. good so far!

hook up the gainclone .. no smoke right away
so i turn around to grab the multimeter .. something buzzed
i turn around to turn it off right away, but just as i reach for the switch a poof, and some smoke ..
and one of my GC's is swimming in oily liquid from the capacitor that blew
so .. i curse a little and give it up for the day

i also wish i had just bought a stereo .. but once i'm rested again, i'll change my mind and troubleshoot this
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Old 28th May 2003, 08:18 PM   #2
tiroth is offline tiroth  United States
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Your ground is floating all over the place. That's why you can't use a single secondary.
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Old 28th May 2003, 08:21 PM   #3
Bricolo is offline Bricolo  France
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how did you build a GC with a single secondary trafo?

floating ground? (bad, bad, bad!)
single wave rectifier?
other?
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Old 28th May 2003, 08:23 PM   #4
elizard is offline elizard  Canada
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i guess i didn't make myself clear, again ..

i USED to use a trafo with a single secondary, and it worked perfect (for testing purposes of course!)

today i got my toroid .. 2x22V secondaries ..
that's what i used when i blew it
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Old 28th May 2003, 08:25 PM   #5
Bricolo is offline Bricolo  France
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I also blew up a cap one time

on the negative supply, make sure that the cap's - is connected to V- and not to ground
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Old 28th May 2003, 08:31 PM   #6
elizard is offline elizard  Canada
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i'm leaving it until later today, or tomorrow

the cap stinks when it blows up .. the stuff that comes out of it
or smell unpleasant actually .. and strange, yet familiar for some reason
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Old 28th May 2003, 08:38 PM   #7
karma is offline karma  Canada
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lets just hope your LM3875T LM3875TF. LM3875 LM1875 one
of em is not fried

yes cap's do stink i blew allot up as a teen

wow big storm coming
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Old 29th May 2003, 12:10 AM   #8
elizard is offline elizard  Canada
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i think one MIGHT be fried .. but no confirmation as of yet, i just woke up from my nap
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Old 29th May 2003, 01:05 AM   #9
elizard is offline elizard  Canada
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well ..
i fixed the voltages
now i get + on the right side, and - on the right side .. (it was good the first time!!!)

plug in the gc .. 2.5V on the speaker terminals
change the plug for the PS .. .25mV .. not TOO bad
plug in a crap-speaker .. nothing but a soft hum when there's input, and no hum when there's no input

check .. everything seems to be right
this might be the GC i saw smoke come out of earlier (not the cap related one)

now i gotta eat.. i'm starving
had next to nothing the whole day ..

then i'll replace the cap in the other GC and see if it works .. keep ya up to date
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Old 29th May 2003, 01:38 AM   #10
elizard is offline elizard  Canada
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well .. now i know somethings wrong

i replaced the cap in the 2nd gc ..
power up ..
fire!

as i blow out the fire and shut the power off .. scared the crap out of me since there's so much flammable stuff around

pin #1 was burned off completely .. and now is detached from the op-amp
the op-amp is black .. so i'm going to assume its fried

so .. which means i need 2 new lm3875's ..
damn

maybe i'll order tomorrow .. maybe ..
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