uh, and i ******* up again, caps and rectifiers got ugly warm - dead?

[jan.didden]

now, i checked, and checked again, but this thing is still acting so wierd..

could it be that the cap is shot, and that there is contact to some extent inside it, why in the hell would it get hot otherwhise?

this thing is bugging me out..
the lm ic's seem fine though, getting warm, but nothing more than a lm3886 turning on for the first time is supposed to get..

BAH!!

thanks
marius

Marius,

Do this methodologically. Disconnect anything from the supply - GC, buffer, what have you. Then disconnect the two supplies from each other. Then recheck each separate supply (transformer sec, bridge, reservoir cap). See that you get 2 times a correct DC. If that works, connect the two supplies together and see if you get the three wires with +, 0, - voltage.

Next, measure the resistance on the buffer and GC between the supply pins and each of the pins to the GC and buffer ground (still no supply connected).
You should not get a very low value, a few k is OK. Note: if you have caps on the GC and buffer, they will charge when you measure resistance and it will LOOK as if the resistance starts at zero and then climbs up. That's OK, if in doubt let us know what you measure. If you measure something that looks like .6 or .7, reverse the meters on your resistance meter.

Then connect the buffer only, if possible, to the supply. See if that stays in one piece. If yes, check the DC out of the buffer. If (close to) zero, try to play some sound through the buffer.

Then to the GC, connect supply, check for DC out, should max be a few tens of mV. If OK, you're home free. If not, tough luck....

Jan Didden

 

[jan.didden]

Thats exactly, why CarlosFM was not joking: wear sunglasses the first time you try your amp!

Just in case of an exploding cap or chip, to protect your eyes!

Franz

Don't tell me you guys put the whole thing together and then turn it on?? That's daft!

Jan Didden

 

[carlosfm]

Don't tell me you guys put the whole thing together and then turn it on?? That's daft!

Jan Didden

My advice was for Marius and is the same for any beginner.
Actually I was joking, but I've seen many things happen with beginners, that in the end it's not such a joke.

I don't do that, because I have my methods of working, checking and measuring before powering everything on.

 

[demogorgon]

Jan!

thanks for the trubleshooting tips, i will be going over my amp asap afer my two weeks in algarve, portugal.

btw: carlos, how's the weather over there? should i bring shorts?

 

[carlosfm]

... i will be going over my amp asap afer my two weeks in algarve, portugal.

btw: carlos, how's the weather over there? should i bring shorts?

Wow!
As a Norwegian, you'll fry.
It's sunny here, and around (+) 20ºC.

Bring the shorts, or don't bring anything!

 

[ROVSING]

Oh no Rovsing, not again
Are you ever gonna learn that

Steenoe

Well....... i was not quite sure that it was wrong the first time, so offcourse i did it on purpose the second time, to doublecheck i'm sure you'll understand.......
Learning by doing i've learned it twice...
Am i on deep water now ???

 

[demogorgon]

Wow!
As a Norwegian, you'll fry.
It's sunny here, and around (+) 20ºC.

Bring the shorts, or don't bring anything!

And how is the Cola?
if i dont get my Coke WITH fizz, i get cranky..

and i'v heard your Coke dont have fizz..
so your mountain dew better have

 

[demogorgon]

OK, thank you all for your help and input, and it is with great pleasure i now can tell you that the amp is working.

so far so good, but i'm gonna let it burn in for some time first, before i make judgments.