ESP - P68 300W dont work ! help

[Dj BASS AMP]

Hii all .... my problam :

I build the amp ... i connect all the parts right ! like the pic !!!

now.... that i turn the power on.... the "R7" and "Q8" start to hot.... (the LED "D1" dont work.....) and the fuse blow...

i put a new fuse....

and... i deconnect the base of "Q5" and "Q6"....

turn on the power.....( the LED "D1" still dont work.....) and the fuse dont blow but now the "Q2" start to hot.... but slowle.....

i reconnect the the base of "Q5" to secend ! and the fuse blow again......

what my problam....... ?

***** and i connect to 35V +/- no to 56V +/- it is matter?

[jean-paul]

Maybe a stupid question but did you connect the LED right ??

[sajti]

Hi DJ,

first, keep the base of Q5, and Q6 disconnected. Check the polarity of the LED, and check the connection or Q1, and R8. You can remove Q1, too, and if the LED works, there was problem with Q1.
So the first step to get some light from the D1, and don't care with other parts of the amplifier. Until the D1 doesn't work, Your amplifier will out of order!

Sajti

[Dj BASS AMP]

hiii............

i connect the led inverted....... now i change that.....

so i power on........ the led works and the Q1-3 and R7 dont hot ani more.... (the base of "Q5" and "Q6"still deconnect...)

and if i connect the base of "Q5" for secend it is make short in the power.....

[jean-paul]

So you found the error. Now try to explain what transistors could be faulty because of the error.

[Rudy]

try to leave D2 out off the corcuit, dont leave it open but take a wire and shorten him.

This aint good but would solve the problem with shorten the voltage rails, iff the problem still remeans ... dunno, probebly wrong connections, and maybe intresting to post all the voltages when the power transistors ( q5 and Q6 ) or disconnected.

Greetz

[millwood]

I would suggest double or triple checking the connection.

[Dj BASS AMP]

how i check if the NPN and the PNP transistors if they "O.K" with multimeter..?

[jean-paul]

Use Google:

http://ourworld.compuserve.com/homep...tt/elect56.htm

http://www.elexp.com/t_test.htm

http://www.eatel.net/~amptech/elecdisc/ampfail.htm

Tamir, I really don't want to **** you off but I think you should do a basic course Electronics so that you'll know what you're doing. Faults ( even dangerous ones ) are easily made when basic skills are not adequate. But as an assuring remark I can tell I began the same way, it only takes more time and a lot more errors

As a second advise I can recommend buying Rod Elliotts PCB. They are very cheap and good quality. The risk of connecting LED and transistors wrong will be lower AND it looks better. If you buy boards from Rod you'll get access to his secured webpages where you'll find more information on the project including helpful tips.

[Netlist]

Originally posted by jean-paul

As a second advise I can recommend buying Rod Elliotts PCB. They are very cheap and good quality. The risk of connecting LED and transistors wrong will be a lot lower AND it looks better.

Jean-paul, I think it's difficult for DJ to obtain the PCB from Rod via Internet.
He mentioned that somewhere in an earlier post.

DJ, the link for measuring transistors has been given to you in the past. You should bookmark that site as well as the sites jean-paul gives you. This is very important and good info.

/Hugo - thanks I live in Belgium, everything is possible here. (Well almost)