ESP - P68 300W dont work ! help

[sajti]

for the first check i dont put the transistors on heatsink.....

This is not a good idea. The output device rated to 200W on heatsink, can dissipate 3-4W without heatsinks, so the bias current can kill them. Just put them to the heatsink!

Sajti

 

[rahkik]

WHEN i power on the amp. the resistance R13 & R14 OF 220 Ohm burn what can i do..
the o/p transister is not connected........


PLEASE HELP...

 

[TANDBERGEREN]

The reason is because the output transistors aren't present.

NEVER a good idea not to complete the cirquit before initial testing.

Also check the presence and polarity of the two diodes, D2 and D3, in addition to the presence and polarity of the two transistors Q5 and Q6

 

[amptech]

Hello to all,, there is plenty of helpful information being passed along to aid dj and his broken amplifier.. The safety lamp test on the primary of the mains power transformer would have lit nice and bright at switch on...

Looking at rods warning.. This amp should not be your first project..etc..

Most of us on here have being doing electronics half our lives so we can pass good advice to those that get stuck from time to time...
As out lined using limiting resistors to save blowing things up on powering new builds is a must...
Dj, you said something about 2 ohms subs? This amp is not designed for such Low speaker loads and will fail very fast...and the max supply rails is 70 plus and minus Dc.. You can test this amp on lower rails of say 20 volts..

Rod also states this amp needs fan cooling..
If possible upload a photo of your build so far..

Regards A..

 

[meanman1964]

I was wondering,D1 and D2 need to be connected to the same heatsink as Q4-5-6.Isn't it possible to use two BD139 trannies with the emiter and collector tight together to act as a diode to replace the two diodes,This way you can attach them to the sink in a nice way.

 

[amptech]

Mean man 1964, that is possible but you could clamp diodes with small shaped brackets or use a trim pot and mod the circuit the standard transistor sero and have better control over adjustment of the o/p stage.

 

[meanman1964]

Mean man 1964, that is possible but you could clamp diodes with small shaped brackets or use a trim pot and mod the circuit the standard transistor sero and have better control over adjustment of the o/p stage.

The reason for asking is I'm planning to make a new layout of this amp for my benifits.The thing you mean can you show this in the scheme or with a drawing?