Punch 250 repair help

[cajundude]

I have a punch 250a2 with one channel that is blown. On of the transistors burnt up. I called the local electronic supply house and they tell me the transistor is obsolete. I am looking for a substitute if anyone can help.
the transistor number is MTP75N05HD.
thanks in advance

[Perry Babin]

The IRF3205 is a good replacement. What is the value of the gate resistors?

[cajundude]

I don't have a schematic, which resistor are you speaking of?

[Perry Babin]

R19 and R20.

Email me if you want the schematic diagram.

babin_perry@yahoo.com

[lithoc]

Dear All,

I've a Punch 250M with 6 X MTP50N06. 3 of them blown/burned.

Can this be replace with FQP85N06 ?

I planned to replace 6 of them.

It also have 4 X 2200uf 16v, which I'm planning to replace as well with 3300uf 25v.

Just want to know if there's advantage to replace this parts?

Will it give more power ?

Updates: I notice my MMBT3904/06 also burned.
2 have marking 1A and 2A. 2 more just FUBAR.




Thank you

[1moreamp]

the transformer design and PWM controller sets power levels, so your most likely just beefing up the supply and will only gain Durability with little to no power gain.
Adding cap value like you are at the 12 volt side will only assure that the supply does not share its electronic noise with the rest of the world around you. And not much else.

Boosting amps to red line there power output is not a wise thing to do. And you should understand that your actually removing all headroom and safe operating area out of the amp design. If you need more power I suggest that you just buy a bigger amp and turn it down if its too large for the rest of your system. PPI600 says this in his posts, " you can always turn it down" Make s a lot of sense to many....

[lithoc]

Thanks 1moreamp,

The reason I wanted to replace MTP50N06 to FQP85N06 is that FQP85N06 lower max RθJC 0.94.

The other reason is, it's easily available in my country.

[cajundude]

the resistor is r-19 i will email you my email
thanks