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Electronics => Repair => Topic started by: mjrpainless on March 09, 2018, 02:44:53 am

Title: Replacement transistor for a PSB subwoofer
Post by: mjrpainless on March 09, 2018, 02:44:53 am
Hey all, hope that someone might be able to point me in the right direction.

I have an amplifier board for a subwoofer that I am trying to repair. I have narrowed it down to a bad transistor. But am unable to find a replacement tx.

the sub is a PSB Century Subsonic 2i with an Indigo MAIN 600049 REV 7 board. The transistor that is blown is a HARRIS IRF9543.

I was able to find a replacement samsung i believe it was, but they are only rated up to -60V (this is from memory so if its wrong I'm sorry)

Thanks all
Title: Re: Replacement transistor for a PSB subwoofer
Post by: Kleinstein on March 09, 2018, 09:06:05 am
Is this a linear amplifier with a large heat sink, or a class D type with a choke ?

The required voltage rating depends on the actual supply used. Especially linear MOSFET amplifiers tend to use higher voltage MOSFETs because of the often better SOA and not because they need the high voltage. So the voltage rating might not matter. However for linear use the SOA does matter and here different manufacturers might differ.

If in doubt, there is a 100 V rated  IRF9542.
Title: Re: Replacement transistor for a PSB subwoofer
Post by: Rog520 on March 09, 2018, 04:26:34 pm
A couple of sources pop up on Google:

Newegg, through a third party Chinese seller:
https://www.newegg.com/Product/Product.aspx?Item=2A3-0029-09K92 (https://www.newegg.com/Product/Product.aspx?Item=2A3-0029-09K92)

HB Electronics, out of California:
http://www.hbelects.com/product-6117/IRF9543 (http://www.hbelects.com/product-6117/IRF9543)

I have no experience with either one of them. Rochester also has them available, at a steep MOQ.

Title: Re: Replacement transistor for a PSB subwoofer
Post by: mjrpainless on March 09, 2018, 11:01:43 pm
Thanks Rog520, i was able to find the ones on the hdelects.com, but was unable to order from them. It wouldnt let me put anything in the shopping basket.

and i didn't seen the ones that were on Newegg. so i made an order, Thanks for the help!