Hi! I'm new to electronics diy, basically retired and since no one near me wants to fix my receivers, yep, they will receive the service they need...somehow. my immediate issue is with the marantz pm-94 and finding replacement mosfets. The factory ones are 2sk405/2sj115, which are long gone, and according to an article that I read, somewhere, the replacement for those are 2sk1530/2sj201, which are no longer available. I really love this amp and would love to find a great pair of replacement mosfets. Thank you all!
Tony
Tony
Hello!
Did you take a look on the 2SK1058 / 2SJ162?
Not a direct replacement, but they are similar in terms of voltage, current, power and capacitances.
Maybe it's worth a try.
Did you take a look on the 2SK1058 / 2SJ162?
Not a direct replacement, but they are similar in terms of voltage, current, power and capacitances.
Maybe it's worth a try.
use of those will require significant redesign! 2sk1058/2sj162 are lateral MOSFET with ~100mA tempco, relatively low threshold voltage, relatively low Gm and (this is the biggie) DIFFERENT PINOUT!!! 2sk1530/2sj201 family (there are other part numbers in the family with lower VDS max that might work for you) are best easiest replacement IF you can get them. There are members here that sell them - I would trust that before gambling on ebay.
Good luck - I feel your pain ....😖
It's really too bad all these good parts have been discontinued ....
Good luck - I feel your pain ....😖
It's really too bad all these good parts have been discontinued ....
Hey Ron! Thanks for the support!
After reading lots of comments/ advice to diy like myself, I found a tech advising a newbie to take a look at the datasheet of 1rfp240pbf-nd and 1rfp9240pbf-nd. I'm totally new to electronics, but reading datasheet has helped me somewhat.
I have to make a decision by the beginning of next month or so.
I'll look into your suggestion and see what I can come up with...and hope don't end up granading the amp.
I bought this amp, and two others to have the local tech rebuild them...one tech died last year and the other one retired...just my luck!
After reading lots of comments/ advice to diy like myself, I found a tech advising a newbie to take a look at the datasheet of 1rfp240pbf-nd and 1rfp9240pbf-nd. I'm totally new to electronics, but reading datasheet has helped me somewhat.
I have to make a decision by the beginning of next month or so.
I'll look into your suggestion and see what I can come up with...and hope don't end up granading the amp.
I bought this amp, and two others to have the local tech rebuild them...one tech died last year and the other one retired...just my luck!
Hi @Tony.g
OK! Look the details on the datasheets.
Also note what mlloyd1 mentioned that the Mosfet I pointed out has different pinout (I overlooked that, I'm sorry).
The Drain and the Source are reversed. It's better to find a Mosfet with same pinout so minimum mechanical changes are needed.
Normally mosfets have Gate-Drain-Source as pins 1-2-3, but the one I mentioned has Gate-Source-Drain which would need adaptations.
Read the datasheets, compare all the main values, the encapsulation (for mechanical compatibility) and pinout.
If you have doubts, post here so people can comment before you move forward.
In addition, when reparing amplifiers, always use some kind of current limitation in series with mains so you limit power if something is wrong.
Old popular solution is to insert a 60W bulb in series - once you check everything is working fine, than you can remove the limiter and connect directly to mains.
OK! Look the details on the datasheets.
Also note what mlloyd1 mentioned that the Mosfet I pointed out has different pinout (I overlooked that, I'm sorry).
The Drain and the Source are reversed. It's better to find a Mosfet with same pinout so minimum mechanical changes are needed.
Normally mosfets have Gate-Drain-Source as pins 1-2-3, but the one I mentioned has Gate-Source-Drain which would need adaptations.
Read the datasheets, compare all the main values, the encapsulation (for mechanical compatibility) and pinout.
If you have doubts, post here so people can comment before you move forward.
In addition, when reparing amplifiers, always use some kind of current limitation in series with mains so you limit power if something is wrong.
Old popular solution is to insert a 60W bulb in series - once you check everything is working fine, than you can remove the limiter and connect directly to mains.
Hi Ron!
Yeah, the original mosfets were 2sk405 and 2sj115, no longer available but I did bought a pair from aliexpress just to test and compare values. I also have a dim bulb set up.
I'm under no pressure since this is a hobie for me Ron. I'm waiting for the rest of the transistors on order and caps, and hopefully I'll be able to adjust the bias by june...it will be my first time...and yes, I do have an extinguisher next to my bench.
Yeah, the original mosfets were 2sk405 and 2sj115, no longer available but I did bought a pair from aliexpress just to test and compare values. I also have a dim bulb set up.
I'm under no pressure since this is a hobie for me Ron. I'm waiting for the rest of the transistors on order and caps, and hopefully I'll be able to adjust the bias by june...it will be my first time...and yes, I do have an extinguisher next to my bench.
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