M SERIES CHECKUP - DANGER TAKE A LOOK

dBincognito · Post by **dBincognito** » Fri Apr 24, 2009 5:56 am

OK....I will be pulling apart a M25 later on to see if it has the same problem..

2 M50's that I have opened up have the same exact problem, it leads me to believe that there could be many others as well.

Eric or Jim if you know about this or have anything to add that would be nice.....looking for these resistors right now. 26M ohm

I should have pics later today

Under the heatsink of both M50's.....right beyond the MOSFETS.....

On both M50's this whole section is shot....looks like it may get really hot under that heatsink ? Bad Location ?

1 of the M50's works no problems at all....didn't even know it had the problem until I opened it up for a comparison to the other 1 that I am repairing right now

Post by **Wakeup** » Fri Apr 24, 2009 6:40 am

Just curious....could you explain what the problem is?

Stryker · Post by **Stryker** » Fri Apr 24, 2009 6:53 am

NURSE!!!! get the defib.....

GX3 · Post by **GX3** » Fri Apr 24, 2009 7:02 am

NURSE!!!! get the defib.....

CLEAR

Stryker · Post by **Stryker** » Fri Apr 24, 2009 7:18 am

shaheen · Post by **shaheen** » Fri Apr 24, 2009 7:39 am

I tihnk Eric mentioned it somewhere, he did a mod which basically moved the resistors off the board, extended the leads and got it to press up against the heat sink for better heat transfer

marko · Post by **marko** » Fri Apr 24, 2009 7:41 am

i'm sure Eric did a mini tutorial about a little custom mod you can do to make the resistors cooler by mounting them closer to the sink with thermal paste too, i could be wrong and maybe someone can remember the thread and where it is?

dBincognito · Post by **dBincognito** » Fri Apr 24, 2009 8:53 am

Pictures coming soon....dealing with something else right at the moment

Wakeup

Just curious....could you explain what the problem is?

The whole section burnt up......I haven't dove into it yet

andy600rr · Post by **andy600rr** » Sat Apr 25, 2009 6:02 pm

marko wrote:i'm sure Eric did a mini tutorial about a little custom mod you can do to make the resistors cooler by mounting them closer to the sink with thermal paste too, i could be wrong and maybe someone can remember the thread and where it is?

I think its somewhere in here.....

http://phoenixphorum.com/m50-and-m44-advice-vt4213.html

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:09 pm

andy600rr wrote:
marko wrote:i'm sure Eric did a mini tutorial about a little custom mod you can do to make the resistors cooler by mounting them closer to the sink with thermal paste too, i could be wrong and maybe someone can remember the thread and where it is?
I think its somewhere in here.....

http://phoenixphorum.com/m50-and-m44-advice-vt4213.html

Nope, not even pictured or talked about in that thread

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:14 pm

I am talking about parts located under the heatsink....I didn't even see a heatsink removed in that thread

andy600rr · Post by **andy600rr** » Sat Apr 25, 2009 6:19 pm

Ahh crap, thought it was there.

There is def a pic in this thread although it's not the one I was looking for

http://phoenixphorum.com/outlaw-in-dist ... ight=paste

I'll keep searching though.

<edit> I've had a look and can't seem to find the thread I was thinking of.

In simple terms, the resistors under the heatsink were replaced, and instead of being set down on the board, the leads were left slightly longer so that the resistors would rest on the base of the heatsink. Smear some heatsink compound on the resistors to help conduct the heat through to the sink and you're good to go.

Hope this makes sense.

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:24 pm

andy600rr wrote:Ahh crap, thought it was there.

There is def a pic in this thread although it's not the one I was looking for

http://phoenixphorum.com/outlaw-in-dist ... ight=paste

I'll keep searching though.

BINGO....where Eric D says this

I implemented my new resistors against the heat sink so they don’t cook themselves method

That is exactly what I am talking about....that is what needs to be done

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:26 pm

You couldn't ask for a more perfect picture either.....prynrd's whole section is burnt up there.....this mod should be in the How To Section....very important if you ask me....

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:31 pm

20 ohm 5% resistors needed......

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 6:33 pm

Still think that mod should be in the How To section....as in How To save your M amp from burning up

Post by **Rold Gold** » Sat Apr 25, 2009 10:25 pm

Charging...............

dBincognito · Post by **dBincognito** » Sat Apr 25, 2009 10:28 pm

FuzzyHoNutz wrote:Charging...............

Post by **Eric D** » Sun Apr 26, 2009 6:09 am

Is this what you need?

dBincognito · Post by **dBincognito** » Sun Apr 26, 2009 6:12 am

Yes sir....I need to get those resistors to do this mod for him....can you direct me to the correct part...or just give me the power rating please

dBincognito · Post by **dBincognito** » Sun Apr 26, 2009 6:21 am

It looks like you used these ?

http://search.digikey.com/scripts/DkSea ... 20W-1TR-ND

dBincognito · Post by **dBincognito** » Sun Apr 26, 2009 6:25 am

You see that whole section prynrd...all 4 of those resistors on your M50 are fried and so are the 4 litte yellow capacitors

Post by **Eric D** » Sun Apr 26, 2009 6:34 am

I think I used Yago 1W resistors.

dBincognito · Post by **dBincognito** » Sun Apr 26, 2009 6:35 am

Eric D wrote:I think I used Yago 1W resistors.

Thank you kindly sir....I was looking at the Yago's last night...didn't want to go through with a order until I heard from you...do all of the M amps have this problem ? Or is it more common with the M50's

dBincognito · Post by **dBincognito** » Sun Apr 26, 2009 8:11 am

This looks to be them

http://search.digikey.com/scripts/DkSea ... e=20W-1-ND

Edit : Confirmed...pryrnd you can see the cost...told you, cheap