MPS 2240 problem

alehed · Post by **alehed** » Wed Nov 19, 2014 8:04 am

I have a mps 2240 that i open up today to check the caps. I never tried it after i bought it so i didn't realised that i had a bad one.

So one of the "lines" in the board is burnt of as you can se in the picture and what i want to know is it possible to fix this with a little wire and what can be the reason it broke?

One of the pictures are not my amp but i put it there to make it easier to se were the damage is.

trickyricky · Post by **trickyricky** » Wed Nov 19, 2014 10:37 am

Too much current perhaps...is the trace open or just discolored.

alehed · Post by **alehed** » Wed Nov 19, 2014 11:22 am

its open.

trickyricky · Post by **trickyricky** » Wed Nov 19, 2014 11:54 am

If you solder a jumper make sure you power it up with a 5 amp fuse on the b+.

zeropoint0.5 · Post by **zeropoint0.5** » Wed Nov 19, 2014 12:57 pm

i had this one time in a ms275.......the powersupply of you're amp is probably fried.....

replace the 4 irfp044 fets and the gate resistors, and check out for other broken parts..

strip a FTP cable and use one of the 8 wires to replace the broken trace......

yes the 5A fuse is a must or it will happen again with the trace.....

when i had that, i powered that amp up on a 30A fuse with the blown traces as a result....

good luck with it.....

alehed · Post by **alehed** » Wed Nov 19, 2014 8:05 pm

Thanks guys. Can you point out the fets and the resistors in the picture it would save me a lot of time.

alehed · Post by **alehed** » Tue Apr 05, 2016 3:36 am

I try again. is there anyone here that can point out the gate resistors for me. Not that in to electronics but i think i can replace the broken parts if i know what parts to replace. Thanks

trickyricky · Post by **trickyricky** » Tue Apr 05, 2016 5:51 am

They are near the PWM IC.

Mr. Wild · Post by **Mr. Wild** » Tue Apr 05, 2016 6:02 am

R9 -R12 100ohm fusible resistors.

alehed · Post by **alehed** » Tue Apr 05, 2016 7:32 am

As i understand this is the resistors but they are 47ohm resistors if i´m not wrong here.

Thanks for all the help so far.

Mr. Wild · Post by **Mr. Wild** » Tue Apr 05, 2016 8:53 am

Use the same values as you have in there. The values must vary between different revisions of amps.

alehed · Post by **alehed** » Tue Apr 05, 2016 9:06 am

Is it possible to measure them were they sit or do i fooling my self. Did try and got about 47 ohm´s.
I know it´s cheap stuff but don´t want to mess with it if i don´t need to.

zeropoint0.5 · Post by **zeropoint0.5** » Wed Apr 06, 2016 8:49 am

alehed wrote:Is it possible to measure them were they sit or do i fooling my self. Did try and got about 47 ohm´s.
I know it´s cheap stuff but don´t want to mess with it if i don´t need to.

i checked the shematic of mps2240 for you and i can confirm they are 47ohm/0,25w metalfilm

hoping you're helped with this....

alehed · Post by **alehed** » Wed Apr 06, 2016 11:15 am

Have ordered the fets and the resistors. I hope i can fix this now.

Post by **Eric D** » Wed Apr 06, 2016 12:31 pm

If you remove the FETs, you can power on the amplifier, and measure the pins on the board where the FETs go, which connect to those resistors. With an o-scope you should see a square wave signal, with a DMM you should measure maybe 6V DC, and around 6V AC as well. The frequency is probably 30kHz. If you get figures anywhere close to these, you then will know the SG2525 PWM controller is functioning correctly. At that point I would put the FETs in, and then pull the rails fuses, and try to power it on. Again, use a small value fuse in case something else is still wrong. If you get both rails to come on, you can proceed.

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