M50 Shutting Off and with No Protect
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M50 Shutting Off and with No Protect
I bought an M50 the other day that is in pretty good shape cosmetically. The PO said that nothing had been replaced and he didn't want to deal with fixing it. I hooked it up and it turned on fine. The problem comes when I adjust the gain up (past 30%) the amp just turns off. The green light just fades out with no protect light at all. I am going to replace the caps but wanted to see if I need to check anything else. Sorry for the low amount of details but those are the ones I have. Thanks in advance!
Re: M50 Shutting Off and with No Protect
Id recap it before it sets itself on fire.
Sent from my SM-G960U using Tapatalkwesleyb420 wrote:I bought an M50 the other day that is in pretty good shape cosmetically. The PO said that nothing had been replaced and he didn't want to deal with fixing it. I hooked it up and it turned on fine. The problem comes when I adjust the gain up (past 30%) the amp just turns off. The green light just fades out with no protect light at all. I am going to replace the caps but wanted to see if I need to check anything else. Sorry for the low amount of details but those are the ones I have. Thanks in advance!
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- Joined: Mon Jun 11, 2018 10:13 am
Re: M50 Shutting Off and with No Protect
I clearly stated that the caps are getting replaced. I took the caps off and not a lot of leaky ones (1). What would cause the amp to just cut out?
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Re: M50 Shutting Off and with No Protect
Pics below
![Image](https://i.imgur.com/2dgOgdvb.jpg)
https://i.imgur.com/2dgOgdv.jpg
![Image](https://i.imgur.com/2ef21CNb.jpg)
https://i.imgur.com/2ef21CN.jpg
![Image](https://i.imgur.com/boNhL26b.jpg)
https://imgur.com/boNhL26
![Image](https://i.imgur.com/2dgOgdvb.jpg)
https://i.imgur.com/2dgOgdv.jpg
![Image](https://i.imgur.com/2ef21CNb.jpg)
https://i.imgur.com/2ef21CN.jpg
![Image](https://i.imgur.com/boNhL26b.jpg)
https://imgur.com/boNhL26
Last edited by wesleyb420 on Thu Aug 09, 2018 9:53 am, edited 1 time in total.
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Re: M50 Shutting Off and with No Protect
Hello
the power supply fets (IRFZ44) and the 2 diode (SF163) are not bolted to the heatsink. If you didn't take out the screws yourself look no further...
the power supply fets (IRFZ44) and the 2 diode (SF163) are not bolted to the heatsink. If you didn't take out the screws yourself look no further...
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Re: M50 Shutting Off and with No Protect
you also need to change the rail caps...
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Re: M50 Shutting Off and with No Protect
I took the screws out...should I replace the caps?
Re: M50 Shutting Off and with No Protect
caps def need to go.......
what else can I say I am a grumpy asshole most of the time.
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Re: M50 Shutting Off and with No Protect
Are we speaking about the rail caps? The other ones will be here tomorrow.
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Re: M50 Shutting Off and with No Protect
Does the shrink wrap on the rail caps indicate something? Got hot and slid down?
Re: M50 Shutting Off and with No Protect
means the caps are bad.
what else can I say I am a grumpy asshole most of the time.
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Re: M50 Shutting Off and with No Protect
Ok, so one rail cap tested bad. I took them out but I lost a solder pad in the process. From what I can tell, the solder pad does not have a trace on the bottom side. Is that pad just to hold it and the actual trace is on top? Can I just use the superglue method and re-attach it?
thanks for the help on this and please overlook the excess solder...I have not used the solderwick yet, just the sucker.
thanks for the help on this and please overlook the excess solder...I have not used the solderwick yet, just the sucker.
Re: M50 Shutting Off and with No Protect
If you navigate to the how to section of these forums, there is a very good tutorial on the repair process, and a few posts under the stickys on how to repair the through holes. If i recall correctly pg used a 4 layer board? I could be wrong there. But broken is VIAs generally bad if not repaired...
Sent from my SM-G960U using Tapatalk
Sent from my SM-G960U using Tapatalk
Re: M50 Shutting Off and with No Protect
there is a few ways to repair it. Its not hard to lift a via and loose it. I finally got a repair kit to make it easier and better looking but it was not cheap
what else can I say I am a grumpy asshole most of the time.
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Re: M50 Shutting Off and with No Protect
I did end up finding that after scrolling.
Can anyone verify that this is just a two-layer board, not a four-layer that someone mentioned above? I am not seeing any traces between the layers, just on the bottom and top.
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Re: M50 Shutting Off and with No Protect
it's a two-layer board
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Re: M50 Shutting Off and with No Protect
Thank you, everyone, for the assist...everything works!!!