Gallien-Krueger MB Protection Circuit Problem

R

REB

Apr 6, 2007
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#1
I'm sure there is an answer here somewhere but I'm suffering form information overload.

Regarding the red ring of death protection circuit issue, I understand that this indicates a icepower power amp problem, but is there typically an external (something other than the power amp itself) cause to the power amp failing? Is there usually a pre-amp, speaker, etc. problem that has to be addressed first?

I don't want to buy another power amp just to have it fail as well.
 
#4
eriky4003 said:
You may want to give the hive more info? MB amp only or combo? I had to have my power amp module replaced last year after 10-11 yrs of use (ICEpower just to be topical based on recent threads).
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Oops, sorry. It's a MB110

Actually, now it's giving me a blue ring but still no sound through the speaker or headphone jack.
 
#5
REB said:
Oops, sorry. It's a MB110

Actually, now it's giving me a blue ring but still no sound through the speaker or headphone jack.
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I think you will discover that there is more going on than the module. This is why I recommend a QUALIFIED, factory authorized service center to properly diagnose and repair your amp.
 
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#6
agedhorse said:
I think you will discover that there is more going on than the module. This is why I recommend a QUALIFIED, factory authorized service center to properly diagnose and repair your amp.
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Thanks for the help, I do appreciate it. Since it was free to me I thought I might try to investigate the issue some myself and learn a little about ICs but I was hoping there is a common thread with these GK MB amps that could narrow it down. But I admit I know enough to be dangerous so I might just sell it as is. The previous owner said he took it to a service tech who just said it needed a power amp so I was hoping it would be a fun experiment.
 
#7
REB said:
Thanks for the help, I do appreciate it. Since it was free to me I thought I might try to investigate the issue some myself and learn a little about ICs but I was hoping there is a common thread with these GK MB amps that could narrow it down. But I admit I know enough to be dangerous so I might just sell it as is. The previous owner said he took it to a service tech who just said it needed a power amp so I was hoping it would be a fun experiment.
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Not to suggest anything about the previous owner, but IME it's almost never a good sign when someone is giving something away for free and tells me all needs is a power switch, or a fuse, or an alternator, or a starter, or whatever. Those stories never seem to end well for me...although YMMV (assuming you can get the car started). :)
 
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#8
What were you hoping to learn about IC's from a class D amp and SMPS? I might be able to point you to a good book or two on the subject that you could actually learn something from.

Just because a tech says that it's just a module means nothing. I have analyzed service center defective parts returns for several brands that I was involved with over the years and the one common theme is gross misdiagnosis of problems related to class D. Well over 50% of all returned modules claiming defective go through a full battery of tests and end up meeting all the factory specs. Other manufacturers that I deal with see the same thing, the less qualified the tech the greater the number of diagnosis mistakes (or at some point they aren't mistakes but bad guesses).
 
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#9
Al Kraft said:
Not to suggest anything about the previous owner, but IME it's almost never a good sign when someone is giving something away for free and tells me all needs is a power switch or a fuse, or an alternator, or a starter, or whatever. Those stories never seem to end well for me...although YMMV (assuming you can get the car started). :)
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Exactly, this is the norm and not the exception IME.
 
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#11
B-string said:
Other than a shorted speaker (rare) there is nothing anyone should attempt ion the ICEPower module without extensive training. The red light is a worry, but is clearing to the blue operate is confusing. Unknown what may have been left from a previous "repair" attempt.
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Attempting a repair on an ICEPower module also voids the safety certification that's part of the module.
 
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#12
I had a similar problem a few years ago with my first-generation G-K MB 115 where I was getting the "red ring of death" then when I cut it off and cut it back on, it would sometimes clear and work normally again for 20-30 minutes, then would cut out again. As it was out of warranty, I still called G-K and told them what it was doing. They told me the problem appeared to be the ICEPower power amp module, and referred me to Parts Express with the part number for the new module. Since it only cost around $120 and was a simple swap out, I figured it was worth a try even with my fairly basic electrical skills. I replaced it and haven't had any problems since.

I wouldn't have attempted any repair to the ICEPower module that wasn't a total swap out. Give G-K a call before you try anything yourself.
 
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#16
B-string said:
Other than a shorted speaker (rare) there is nothing anyone should attempt ion the ICEPower module without extensive training. The red light is a worry, but is clearing to the blue operate is confusing. Unknown what may have been left from a previous "repair" attempt.
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Good advice but I'm not trying to repair the icepower module. I want to replace it but I'm trying to make sure that there isn't an issue with the pre-amp or some other component and destroy a new power module and waste $150.
 
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#17
REB said:
Good advice but I'm not trying to repair the icepower module. I want to replace it but I'm trying to make sure that there isn't an issue with the pre-amp or some other component and destroy a new power module and waste $150.
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I don't have that schematic on hand in my cache so beyond a DC offset from the preamp output and exceeding secondary supply current (if spec available from ICEPower) which you need a Lab power supply for preamp testing I'm not sure what else you could look for.
 
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