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MA5000 failure


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#1 Renard

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Posted 20 February 2006 - 01:15 PM

Dear Sir,

I have a problem with one of my MA5000VZ amps.

When I turn on the unit with no speaker nor signal connected to the amp, all things turn on and off as normal. When I connect the speakers to the speaker terminals, the IOC light on one of the channels will turn on (no audio cables connected)!

When i connected audio cables (signal) to the amp (no speakers connected) , the moment I turn the volume, the IOC light will turn on, on the troubled channel.

The problem is with only one channel.

Can you elaborate where the problem might be, by the way none of the red lights inside the amp. will go on, so no problem here.


Thank you in advance.

Renard Hurtado

#2 DGlass

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Posted 22 February 2006 - 12:47 PM

IOC is an Input/Output Comparator circuit that is looking for any difference in signal greater than 0.05% other than amplitude. It is basically saying there is something on the output that shouldn't be there and the amp is going into protection. Not having it on a bench and looking at it ,however...... it would be very hard to say what exactly the issue is. It could be several things from a bad component on the main board to a bad output device.

I would recommend you get it in for service to either us or to a qualified Crown Authorized Factory Service Center.

#3 Renard

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Posted 23 February 2006 - 11:01 PM

[Hi,

Thanks for your reply.

Since yesterday this amp. started working Ok again, I really don`t know what happened. This week-end I will be using in during the Carnival parade, which means five to six hours none stop music, at full power. This same problem I noticed on an old Ma-2400 (8 years old), that I use only twice or three times a year. When i powered it up, it took some time for the ODEP (red lights) to come on. then i thought it was Ok, but when powering up the next day, it seemed like a relay or so on one of the channel was going crazy, because the IOC light started going on and off, and the ODEP light went out.  I opened up the amp. used an air compressor to blow it clean, and today when I turned it on, it was working normal again. This amp. will be in the parades to, let`s hope for the best.


Regards,

Renard Hurtado

#4 sidrambill

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Posted 29 June 2006 - 04:41 PM

QUOTE(Renard @ Feb 24 2006, 12:01 AM)
[Hi,

Thanks for your reply.

Since yesterday this amp. started working Ok again, I really don`t know what happened. This week-end I will be using in during the Carnival parade, which means five to six hours none stop music, at full power. This same problem I noticed on an old Ma-2400 (8 years old), that I use only twice or three times a year. When i powered it up, it took some time for the ODEP (red lights) to come on. then i thought it was Ok, but when powering up the next day, it seemed like a relay or so on one of the channel was going crazy, because the IOC light started going on and off, and the ODEP light went out.  I opened up the amp. used an air compressor to blow it clean, and today when I turned it on, it was working normal again. This amp. will be in the parades to, let`s hope for the best.


Regards,

Renard Hurtado
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#5 sidrambill

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Posted 29 June 2006 - 04:58 PM

QUOTE(Renard @ Feb 20 2006, 02:15 PM)
Dear Sir,

I have a problem with one of my MA5000VZ amps.

When I turn on the unit with no speaker nor signal connected to the amp, all things turn on and off as normal. When I connect the speakers to the speaker terminals, the IOC light on one of the channels will turn on (no audio cables connected)!

When i connected audio cables (signal) to the amp (no speakers connected) , the moment I turn the volume, the IOC light will turn on, on the troubled channel.

The problem is with only one channel.

Can you elaborate where the problem might be, by the way none of the red lights inside the amp. will go on, so no problem here.


Thank you in advance.

Renard Hurtado
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Renard, I'm having the same problem with a macrotech 1200. I do get a muddled signal on the bad channel and would like to know what your solution was/is. There should be someplace we can stick the probes on a meter to see what is supposed to be doing what. If it were a moving light I would know what to do but this audio thing seems to be all electronic with no moving parts other than a couple of relays and a fan. Thanks, Bill

#6 Jimraines

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Posted 23 March 2014 - 06:22 AM

I just had an ma5000vz fail it's only 15 years old I bought it bran new I'm no anywhere as tech smart as you guys are it's got the same problem I have been reading on the forums about.
Channel 1 ODEP light out & the IOC is bright green & it's got 2 red LEDs on that say channel 1 standby & channel 1 output mod fault I believe is what it says on the PC board.
I'm just going to send it to crown service it's $488 flat fee & shipping just to them.
I think that's probably my best option
I just wanted anybody here know that crown will still repair it & the price is reasonable

#7 joust

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Posted 24 March 2014 - 09:40 AM

Some precision : The MA series includes the MA600, MA1200, MA2400, MA3600VZ, MA5000/02VZ. The MA600/1200/2400 are very similar in construction, operation and general circuits. But, you cannot compare these three amps with the likes of the VZ amps (3600/5000/5002). Problems that appear similar are very different.
Unfortunately, Bill, I doubt that the solution found for the MA5K will be useful with the MA1200. What do you mean by 'muddled'? Not enough power? Frequency bandwidth? Gain? Distortion? Check cables? A lot of times, resoldering of power devices can help : I see a lot of broken solder connections on the devices leads.

Alain

#8 joust

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Posted 24 March 2014 - 09:48 AM

As I mentionned in my previous post, muddled sound could be caused by intermittent connections of o/p device leads. I've seen a lot of MA5Ks with cracked solder leads (MA1200!) on o/p modules devices. Remove the old solder and clean the solder spot. Add new solder to the connection. I recommend lead free solder (has a higher melting point than leaded solder). Push on the cards when soldering.
Note : If you are replacing the older solder with new, then perhaps it is time to refurbish the output devices : remove devices, clean devices and heatsink, and apply thin coat of thermal compound to both device and heatsink, reinstall and solder o/p devices.

Alain