DJSlyfox

Macrotech 12000i/9000i overheating problems, ready light off

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DJSlyfox    0

Hi i currently own 8 macrotech 12000i amps as well as 8 9000i. The problem im having is one of the 12000i amplifiers the ready light isnt coming on. I assume its due to heat since this particular amp was in such environment. Is there a way to troubleshoot this problem? I have read that it may be the thermistor at fault. Also, most of my amplifier fans are racing off really loud after about 10minutes into turning them on. Im worried these may overheat on a gig and go into "standby" just as one of my current 12000is. Thanks in advance

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dakos    0

What you are describing are two different things, the fact that the fans are "racing off" as you call it, sound like normal behavior of the itech/mai amps due to their topology, if you have low signal level going into the amp, once you crack open the knobs the amps heat dissipation actually goes down and the fans relax.

The thermistor problem makes the fans race into full speed, you can't ignore the screaming sound comming out of them.

As for the amps ready light not coming on, I'll let my friend Alain elaborate.

Avi

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dakos    0

If the fans are going into full speed then something is wrong but there are many reasons for the fans to be racing off other than the thermistors so lets not assume anything before we actually know what's going on.

But... On your amps, due to their topology, if you lower the signal (lower the volume), the fans will start to work and make the noise you're describing, THIS IS NORMAL AMP BEHAVIOR!!

Avi

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joust    0

As Avi mentionned you may have different issues. I doubt you have a 'fan' issue: the airplane taking off syndrome comes about even without any signal. Also, it may happen more often in humid environments. Heat issues include dried out foam at the t-sens sensor (in older units), output devices not clamped properly, poor ventilation, o/p devices refurb necessary, solder connection of the BCA coils, etc.

WARNING: HIGH VOLTAGE INSIDE!

Make sure that all high voltages are discharged before any manipulations inside the amp.

As for the display's Ready light not coming on, this is 'swap module' time! Do the cards' Ready lights come on? If yes, then it may be possible that the Front End cards are OK.

Verify and measure carefully the output devices for shorts or open device.

[Can I make a suggestion to all you techs working on this type of equipment? I made a small capacitor discharger with a few PTC (positive temperature coefficient) devices. These are the blue, circular resitors that you find in a lot of sample mode power supplies. Usually, they're 6 ohms devices, cold. I solder four of these devices in series (24 ohms total), set these to a banana plug, and set it on my voltmeter (set to DCv). You use the voltmeter to view discharge rate.]

Note: Before swapping cards, identify the cards for their proper channel.

Start off by swapping Front End cards and power up: Do the Ready light change side? If yes, then it may be a faulty Front End card. If no, power off and discharge.

Carefully, swap gate drive cards; Do the Ready light change side? If yes, then it may be a faulty gate drive card. If not, power off and discharge.

Though, since you already have a few units, why not swap whole modules to locate and divide the troubleshooting task?

Alain

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DJSlyfox    0

i powered on the amplifier today and the ready light came on on its own without me making any changes at all. however this is only this amplifier the fan races off, reallyy loud compared to the other amplifiers, as soon as its powered on without signal or load. Is anyone aware of this problem? I know for sure the problem with the ready light not turning on was due to overheating. But now its turning on with a loud fan blowing cool air. I tried the amplifier with signal and load and it works as normal however im sure the 'surging' behaviour of the fan is a fault/ a setting that needs to be adjusted.

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joust    0

It may be possible that the 'fans turning on like an airplane' is due to a faulty thermister in the SMPS circuit. It may be detecting faulty thermal readings. Issue may happen in a humid environment or venue. Please get in contact or return the amp to an authorized Crown service center to correct the issue.

Alain

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