ITech 12000HD issues

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#1 Kasey

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Posted 30 July 2014 - 08:40 PM

I bought an itech 12000hd from a friend of mine and i only realized it had a problem when I played it for about 6 hours continuously. After the time, it just started playing very softly. I increased the input signal ,but it still played softly. I realized the fans were on hard, like an airplane. But the amp was cold. When I pulled up the temperature display screen, here we're the readings:
Ch1 38, Ch2 39, and PS 80. I tried resetting it but no change.

I left the amp alone for around a week, and then decided to test it again. On powering up I saw the following readings:
Ch1 32 Ch 33 PS 51.
I just left the amp on with no signal or load connected for around an hour and here were the readings
Ch1 25 CH2 26 PS 72
This tells me that the temperature sensor on the power supply is giving me a wrong reading, because the amplifier was in air conditioning, and no load was connected nor any input!

How do I fix this?

#2 joust


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Posted 31 July 2014 - 08:59 AM

Hello KC,

Replace both thermal sensors on the SMPS [heatsink]. Use the newer sensors, Crown p/n 141961-1.
You better have technical abilities because you'll need to remove the SMPS module from the chassis and conduct a few solder connections.
It is possible that one of the original sensors (or both!) may have a minute crack in its casing, causing false readings.

To measure the sensors, remove the top cover and locate the SMPS module. It is located on the left side of the amp chassis (from the front).
Locate the SMPS fan; Right behind the fan are located the SMPS heatsinks and the two sensors. The two sensors are connected to the main SMPS board.
The estimated measurement of the sensors should be around 7.5K with the controller card installed.
If you remove the controller card and redo the meassurement, you will find that a correct sensor should read 20K at normal temperatures (23°C).

Hope this helps!


#3 Kasey

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Posted 31 July 2014 - 08:54 PM

Wow. Lots of info and detail there joust. First of all, thank you! I do know my way around the soldering iron, because I used to repair electronic industrial control cards. But I do not have much experience at all repairing amplifiers, just basic replacement of small components from the old school amps. This is only my third digital amp (I own two Xti4000 also). So I am also new to the digital amps.

I have some questions: is it possible at all to post some pictures so that I may get a better idea of the components that I am looking for? Example, what is the smps and where can I purchase the thermal sensors? I live in Trinidad in the Caribbean so it is a bit difficult to get certain parts down here. Are the thermal sensors proprietary to only crown, or can I get a replacement from amazon or something? Amazon is the only easy online place I can purchase parts from, since I am living in Trinidad.

Again, thank you for your gracious assistance on this! I was a bit scared that I bought a faulty amp. I am kind of relieved that it may actually be repairable. It cost me a chunk!

#4 Kasey

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Posted 31 July 2014 - 08:56 PM

Wait I just thunk about it. Does smps stand for switching mode power supply? I will check this out ASAP.

#5 Patlover1983


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Posted 02 August 2014 - 01:30 PM

Hello Kasey,

The SMPS is the power supply, its the units that converts the AC outlet voltage to the voltages the ampifier needs to work. The sensor or sensors are located near by the heatsink, or mounted on it.

But please be carefull,there are several high voltages present that can cause serious injury! Please verify that all the capacitors (especially at the primary side) are been discarged,or discharge them by yourself with a resistor. Good luck!

#6 Kasey

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Posted 03 August 2014 - 11:36 PM

Oh ok thanks, I will check on this ASAP.