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Noise power supply switching Crown I-Tech T6000.

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Category: General
Forum Name: Amp Forum
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Printed Date: 30 March 2023 at 1:08pm
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Topic: Noise power supply switching Crown I-Tech T6000.
Posted By: mj15015
Subject: Noise power supply switching Crown I-Tech T6000.
Date Posted: 16 July 2017 at 3:35pm

Hi everyone, Greetings from Argentina, I am an audio technician today I am repairing the power supply of the crown t6000 I arrived with a burned mosfet mmbf170 I replaced it and I kept walking but my doubt is because it makes noise the source? Is by the type of modulation of face (Phase Shift Modulation)? I have already controlled the whole diagram, capacitors ok, voltages +20 and -20 ok + 15v and -15 ok ref. 5v ok +180 Y-180 ok, SG3525 seems to be working well in the video the oscilloscope is showing pin 11 of the SG3525, someone who works and repairs any of these models I4000, I6000, I8000 can answer my question. I leave a link to the video where you can hear the noise; It looks like a spark jump but none of that is happening ...


Posted By: U.Viktor
Date Posted: 17 July 2017 at 5:36pm
Without seeing the main power circuit it is impossible to say the exact topology and modulation scheme used in that power supply.
The MOSFET failed looks seriously undersized in that position, it is just a half-Amper FET , I would put at least 2-3A type there.
If you see these gate driver FETS making not only the gate clocking signal but also the full power for the isolated gate drivers across the gate transformer. Driving 3 or more of the power devices I guess @50KHz or more would needs larger FET for safe operation.
Otherwise the whole floating gate driver section looks utterly over-complicated, so many CMOS gates just for local UVLO when simple and more reliable integrated solutions exists since ages? Weird..
The SG3525 drives pair of gates and flip-flops looks "poor man's phase shift modulator" anyways :-)

Posted By: mj15015
Date Posted: 15 September 2017 at 8:02pm
I really do not understand how Works  phase modulation with cmos 74hc74......





Posted By: mj15015
Date Posted: 15 September 2017 at 8:09pm

Posted By: mj15015
Date Posted: 15 September 2017 at 8:34pm

Posted By: RobinMatrix
Date Posted: 16 September 2017 at 9:49am
Jeezus ... I never bothered to look at this PSU before, but 24 power devices in the PSU?  That's a lot of work to save paying for a decent sized IGBT!

Matrix Pro Audio ::" rel="nofollow -"

Posted By: kedwardsleisure
Date Posted: 16 September 2017 at 11:59am
I always thought this generation of crowns was just the designer going a little bezerk. Since production is outsourced to China, I guess the number of parts are less of an why not fill your boots!

A couple of years ago a spilled pint on the amp rack wrote-off an entire stack of XTi's. The high-density boards went off like a box of fireworks and there wasn't alot left.


North Staffordshire

Posted By: nopamp
Date Posted: 07 December 2017 at 11:42am
Hello, have you already discovered what is the problem?
I have one unit with same problem that I will investigate this weekend in case I get time.

Posted By: nopamp
Date Posted: 10 December 2017 at 5:35pm
I think I discovered it :)
Turned it on and no longuer makes that "transformer like" noise.

Posted By: patryk1305
Date Posted: 10 December 2017 at 6:05pm
Originally posted by nopamp nopamp wrote:

I think I discovered it :)
Turned it on and no longuer makes that "transformer like" noise.

Then share your findings in case others have similar issues EmbarrassedClap

Posted By: kedwardsleisure
Date Posted: 05 January 2018 at 10:19pm
Quote I think I discovered it

Details please or it didn't happen


North Staffordshire

Posted By: geovanebr
Date Posted: 24 April 2019 at 6:50pm

Hello Everyone, could someone send me the schematics for it-6000, please?

Posted By: opacheco
Date Posted: 03 February 2020 at 4:50am

Do someone have the Schematics (complete schematics) for this amp?


Posted By: Kadro
Date Posted: 03 December 2021 at 11:49pm
I am from Uruguay but live here in Brasil, i got more information about this amp

Posted By: KK Audio
Date Posted: 03 November 2022 at 1:02pm
Hi, could you tell me how you fixed the problem please. I have an Itech that has the same fault. Many thanks KKAUDIO 

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