Noise power supply switching Crown I-Tech T6000.
Printed From: Speakerplans.com
Category: General
Forum Name: Amp Forum
Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=98896
Printed Date: 30 March 2023 at 1:08pm
Software Version: Web Wiz Forums 12.05 - http://www.webwizforums.com
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
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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 ...    |
Replies:
Posted By: U.Viktor
Date Posted: 17 July 2017 at 5:36pm
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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
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I really do not understand how Works phase modulation with cmos 74hc74......
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Posted By: mj15015
Date Posted: 15 September 2017 at 8:09pm
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Posted By: mj15015
Date Posted: 15 September 2017 at 8:34pm
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Posted By: RobinMatrix
Date Posted: 16 September 2017 at 9:49am
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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 :: http://matrixproaudio.com/" rel="nofollow - http://matrixproaudio.com/" |
Posted By: kedwardsleisure
Date Posted: 16 September 2017 at 11:59am
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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 issue...so 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. ------------- Kevin North Staffordshire |
Posted By: nopamp
Date Posted: 07 December 2017 at 11:42am
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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. Sincerely, Joel |
Posted By: nopamp
Date Posted: 10 December 2017 at 5:35pm
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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
Then share your findings in case others have similar issues
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nopamp wrote:Posted By: kedwardsleisure
Date Posted: 05 January 2018 at 10:19pm
Details please or it didn't happen ------------- Kevin 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
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Hi, Do someone have the Schematics (complete schematics) for this amp? Thanks opacheco.
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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 |