Speakerplans.com Homepage
Forum Home Forum Home > General > Amp Forum
  New Posts New Posts RSS Feed - Noise power supply switching Crown I-Tech T6000.
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Noise power supply switching Crown I-Tech T6000.
 Post Reply Post Reply Page  12>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
mj15015 View Drop Down
New Member
New Member
Avatar

Joined: 16 July 2017
Location: Argentina
Status: Offline
Points: 5 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mj15015 Quote  Post ReplyReply Direct Link To This Post Topic: Noise power supply switching Crown I-Tech T6000.
    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 ...

 
 
 
 
 



Edited by mj15015 - 17 July 2017 at 2:58am
Back to Top
U.Viktor View Drop Down
Young Croc
Young Croc


Joined: 04 May 2010
Status: Offline
Points: 715 		Post Options Post Options   Thanks (0) Thanks(0)   Quote U.Viktor Quote  Post ReplyReply Direct Link To This Post 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 :-)


Edited by U.Viktor - 17 July 2017 at 5:37pm
Back to Top
mj15015 View Drop Down
New Member
New Member
Avatar

Joined: 16 July 2017
Location: Argentina
Status: Offline
Points: 5 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mj15015 Quote  Post ReplyReply Direct Link To This Post Posted: 15 September 2017 at 8:02pm
I really do not understand how Works  phase modulation with cmos 74hc74......

 

 

 

 



Edited by mj15015 - 15 September 2017 at 9:12pm
Back to Top
mj15015 View Drop Down
New Member
New Member
Avatar

Joined: 16 July 2017
Location: Argentina
Status: Offline
Points: 5 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mj15015 Quote  Post ReplyReply Direct Link To This Post Posted: 15 September 2017 at 8:09pm
as
Back to Top
mj15015 View Drop Down
New Member
New Member
Avatar

Joined: 16 July 2017
Location: Argentina
Status: Offline
Points: 5 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mj15015 Quote  Post ReplyReply Direct Link To This Post Posted: 15 September 2017 at 8:34pm
Back to Top
RobinMatrix View Drop Down
Young Croc
Young Croc


Joined: 23 August 2013
Location: Kidderminster
Status: Offline
Points: 567 		Post Options Post Options   Thanks (0) Thanks(0)   Quote RobinMatrix Quote  Post ReplyReply Direct Link To This Post 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 ::http://matrixproaudio.com/"
Back to Top
kedwardsleisure View Drop Down
Old Croc
Old Croc


Joined: 20 January 2009
Location: Staffordshire
Status: Offline
Points: 4794 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post 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 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
Back to Top
nopamp View Drop Down
New Member
New Member


Joined: 07 December 2017
Location: Portugal
Status: Offline
Points: 2 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nopamp Quote  Post ReplyReply Direct Link To This Post 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.
Sincerely,
Joel
Back to Top
nopamp View Drop Down
New Member
New Member


Joined: 07 December 2017
Location: Portugal
Status: Offline
Points: 2 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nopamp Quote  Post ReplyReply Direct Link To This Post Posted: 10 December 2017 at 5:35pm
I think I discovered it :)
Turned it on and no longuer makes that "transformer like" noise.
Back to Top
patryk1305 View Drop Down
Registered User
Registered User


Joined: 13 December 2012
Location: United Kingdom
Status: Offline
Points: 488 		Post Options Post Options   Thanks (0) Thanks(0)   Quote patryk1305 Quote  Post ReplyReply Direct Link To This Post 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
Back to Top
kedwardsleisure View Drop Down
Old Croc
Old Croc


Joined: 20 January 2009
Location: Staffordshire
Status: Offline
Points: 4794 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2018 at 10:19pm
Quote I think I discovered it


Details please or it didn't happen
Kevin

North Staffordshire
Back to Top
geovanebr View Drop Down
New Member
New Member


Joined: 24 April 2019
Status: Offline
Points: 1 		Post Options Post Options   Thanks (0) Thanks(0)   Quote geovanebr Quote  Post ReplyReply Direct Link To This Post Posted: 24 April 2019 at 6:50pm

Hello Everyone, could someone send me the schematics for it-6000, please?
Back to Top
 Post Reply Post Reply Page  12>

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.05
Copyright ©2001-2022 Web Wiz Ltd.

This page was generated in 0.063 seconds.