Amplifiers Rescue Gods |
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Lucasdude
Young Croc Joined: 16 March 2013 Location: London Status: Offline Points: 827 |
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Graphic needs some new graphics!
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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Yeah
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EmPro Audio
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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From a fried HH S500d i rebuilt a couple of years ago. Basically it had 3 shorted output devices,and that then took out every transistor on this driver board, and a dozen passive components too.
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Be seeing you.
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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Rebuilt module.
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Be seeing you.
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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Is it true that S500D doesn't have any dc output protection?? If that module was so bad i assume the speakers had no chance
i'm a HH fan,i have: HH V-S Musician combo 2x12,with 100w rms in 4r and quasi comp 2x2n3773 as outputs,HH MA150 amplifier,150w rms with 2XBDY37A as outputs,HH SM200 powered mixer 2x100w rms with two modules with 2x2n3773 on outputs,HH V800 2x400w rms in 4R with 8 lateral hitachi mosfets per ch 4x2SJ50 and 4X2SK135,also i have 6 HH M900 (basicaly HH V800 install version).
Edited by EmPro - 28 May 2022 at 1:59pm |
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EmPro Audio
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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EmPro Audio
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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This was common on amps from that era, S500d, Crown DC300a, Phase Linear 700b, MM AP 360, none of them had any DC protection. Speaker fuses need to be fitted in-line. Martin Audio even fitted big electrolytic caps into their bass cabinets to protect the drivers. |
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Be seeing you.
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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Here i have a Crown D75,the fault was just one output transistor....yeah...strange..all the other components perfectly fine lol,ofcourse i replaced both outputs,the drivers where totaly fine so no need replace,the amp is working flawless now,tested in heavy load untill the case temperature got 50-55c:
Edited by EmPro - 28 May 2022 at 2:02pm |
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EmPro Audio
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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yeah...i got the point mate,cheers.
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EmPro Audio
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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This HH MA100 was a case of some sort of liquid damage as the marked circuits was covered in some sort of sticky thing,C7 was exploded and all the other capacitos where done...strange but true...all the transistors survived,predrivers,drivers and outputs all original,so after full recap and one resistor replaced related to C7 i fired it up and surprise: 47vcc on outputs with all the parts measured with Fluke177 and shows good....then only one remains...the TL741 (UA741)...after replacement 0.037mv on outputs and fully working order,somehow the IC was putting out 6vcc on pin 6 (output pin) but the zenner diodes responsabile with +-15vcc supply were good.
Edited by EmPro - 30 May 2022 at 2:21pm |
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EmPro Audio
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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By the way, those 100w HH pa/guitar amps also had no protection, so will take out a speaker with 47vDC just as easily as a bigger one.
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Be seeing you.
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EmPro
Young Croc Joined: 26 June 2020 Status: Offline Points: 766 |
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Yeah i know ,but not so easy to blow up one
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EmPro Audio
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