Re: Creative S750 AMP board, there's reading value on one board, no reading value on
Sad story, power it on and got at least one STA575 chip fried (See attachment 2, video). This is the same phenomenon when I got this subwoofer.
Resistance between +Vs and GND and CD-1 pin of one STA575 is less than 100 Ohm in both direction. (See attachment 1, photo)
In the video, you can see when I switch power on, it goes to standby mode. In standby mode, +24V and GND and -24V already reached the AMP board, so I assume there's no serious issue on +24V and GND and -24V...
moontide
饿了就吃，困了就睡，保持原始
Last Activity: 07-08-2021, 02:00 AM
Joined: 05-24-2016
Location: ShenZhen, GuangDong
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Re: Creative S750 AMP board, there's reading value on one board, no reading value on
Yes, I think that too.
Just did the following test:
Clean solder of [CD-1](#1) & [CD-2](#27) & [GND](#13) pins of three STA575 power amplifier chip, measure again using diode switch, then there's no reading value now.
Then I measure [GND] pin to [CD-1] pin of each STA575 chip, there's no reading value too, which means these new STA575 chips (old chips are failed, and were replaced) are not failed.
And then, I tried to push the pins of STA575...Last edited by moontide; 03-23-2018, 12:22 PM.Leave a comment:
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Creative S750 AMP board, there's reading value on one board, no reading value on anot
I'm trying to repair the subwoofer (MF7010) of S750 speaker.
I managed to replaced some obviously failed parts on AMP board 2, after that, when I use diode switch of multimeter to measure two pins, something interested happened.
The power input of AMP board has five pins:
[[color=red]+24V[/color]] [-24V] [GND] [70V+] [70V-]
[list][*]When I put RED probe on [GND], BLACK probe on [-24V], there's a reading value (1.98x or 1.99x).[*]If I measure same pins on another AMP board of another speaker, there's no reading value (actually, the multimeter displayed '1'...Last edited by moontide; 03-23-2018, 12:02 AM. -
Re: Creative S750: back LED & control pod LED are okay, but unable to power up
Okay, after weeks struggle, I may fixed this subwoofer after replaced the optocoupler (U2) in the feedback circuit.
Since I suspect U2 (optocoupler) and U3 U4 U5 U6 and T3 and electrolytic capacitors in the feedback circuit, I began to replace those components from easy (electrolytic capacitors) to hard (Transformer 3).[LIST=1][*]I replaced all the electrolytic capacitors in the feedback circuit, not helping[*]Desoldered optocoupler, clean some dark gray explosion dust/stuff, solder...Leave a comment:
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Creative S750: back LED & control pod LED are okay, but unable to power up
Half a year ago, [URL="https://www.badcaps.net/forum/showthread.php?t=54784"]I repaired my S750 woofer[/URL].
Half a month ago, I bought a failed S750 woofer to repair for fun (I'm still a newbie). There were some obvious failed parts on the PSU board I checked, and I may fixed them.[LIST][*]D9 - 1N4004 - short circuit, replaced.[*]D13 - 1N4148 - short circuit, replaced.[*]R9 - 6.8Ω, 1/4W - open circuit, replaced.[*]U7 - TOP243Y - it was replaced with a TOP249Y by the previous owner, I don't know if it's okay, but I replaced it with a new TOP243Y. And the solder pads...Last edited by moontide; 12-25-2016, 04:25 AM. -
Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Good news, after long time fixing (or perhaps damaging), I had fixed my speaker issue.
Long story in short, I replaced U1 ([url=http://www.tgahinfo.homecall.co.uk/S750%20PSU/Data%20Sheets/stabp01.pdf]STABP01D[/url], the 20 pins chip) and/or Q5 (near U1).
Two STABP01D chips, one good, one bad (right one).
[ATTACH]137098[/ATTACH]
The voltage output between #8 pin (MAIN OUTPUT to Q1 gate pin) to #9 pin (GND or actually 70V-) is very low,...Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Found a small bulge on the brown capacitor, could it be failed? There's no voltage (neerly zero) between two legs of this capacitor, while on the other board, it's around 6V...Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
I measured +Vs -Vs CD+1 CD-1 CD+1 CD-2 of one STA575 chip, found that voltage input of CD-1 and CD-2 is almost 0V, that's not right. According the datasheet of STA575, it's operating range should be between -20.7V to -3V.
Since there's not schematics of power amplifier board, I think I need to trace the line on PCB board, that's could take me long time to do that ......Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Bad news, I soldered 3 new 4.7μF capacitors up, didn't make speaker work, even worse, it returned to "no sound / distort sound in low volume on (Center & Subwoofer & Side Left & Side Right) channels" state.
Even changed all electrolytic capacitors, and even disassembled the connector of audio cable which connected audio I/O board & power amplifier boards to clean glues [ATTACH]135707[/ATTACH], still no sound / distort sound on Center & Subwoofer...Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Good news, after solder two 4.7μF capacitors down,[list][*] [color=green]Side Left & Side Right channel have sounds now. [/color][*] [color=brown]Center channel has sound with low volume (at least it has sound).[/color][*] [color=brown]Subwoofer has sound too, but not enough (like only has middle range frequency)[/color], it may related missing of the two bad capacitors (of course?)[*] Volume of Side Left channel is still a little bit lower. maybe related to other capacitors which has...Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
My stupid mistake again:
I plugged the audio cable which connected audio I/O board and two power amplifier board in wrong way on the audio I/O board, hence no sounds.
Now, I corrected this stupid mistake, sounds came out from Front Left & Front Right & Rear Left & Rear Right, but no sound on (Center & Subwoofer & Side Left & Side Right), and the subwoofer is not actually silent, but distort noise (see the attachment or [url=http://img.vim-cn.com/24/754d1272f973f96405edb9a668264fc0439262.mp3]here[/url])...Leave a comment:
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Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Well, I replaced C201 capacitor on audio I/O board with a new [url=https://item.taobao.com/item.htm?id=523840294666]Sanyo OS-CON 100μF 16V[/url], the volume of left channel in earphone which plugged into earphone jacket on control POD are normal now.
But still, no sound come out from any speaker.Re: Creative S750 speaker no sound, power LED & control POD LED are ok
Well, I replaced C201 capacitor on audio I/O board with a new [url=https://item.taobao.com/item.htm?id=523840294666]Sanyo...Leave a comment:
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Creative S750 speaker no sound, power LED & control POD LED are ok
Currently, my S750 speaker has no sound output from any speakers.
[size=5]The symptom now[/size][LIST][*]The power LED on the subwoofer back pane is steady green, and I can power on the speaker -- the power/standby LED on control POD indicate it is powered on.[*]The volume LEDs on control POD also indicated that I can also adjust the volume[*]There're sound output from the earphone if the earphone is plugged on the control POD, but the left channel has very very low volume (closed to quiet), I have to increase the volume to hear sound from the left channel[*]This issue is like same... -
Re: New Members - please post your introductions here
Hi everyone, my Creative S750 speaker have no sound now.
After searched internet, this site come up.
I don't have enough knowledge about electronic stuff, I'm need for help about this issue.
I'll post a new thread for detail information.Leave a comment:
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