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Carver M400 Output Transistor Issue

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tfm75

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SILVER-7t

Posts: 1191

Joined: Fri Feb 03, 2006 6:37 pm

Post Sun Sep 28, 2008 8:54 pm

Re: Carver M400 Output Transistor Issue

Robert R wrote: Meanwhile, I looked and found that at the Fest I got a beautiful file copy of the service manual from Tim AKA TFM-75 , and besides being clear and readable, it's VERY thorough, compared to most such productions.
RobertR
Between FrankieD and I we have logged in over 12,000 miles going and coming from Carverfest's. Don't let the miles in between play with your mind. Get over it, jump on a plane get to the fest and have a great time !
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jdcglasnost

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Joined: Tue Sep 16, 2008 4:56 pm

Post Sat Oct 04, 2008 11:13 am

Re: Carver M400 Output Transistor Issue

Got all new caps and the transistors replaced, (had to modify the fuse for the filter caps... grrr) and now... well it sits with a poping noise ... I'd best desciribe as the amp having bad gas in short bursts with the level display lights going nuts (seriously, thats the best techno term I can come up with <.<). Ugh, so I've been digging and found some referances to the triac being prone to issues so I'm off to check it out. Short on ideas on this one, also I did make one bobo, I didn't mark one of the main screw filter caps for polarity. This would be the one on top when the unit is assembled, I assumed like most PSU's I've worked on the The bottom filter caps "+" goes to the the "-" of the top filter cap, leaving the "+" for the top facing the top of the amp, just want to send that out there to double check myself. Well I'm off to check out the triac, and some wiring. More looking for an idea now, original issue was one bad channel, now it seems I've got two working channels... that have gas.... ](*,) .

-John
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BillD

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(pair of) SILVER-7 TUBE AMPs

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Location: The west's most mid-western town, Scottsdale, Arizona

Post Sat Oct 04, 2008 1:19 pm

Re: Carver M400 Output Transistor Issue

Two working channels means you probably fixed your channel problem and created a PS problem. The triac in those puppies is pretty tough, but there's a diac that could need replacing. Still, the popping sounds like a cap problem, and I'd check my soldering and that polarity question that you have.
It should sound like it isn't there!
There is a difference between hearing and listening...
Making life enjoyable through expensive electronics.
_________________
Carver: C-4000 & C-1 preamps, PSC-60 preamp/tuner, TX-11a tuner, M-400 (2), C-500, M-500, M-500t, M-500t Mk.II, A-500x, AL-III loudspeakers (2 pr.)
Sunfire:Theater Grand III processor, Ultimate Receiver, Cinema Grand Signature 400 ~ seven, True Subwoofer Mk. II, D-10 Subwoofer
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jdcglasnost

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Joined: Tue Sep 16, 2008 4:56 pm

Post Sat Oct 04, 2008 1:49 pm

Re: Carver M400 Output Transistor Issue

Well next I'm off to a friends house to use his scope and to really get into this amp. I'll test the Triac then, the Diac on those huh, hmm, gets me thinking, but anywho. At this point, unless its a non electrolytic cap, its not a cap, the rest of them I marked polarity wise, and I'm 99.9% sure I have the Main filter cap I didn't mark right (marked one, removed the other sat it down and went "opps" #-o ). I'll get to all that testing, but what I really need now are referances for what voltage is suppose to be where or even a PS schematic to just make it easyer (and more lazy for me). Thank you for the Diac suggestion,

-John
P.S. My solder joints never have issues 8-[
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docadillac

TFM-25

Posts: 357

Joined: Sun Aug 24, 2008 12:09 pm

Location: The wet coast of Canada

Post Sun Oct 05, 2008 1:51 pm

Re: Carver M400 Output Transistor Issue

I wish I was as brave as you guys to try to rebuild electronics gear. I am more at home with a tear down on a big block ford than anything else. I am a bit on the clumsy side with small parts and absolutely stupidly dangerous with a soldering iron.
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jdcglasnost

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Posts: 7

Joined: Tue Sep 16, 2008 4:56 pm

Post Mon Oct 06, 2008 6:46 pm

Re: Carver M400 Output Transistor Issue

docadillac wrote:...stupidly dangerous with a soldering iron.
This needs to be an album name, but back on track thank you BillD, your help will get this going when I get over to see what this little guy is doing on a scope.... But till then here some pics of my boston A400's, cause you need some eye candy to hold you guys over \:D/
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IMG_0311.jpg
Without Grill
IMG_0311.jpg (551.33 KiB) Viewed 347 times
IMG_0310.jpg
With Grill
IMG_0310.jpg (527.39 KiB) Viewed 348 times
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sdmorrison

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Posts: 3

Joined: Fri Dec 19, 2008 5:13 pm

Post Fri Dec 19, 2008 5:35 pm

Re: Carver M400 Output Transistor Issue

Hi there,

I have a M-400t that had one channel making the dying transistor sound, now it just blows the fuse on power up everytime, so I figure the complementary pair to the bad transistor must have finally gone too.

I also figured I should replace all of the output transistors while I have it apart, so I am wondering which are the NPN and PNP? The case numbers for the M-400t's T-O3 devices are C4000 8413, C4000 8352, C5000 8339, C10000 8339, and C11000 8413.

Can I use the MJ15024 and MJ15025 to replace all 12 devices?

Thanks,

Stephen
Attachments
PC180080.JPG
PC180080.JPG (457.62 KiB) Viewed 299 times
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sdmorrison

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Posts: 3

Joined: Fri Dec 19, 2008 5:13 pm

Post Wed Dec 24, 2008 12:06 pm

Re: Carver M400 Output Transistor Issue

Anyone? :-s
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BillD

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 7295

Joined: Wed Jun 06, 2007 8:29 pm

Location: The west's most mid-western town, Scottsdale, Arizona

Post Wed Dec 24, 2008 1:22 pm

Re: Carver M400 Output Transistor Issue

Steven, you might try to PM jdcglasnost to see how he's doing with his. He replaced the output transistors.
It should sound like it isn't there!
There is a difference between hearing and listening...
Making life enjoyable through expensive electronics.
_________________
Carver: C-4000 & C-1 preamps, PSC-60 preamp/tuner, TX-11a tuner, M-400 (2), C-500, M-500, M-500t, M-500t Mk.II, A-500x, AL-III loudspeakers (2 pr.)
Sunfire:Theater Grand III processor, Ultimate Receiver, Cinema Grand Signature 400 ~ seven, True Subwoofer Mk. II, D-10 Subwoofer
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RichP714

SILVER-7t

Posts: 1814

Joined: Fri Oct 12, 2007 2:12 pm

Post Wed Dec 24, 2008 1:50 pm

Re: Carver M400 Output Transistor Issue

sdmorrison wrote:.....
Can I use the MJ15024 and MJ15025 to replace all 12 devices?

Thanks,

Stephen
Yes
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BillD

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 7295

Joined: Wed Jun 06, 2007 8:29 pm

Location: The west's most mid-western town, Scottsdale, Arizona

Post Wed Dec 24, 2008 2:43 pm

Re: Carver M400 Output Transistor Issue

Rich, why were they different in the original model?
It should sound like it isn't there!
There is a difference between hearing and listening...
Making life enjoyable through expensive electronics.
_________________
Carver: C-4000 & C-1 preamps, PSC-60 preamp/tuner, TX-11a tuner, M-400 (2), C-500, M-500, M-500t, M-500t Mk.II, A-500x, AL-III loudspeakers (2 pr.)
Sunfire:Theater Grand III processor, Ultimate Receiver, Cinema Grand Signature 400 ~ seven, True Subwoofer Mk. II, D-10 Subwoofer
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RichP714

SILVER-7t

Posts: 1814

Joined: Fri Oct 12, 2007 2:12 pm

Post Wed Dec 24, 2008 4:01 pm

Re: Carver M400 Output Transistor Issue

BillD wrote:Rich, why were they different in the original model?
It's cheaper . The M-1.0t does a similar thing....the low tier is different than the mid and high tier, SOMETIMES. The used lower V devices on the low rail, but the higher V devices work fine, and some M-1.0t used the same PN on all tiers.
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sdmorrison

Newbie

Posts: 3

Joined: Fri Dec 19, 2008 5:13 pm

Post Wed Dec 24, 2008 10:45 pm

Re: Carver M400 Output Transistor Issue

Great. Thanks for the help, I appreciate it!

Happy Holidays.

Stephen
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