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Cary 300SEI blew 2 fuses (bad tube or ???)

172.9.185.95

I was using it to play background music at very low volume for hours while working in another room. It sounded good throughout but the room ambient temperature was hot (upper 70F). Then suddenly the music stopped. The amp lost power and I noticed a faint burning smell in the room. I checked the fuse and it was blown. I let the amp cool down a bit and then put in the replacement fuse (factory rated 2A 250V slo blow). I turned the bias all the way down first before powering it back on. The light in the room dimmed a bit and the replacement fuse immediately blew. It didn't even make it pass the soft start stage this time around. I opened up the hood and didn't notice anything abnormal except minor overheating / burnt marks on the leads of one of the caps (see photo). How can I tell if it's a bad tube or the amp needs professional repair? I bought it used 13 years ago so it's at least 20 years old.

Does anyone know any good tube tech in SoCal or I should just send it back to Cary?

Thanks

Follow Ups:

RE: Cary 300SEI blew 2 fuses (bad tube or ???) - ishmael39@earthlink.net 18:03:29 10/31/22 (0)
It looks like a 300B shorted through. Start by testing the tubes. The put an ohm-meter accross that resistor.

A new tube and maybe a new resistor may be all you need.

Maybe

hr
RE: Cary 300SEI blew 2 fuses (bad tube or ???) - ishmael39@earthlink.net 17:41:03 10/31/22 (0)
It looks like a 300B shorted through. Start by testing the tubes. The put an ohm-meter accross that resistor.

A new tube and a new resistor my be all you need.

Maybe

hr
RE: Cary 300SEI blew 2 fuses (bad tube or ???) - Mick Wolfe 11:12:59 08/27/22 (0)
I would let a reputable tube tech go thru the amp and do a total update.
The main issue will be finding someone really competent and local of course. This is where some SoCal inmates might hopefully chime in. A competent tech could easily refurb that amp. Shipping it to and from Cary would cost a fortune, but in the end, your call.
The 2 fuses - Funky Bob 09:40:35 08/27/22 (5)
.
- RE: The 2 fuses - Tre' 14:48:33 08/27/22 (4)
  Bring it over and we can test the tubes then we'll bring it up slow on the variac with current meter. I also have a cap checker. The one thing we know for sure, something is drawing too much current.
  
  I'm in Ojai.
  
  Tre'
  Have Fun and Enjoy the Music
  "Still Working the Problem"
  - my money is on a bad cap.~nT - Cleantimestream 00:58:16 10/13/22 (1)
    ~!
    The Mind has No Firewall~ U.S. Army War College.
    - You could very well be right. nt - Tre' 17:28:12 10/13/22 (0)
      .
      Have Fun and Enjoy the Music
      "Still Working the Problem"
  - You just got an offer from an extremely competent hobbyist.. - viridian 19:03:56 08/27/22 (1)
    ..I would take him up on it. And that is not a capacitor, it is a dropping resistor in the power supply. All the more reason to have Tre help you out. I would be asking him what his favorite adult beverage is as we speak.
    - +1.. - Mick Wolfe 10:13:51 08/28/22 (0)
      NT

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