Author Topic: Wanna see my 67 Coliseum PA Head??  (Read 5997 times)

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Offline Stackedsunn

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Re: Wanna see my 67 Coliseum PA Head??
« Reply #14 on: June 12, 2009, 04:39:12 pm »
I rehearsed with it 2 nights ago and it completely died !  I found out it was a cracked solder joint....the green wire coming out of the transformer have a tiny melted spot on them, but once the cracked solder joint was fixed it was back to the way it was...

Has anyone had any issues with GREEN wires melting in any old Sunn Amps ??

I am thinking of playing it a few more times b4 I sent it back to the shop to possible get those green wires replaced.....I don't want to cook the transformers...

Anyone been down this road ??????

Offline loudthud

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Re: Wanna see my 67 Coliseum PA Head??
« Reply #15 on: June 12, 2009, 06:56:16 pm »
The green wires usually won't melt in one spot. It's possible someone nicked the wire with a hot soldering iron. Make sure your amp has the correct fuse. My 2000S uses a 5 amp.

Offline mckinnon audio

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Re: Wanna see my 67 Coliseum PA Head??
« Reply #16 on: June 13, 2009, 07:24:50 am »
    Hi there,the green wires coming out of your trans. are the heater winding for all your tubes,that's why the amp shut down,no heater voltage.Depending on the amp,there could be a few amps of current running through them,(green wires).The byproduct of a bad connection is heat,and sometimes this will melt wires.I've seen lots of burned up trans. and htr. lines,there are a few things you can do to protect them,some people fuse the htr. center tap wire,(the green one with the yellow stripe),or you can disconnect it and add a 100 ohm 1/4 watt resistor from each of the htr.lines to ground,this way if your htr.'s short to ground,the resistors act like fuse links and blow saving the htr. winding on the trans.Hope this is of some help,Mel.

Offline Stackedsunn

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Re: Wanna see my 67 Coliseum PA Head??
« Reply #17 on: June 13, 2009, 04:56:14 pm »
I understand....just wondering if I should run the amp for a week or 2 and see what happens or if I should either ground the green wires or have them replaced......this is a rare amp and I don't want to blow a transformer..