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Old 31st January 2007, 03:54 PM   #1
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Default Broken Mission Cyrus II - HELP

Hi,

I have recently been given a Cyrus Two with PSX which I was completely delighted with - it's by far the best amp I've ever had the pleasure of. However, I've just killed it. Basically, like a fool I've shorted the speaker cable with some very dodgy wiring. I was hoping it would have just popped the speaker fuses but it doesn't appear to have any?

Can anybody help me? Does it in fact have Speaker fuses? Do you know anywhere I could get it repaired?

Many many thanks
Bernard.
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Old 31st January 2007, 04:13 PM   #2
AndrewT is offline AndrewT  Scotland
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Hi,
the PSX and the Cyrus Two have internal supply rail fuses.

The PSX fuse/s have probably blown.

There is a protection circuit in the Cyrus Two, but others have reported that it is not always effective in saving the semiconductors. Hopefully your's are OK.

Tell what parts look discoloured or broken when you open the amp up.
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Old 31st January 2007, 04:17 PM   #3
Geoff is offline Geoff  United Kingdom
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Default Re: Broken Mission Cyrus II - HELP

Quote:
Originally posted by bernard boulet
Can anybody help me? Does it in fact have Speaker fuses? Do you know anywhere I could get it repaired?
Hi Bernard

No it doesn't have any speaker fuses. So far as I am aware Cyrus are still able/prepared to service the early Cyrus models. However, before going down this path I suggest you check the supply rail fuses in the PSX. If these are OK then it is likely that you have blown one or more of the output transistors.

If you feel competant to disassemble the Cyrus 2, do a little fault finding and then replace the faulty components I would be happy to talk you through the process either by email or by phone.

Geoff
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Old 31st January 2007, 04:28 PM   #4
Geoff is offline Geoff  United Kingdom
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Quote:
Originally posted by AndrewT
Hi,
the PSX and the Cyrus Two have internal supply rail fuses.

The PSX fuse/s have probably blown.

There is a protection circuit in the Cyrus Two, but others have reported that it is not always effective in saving the semiconductors. Hopefully your's are OK.

Tell what parts look discoloured or broken when you open the amp up.
You beat me to it!

There was a case reported here recently where the PSX rail fuses blew before the silicon. My adverse experience of the protection circuit failing to work was with a Cyrus 1 and the output transistors in these are far less robust than those in the 2.

It is quite possible that a visual inspection of the amp's internals will not reveal anything untoward and a multimeter reading across the legs of the output transistors will then be needed.
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Old 31st January 2007, 05:39 PM   #5
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Wow. Having only joined DIYaudio today I'm to get any reply so quick let alone such helpfulness. You guys are certainly on it with your audio.

If the fuses for the supply rails are the fuses mounted next to the mains connection - accessable without opening up the amp - then these fuses are intact.

I'll take a look inside tonight and see if I can see anything ugly.

thanks again
Bernard
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Old 31st January 2007, 05:54 PM   #6
Geoff is offline Geoff  United Kingdom
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Quote:
Originally posted by bernard boulet
If the fuses for the supply rails are the fuses mounted next to the mains connection - accessable without opening up the amp - then these fuses are intact.
No, this is the fuse for the transformer primary winding. The rail fuses are on the pcb inside the PSX housing. See the picture attached to the following post. In fact it may be helpful to you if you read the whole of that thread (it's not a long one).

http://www.diyaudio.com/forums/showt...22#post1117222
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Old 31st January 2007, 08:39 PM   #7
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Hi Bernard,
I had the exact same thing happen to me once before and, very luckily, only one fuse blew in the PSX.

Those speaker terminals are a nightmare waiting to happen. Especially when using bare metal banana plugs.
You have just reminded me to change mine to insulated ones.
Good luck and welcome to the forum.

Please exercise caution when dealing with mains powered equipment.
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Old 5th February 2007, 10:52 AM   #8
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Nice one - thanks everybody. I replaced a fuse and all is well. A better solution than 150 repair bill that Cyrus offered me!

Thanks
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Old 5th February 2007, 10:56 AM   #9
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Good news and very lucky! Same thing happened to my friend and I had to rebuild his output and driver stage...

PS there are a few threads on here detailing this problem with the Cyrus 2, have a search next time
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