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Old 15th May 2004, 01:38 PM   #1
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Default Why are these fuses blowing

Hi need some help on Mission Cyrus PSX amps and thought someone may be able to help me as I am a bit of an amatuer.

I have a cyrus psx combined with the cyrus II. When I swithch on the power the 2 internal 4A fuses in the psx blow.

When I switch the power on on the cyrus II, the 2 fuses in it don't blow until it is conected to the psx. This seems to tell me there is a problem with the cyrus psx? Can you help me find the problem? As I am keen to understand why rather than just take it to some repair shop and never know.


Thanks
Darin
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Old 15th May 2004, 03:08 PM   #2
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Default Fuses where invented to protect circuit.

And they really does.... the pcboard normally to not turns into fire.

But never protect a transistor!.... when it opens, transistor already died.

Something is dead inside.

Carlos
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Old 15th May 2004, 04:51 PM   #3
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Default not making much sense there carlos

I thought the forum was supposed to be helpful, not cryptic
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Old 15th May 2004, 05:27 PM   #4
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Default Re: not making much sense there carlos

Quote:
Originally posted by Darin P-B
I thought the forum was supposed to be helpful, not cryptic
Destroyer speaks English as a second language, so although his replies may seem cryptic, they do actually make sense!

He is suggesting that the problem is with the power transistors in the PSU, they have blown, and that is causing the fuses to go.

I personally know just enough to be dangerous as regarding high power PSUs, but if your patient I'm sure someone will be along to help soon!
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Old 15th May 2004, 05:32 PM   #5
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There might be a problem with the amp as well. A fault on the amp (short circuit somewhere) could have caused the psu to fail.

If the psu is not regulated the component/s most likely to fail would probably be the rectifer diodes / bridge. With the power off check these using a multimeter with a diode test setting.

If the psu is regulated the number of possible failure modes makes remote diagnosis somewhat difficult.
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Old 15th May 2004, 05:54 PM   #6
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Default Sorry darin, but pinkmouse got the whole idea

Not first time people think i was doing critics or something alike.

Really sometimes i made small jokes and also put in parenthesis (hahaha) to make people understand the way is written.

But normally not, i like to be helpfull, unfortunattelly no enough knowledge to help many people.

I think my smiling face, in photo, can be the trouble.... i am thinking in change it... this smile can be hard for some people....i will put something more serious because someone told this is ironic face.

When this picture was taken, my small and loved daughter was learning how to take pictures with old film machines.... the smile is a kind way to look at her.... an acceptance smile because she could, so small girl, do this job without problem... also is a proudy smille because i think my daugther is wonderfull.

But, someone can think this is is a smilling to you!.... this smile means, I AM SMILLING TOGETHER WITH YOU, ACCEPTING YOU!

Sorry again... speak portuguese.... me speak indian, me go!

Carlos
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Old 15th May 2004, 06:10 PM   #7
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Carlos

You don't need to change anything, we like you the way you are!
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Old 15th May 2004, 06:58 PM   #8
Kees is offline Kees  Netherlands
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I can imagine that you cannot just connect a PSX to a Cyrus amp.
I think the PSX is a power supply for the power output stage.

What happens may be that you connect 2 power supplies in parallel, which is not allowed.

Inside the Cyrus amp you should disconnect the power supply from the final stage, and then connect the PSX.

I hope this helps.
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Old 16th May 2004, 11:47 AM   #9
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Thanks for the replies, and sorry Carlos if I took you the wrong way - new to this forum.

I think I may have got the 2 Cyrus bits mixed up so will correct here-

I have a cyrus II (integrated stereo amplifier) combined with the cyrus psx (external DC power supply for Cyrus II). The Cyrus psx plugs in to the Cyrus II (blue cord female 3 pin +40 -40 Volts DC). Both units also have their own pwer supply cables from mains.


When all conected and I swith on the power the 2 internal 4A fuses blow in each of the Cyrus psx and the Cyrus II. With the 2 fuses blown in each unit both power lights still come on at the front.

When I switch the power on on the Cyrus psx, the 2 fuses in it don't blow until it is conected to the Cyrus II. This seems to tell me there is a problem with the cyrus II?

Can you help me find the problem? As I am keen to understand why rather than just take it to some repair shop and never know.

Hopefully it is now a bit clearer for somebody to help me.


Thanks
Darin
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Old 16th May 2004, 12:59 PM   #10
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If I remember correctly, the PSX is an optional upgrade to the cyrrus amps, so you could try running the amp on it's own, and see if you can isolate the problem to a particular unit.

What do you have available in the way of test equipment?
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