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Crown K2 acting up


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#1 Deromax

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Posted 09 November 2012 - 12:57 PM

Hello!  It's my turn to ask for help!  :)

I have a Crown K2 that have an intermittent problem, it's like it won't stay powered.  You turn it ON, it will stay ON for 2-3 seconds, then shut down.  Going OFF-ON-OFF-ON several times and eventually it will latch ON and stays.  I then let it alone and it can be OK for weeks.

I have a service tech into this and troubleshooting suggestions would be apreciated.  Seems the relay that bypass the turn-on surge protection resistor is not getting activated.

That's a very early unit.  Actually, I brought the amp at the service place to have the power-saving function time-out modded so the time constant is longer, per Crown official procedure.  And the issue poped again while at the service shop.  I should have left the thing alone in my rack!  :/

Thanks!

#2 dakos

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Posted 12 November 2012 - 12:52 AM

Despite my strong will to help, this is too hard core for me, we'll wait for Alain (joust) to respond...

#3 Deromax

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Posted 17 November 2012 - 01:46 PM

An update!

My repair man is pulling out his hairs trying to understand the amp!  It's really a complex design.  Crown is offering little help beside peddling new boards outright, at an expensive cost as you may imagine.  My amp was purchased used, was already repaired more than once in its life and in a bad way it seems.  A mess!  :/

Repair man will try to arrange things and the jury is still out as far as success is concerned.  This is the price to pay to have the only 2500 watts fan-less amp available, past or present.

#4 techie47

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Posted 20 April 2013 - 02:51 AM

There ia a video on you tube about the K1 and k2 repair. The guy talks about some caps the capacitors needing replacement and causing this on off problem. It's a lot of caps to change.

#5 Deromax

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Posted 20 April 2013 - 11:10 PM

I had forgotten about this thread!

My K2 was repaired successfully and at a reasonable cost.  It's performing great now, powered since last december!   I love the new longer time constant too!

Thanks for the info.  I'll look it up.

#6 joust

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Posted 22 April 2013 - 11:57 AM

Thank you Dakos!

This verification should be done to any K1 or 2 that comes in for repair: Verify and measure all 100uF 25V caps in the smps section; Especially C23 and C24! in the negative 13V generation and supply. If you measure less than 90uF, replace the cap.

This amp is probably a 1999 to 2002 model. In the late 90s, a scientific engineer in a Taiwanese capacitor manufacture left the building with the recipe. The Taiwanese manufacturer decided to brew the recipe on their own with drastic effects: millions of electrolytic caps were badly produced and a slew of computer malfunctions started to appear. Blown caps with their dome all distended were discovered in the faulty psus. (Google the story!).

For those who have this following symptom: powering up and the start-up relay is just clicking away: power down; Remove the scr and you should not have the realy clicking anymore. You can now troubleshoot easily. Do not load the outputs! :)

Alain

#7 joust

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Posted 22 April 2013 - 11:58 AM

BTW, this should have been posted in the Amplifier Troubleshooting page.

Alain