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Buzzing "relay" in PS-200 at turn-on


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#1 Crown since 1974

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Posted 14 December 2010 - 11:45 PM

One of my PS-200s has developed a problem with the clear-plastic cube "relay" on the circuit board above the power switch, visible with the top cover of the amp removed.
The box is marked "Japan" with a four-digit number printed on it and has four contacts to the circuit board.
On turn-on it will sometimes buzz for several seconds as if the relay contacts are dirty or aren't getting enough voltage to close. Eventually, usually, it will "lock" in the closed-circuit mode and all is well. When it buzzes, all the four red LEDs on the faceplate light up and flicker. I can see the "relay" fork attempting to close the contacts but they won't stay closed.

What is this part? I'm guessing part of the turn-on delay?
Is this a replaceable part that's still available from Crown? (Couldn't find a part listed on the circuit diagram.)
Symptomatic of some other ailment?
Is there a way to open the relay's box to clean it or will it shoot small parts all over the room?
If I drill a small hole in it and either blow it out or shoot it with DeOxit is it likely to cause any problem (other than if I drill into the circuit, of course!)?

Thanks for any help. First problem I've ever had with a PS-series amp out my five!  sad.gif

#2 sharkmon

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Posted 15 March 2011 - 10:11 AM

QUOTE(Crown since 1974 @ Dec 15 2010, 12:45 AM) View Post
One of my PS-200s has developed a problem with the clear-plastic cube "relay" on the circuit board above the power switch, visible with the top cover of the amp removed.
The box is marked "Japan" with a four-digit number printed on it and has four contacts to the circuit board.
On turn-on it will sometimes buzz for several seconds as if the relay contacts are dirty or aren't getting enough voltage to close. Eventually, usually, it will "lock" in the closed-circuit mode and all is well. When it buzzes, all the four red LEDs on the faceplate light up and flicker. I can see the "relay" fork attempting to close the contacts but they won't stay closed.

What is this part? I'm guessing part of the turn-on delay?
Is this a replaceable part that's still available from Crown? (Couldn't find a part listed on the circuit diagram.)
Symptomatic of some other ailment?
Is there a way to open the relay's box to clean it or will it shoot small parts all over the room?
If I drill a small hole in it and either blow it out or shoot it with DeOxit is it likely to cause any problem (other than if I drill into the circuit, of course!)?

Thanks for any help. First problem I've ever had with a PS-series amp out my five!  sad.gif


There is a good chance that C4 on the little board with the relay you speak of is bad.  There was an update for that cap many moons ago, and your amp may not have gotten it.  Or, due to age and use (I think more due to age) it doesn't work as it should.  Replace it with an electrolytic cap, 10uf at 100V.  I think the original designed cap was less than 100V and that was why the update happened.  The Crown part number for the replacement cap is C 8889-5, if they still have it.  If you have to search for an alternate part, do not go lower on the voltage rating!  No problem to go higher.  Also, PAY ATTENTION to the polarity of the old cap BEFORE you take it out.  Put the new one in backwards, be prepared to buy another one, clean up a mess in your unit, and a loud BANG!

Hope this helps.

#3 Crown since 1974

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Posted 21 April 2011 - 11:08 PM

QUOTE(sharkmon @ Mar 15 2011, 11:11 AM) View Post
There is a good chance that C4 on the little board with the relay you speak of is bad.  There was an update for that cap many moons ago, and your amp may not have gotten it.  Or, due to age and use (I think more due to age) it doesn't work as it should.  Replace it with an electrolytic cap, 10uf at 100V.  I think the original designed cap was less than 100V and that was why the update happened.  The Crown part number for the replacement cap is C 8889-5, if they still have it.  If you have to search for an alternate part, do not go lower on the voltage rating!  No problem to go higher.  Also, PAY ATTENTION to the polarity of the old cap BEFORE you take it out.  Put the new one in backwards, be prepared to buy another one, clean up a mess in your unit, and a loud BANG!

Hope this helps.
Thanks! What I think is C4 (indicated by red arrow at lower left in photo below) is marked 6.8uf at 50v. The schematic in the PS200 manual shows C4 as 10uf at 50V. I can't see the mark on the board for the component number but maybe it's underneath the cap? The part listing on-line at Crown for the PS400 shows C4 as part number C3728-0 that supersedes C5050-7. It gives no indication of value for C5050-7. Could my 6.8uf have been superseded by a 10uf? Am I looking at the right cap?? (see red arrow at bottom left of photo)? Is the part for the PS400 the same as the PS200? What difference will 6.8 versus 10.0uf make??

Thanks for helping someone who can barely tell a resistor from a capacitor! (But I have replaced caps in a DVD player with success.)




#4 Crown since 1974

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Posted 24 January 2012 - 01:59 AM

Thought I'd bump this thread as I've yet to attempt a repair. Still wondering if someone can ID the suspect offending component from the photo.

Thanks in advance for any assistance.

#5 Crown since 1974

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Posted 28 May 2012 - 07:01 PM

Bumpity bump.


#6 karlos the dc300a

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Posted 05 July 2012 - 01:03 PM

what about the black electrolytic cap near c1?, (i take it c1 is the red cap?) i would change all the electrolytic caps.

there are a couple of black electrolytic capacitors on the board that i can also see, they are vertically mounted with a silver top visable.

in your pic they are top middle and bottom middle.