New CR-840 Experience

CARNICK

New Member
Picked up a new CR-840 a few weeks ago and after opening the cover and plugging it in I determined that it was really trashed. Layers of dust and dirt covered everything (including the infamous pre-drivers –parts with no replacements)!
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Also, the left channel seemed weak – really weak – and no lamps. I was about to kick it to the curb, but decided to give her a chance. So I started vacuuming, cleaning, detoxing, and lubing. I brushed and wiped everywhere possible then took the CyberClean compound to it. After a few hours things started to look better and the sound was better.

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More deox and lubrication helped and the left side came back! Removed the knobs and dissembled the fascia. Got everything cleaned up with Windex and Magic Eraser and by now it was looking really good and sounding clearer! Installed new lamps (green glow in the dark is cool!!) – the old 840 was almost good as new!!! Sounds great now and looks almost new.

Still need to deal with the Yamaha pre-drivers – any/all advice is welcome. I read that heat sinks may help preserve them?? Is it really true that there is no way to replace these components??
 
New Lamps Pics

Here are the new lamps in my CR-840:
 

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Where did you get the lamps !? I just got one a few weeks ago as well and I'm missing 5 lamps . I love this thing , it sounds fantastic . Yours looks really nice too .
Rudy .
 
Where did you get the lamps !? I just got one a few weeks ago as well and I'm missing 5 lamps . I love this thing , it sounds fantastic . Yours looks really nice too .
Rudy .

dgwojo.com
 
And I thought mine was dirty! :yikes: At least it appears you just had dust - mine was cat hair and dander - corrosive stuff.

Here's how I keep my pre-drivers cool...

http://www.audiokarma.org/forums/showpost.php?p=6128467&postcount=60

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But if one does kick-the-bucket anyway, there is hope... Chazix has managed to put together a pre-driver board out of discrete components. Should work for 640/840/1040.

http://www.audiokarma.org/forums/showthread.php?t=500309
 
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I have a couple of dead CR-840s that may have working Predrivers. If someone can tell me how to test them with just a multimeter I can see if they are any good.
 
Thought I would chime in here. I just revived a beautiful CR-840 by a thorough cleaning followed by the installion of a couple of new (aftermarket) power chips: STK-0060II.

With the guidance of folks on this forum (e.g. 4seatpilot) I have protected my delicate but still-working pre-drivers with some heat sink love... A heat sink from a video chip on an obsolete motherboard was cut in half and bonded to each chip's backside. Pre-driver temp now seems to run at about the same as the power chip ~35-39C.
 

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Where did you get the lamps !? I just got one a few weeks ago as well and I'm missing 5 lamps . I love this thing , it sounds fantastic . Yours looks really nice too .
Rudy .



Stereo Hospital can put them in or tell you were to pick them up locally, That electronics store on Park & 23rd ( Elliot's) Should carry them.:yes: I own two of these fine receivers.
 
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