Forums - Help with CSP3

kulafu Seasoned Member Posts: 272	Help with CSP3 10/25/25 at 14:26:02 One of my CSP3 stopped working. All tubes light up but no sound comes out. Swapped all tubes and still no sound. I have isolated it to just this CSP since my second CSP3 works on the same system. Before I contact DECWARE, I was just looking to see if anyone can provide some troubleshooting advice. Bob
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JHC

Senior Member

Posts: 70

Re: Help with CSP3
Reply #1 - 10/25/25 at 14:49:03

You might have blown one of the rectifier fuses. If you open the bottom there are three fuses near the rectifier socket. They are easy to pop out, but it might be hard to see if they have been blown. You can get fuses on Amazon or a local electronics store for very cheap so definitely worth getting some and testing it out. CAJames pointed me to ceramic fuses which I now use and have been great (also very cheap).

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Sumiko Starling > VPI Signature Classic > Aric Audio Super MC/MM > Pine Tree Audio 67+ > SE84UFO x2 balanced monos > Omega CAMs

Reference Music: F♯A♯∞, Life Metal, Nirvana Unplugged, Timewave Zero, Nebraska, Pastel Blues

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kulafu Seasoned Member Posts: 272	Re: Help with CSP3 Reply #2 - 10/25/25 at 14:53:25 JHC, Thanks! Do you the rating of these fuses? Bob
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JHC

Senior Member

Posts: 70

Re: Help with CSP3
Reply #3 - 10/25/25 at 15:26:27

There are three total fuses and two different kinds. The one that has blown on me was 200mA. I picked up a 10-pack of "MECCANIXITY 5x20mm Ceramic Fuse 250V Slow Blow" fuses for under $10 on Amazon. I am sure there are better fuses out there, but that is maybe the one audiophile rabbit hole I refuse to go down. I ended up replacing both of the 200mA fuses. I can't remember what the other fuse is, maybe 5A, but I left that. Regardless, all of the fuses should have their values on the fuse endcaps.

I have blown the rectifier fuse twice, the first time it was clearly blown, the second time I couldn't really tell from the fuse itself, but after replacing them everything fired up and worked as it should. And both times all of the tubes, even the rectifier lit up (even when the rectifier arced).

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Sumiko Starling > VPI Signature Classic > Aric Audio Super MC/MM > Pine Tree Audio 67+ > SE84UFO x2 balanced monos > Omega CAMs

Reference Music: F♯A♯∞, Life Metal, Nirvana Unplugged, Timewave Zero, Nebraska, Pastel Blues

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JHC Senior Member Posts: 70	Re: Help with CSP3 Reply #4 - 10/25/25 at 15:46:05 PS my amps are SE84UFOs. Not sure if they have the same rectifier fuse values. Likely, but it's worth double checking.
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MikeinMontana

Seasoned Member

Posts: 344

Re: Help with CSP3
Reply #5 - 10/25/25 at 19:47:41

Same here, SE84UFO2.1, 200mA slowblow. The rectifier AND that fuse blew in my case. Some time ago now and all has been perfect since 2 replacements.. The original rectifier looked as if it was working though/ lit up like usual....but a no go until replaced. The second rectifier quickly had lights out, fuse fine that time...lol. Hopefully it is just a fuse. I will not use a Chinese tube in my amp. Some love them and that's all good. Choices. Smiley

Good luck, sounds like an easy fix. These folks here and Decware helped me out on the same situation. Awesome folks! All the best ~ Mike

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_MG_1907r-2_002.jpg

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kulafu Seasoned Member Posts: 272	Re: Help with CSP3 Reply #6 - 10/27/25 at 12:38:35 Thanks! Will call DECWARE and get specs for all three fuses. The fuses were definitely blown. Bob
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RPEPPER

Verified Member

Posts: 30

Re: Help with CSP3
Reply #7 - 10/27/25 at 20:06:42

Bob,

Please post what you find out about the fuses.

I had a similar problem. I recently purchased a used CSP3 and I absolutely love the difference it makes. BUT (there's always a BUT) when I initially hooked it up, it powered up, tubes lit up and NO sound. To make a long story short the rectifier tube that came with it had blown as did the fuses. The fuses looked fine but I replaced then anyways. I installed the rectifier that I planned on using anyways. VOILA

I want to have the correct fuses on hand if there is a future problem.

FYI - Lon coached me though this!

Thanks

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mrchipster

Seasoned Member

Posts: 113

Re: Help with CSP3
Reply #8 - 10/27/25 at 22:13:12

Never a bad idea to contact Decware to get the correct info from the horse's mouth so to speak. Here are a couple of pictures of the inside of my CSP3 with full 25'th anniversary mods. As JHC points out, they are 5x20mm and 2 x 200mA, 1 x 5A. The fuse board shows 6A and 1/4A (250mA) which is the max, but I think 200mA and 5A are used. The fuse in the IEC outlet is 3A. The picture on the website for the CSP3 doesn't show any fuses so not sure if fuses are a part of the 25'th mods, or if the design changed since the picture to include fuses now, but for what it's worth:

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SE84UFO25 - CSP3 (A-mods)
ZROCK2 (A-mods) - ZBIT
Cambridge Audio CXN V2 (ModWright)
Cambridge Audio CXC
Carver C-9
Zu Audio Soul Supremes
VIABLUE IC's & Spkr cables ; DSR3 IC's
Audio-Technica TT

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Lon Seasoned Member "Love without guts is worthless!" Philip K. Dick Posts: 26977	Re: Help with CSP3 Reply #9 - 10/27/25 at 23:50:29 I'm pretty certain fuses are there regardless of mods or no mods. Glad you are up and running again!
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