I have had a Krell KAV-250CD player (coupled with a KAVP/A combination) for nearly 14years. In that time I have had a few problems with the player reading certain discs, either not finding the TOC or not being able to play the disc even after the TOC has been located. It has never been able to read copies. Over the past few months this seems to have got worse. Having scanned the web I think it must be a Mk1 unit; I'm not sure about the transport mechanism but it certainly has a Sanyo SF P1 laser head.
I'm wondering whether it is possible to replace the mechansm with something a little more reliable/robust. Does anyone have any advice or experience of this? I does look as though its a fairly common problem with this unit. I'd prefer not to have to replace the whole unit if at all possible.
Any advice would be greatly appreciated
I'm wondering whether it is possible to replace the mechansm with something a little more reliable/robust. Does anyone have any advice or experience of this? I does look as though its a fairly common problem with this unit. I'd prefer not to have to replace the whole unit if at all possible.
Any advice would be greatly appreciated
check out this threads:
http://www.diyaudio.com/forums/digi...a-classe-cdp-3-roksan-caspian-main-board.html
http://www.diyaudio.com/forums/digi...-cdp-cec-2100-3100-service-manual-wanted.html
because the same CEC-Sanyo parts are also in use in the listed models there, maybe you will find by this model numbers the right informations.
http://www.diyaudio.com/forums/digi...a-classe-cdp-3-roksan-caspian-main-board.html
http://www.diyaudio.com/forums/digi...-cdp-cec-2100-3100-service-manual-wanted.html
because the same CEC-Sanyo parts are also in use in the listed models there, maybe you will find by this model numbers the right informations.
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Many thanks tiefbassuebertr,
I saw these the other day but will follow up more closely. If anyone has specific experience of changing the mechanism in the Krell, I'd love to hear about it.
I saw these the other day but will follow up more closely. If anyone has specific experience of changing the mechanism in the Krell, I'd love to hear about it.
The SF-P1 is one of the most reliable lasers ever made for cd. Your problems are almost 100% certainly due to tracking drive mech or alignment issues. Most common with these is broken teeth on drive gears, but could be just a lubrication problem, if it's not simply misalignment of servos, laser power, etc.
I agree.
The best solution for troubleshooting is the purchase of a used CEC2100 or CEC3100 (CD2100, CD3100).
By exchange and cross-comparison of the loader, optical pick-up and main-PCB you will find quickly the main reason for the observed unwanted effects.
check also the attachments and this URLs:
https://sites.google.com/a/lvsystem.ru/lab/praktika/audio/upgrage-cec-2100
so as post #19 about
http://www.diyaudio.com/forums/digi...classe-cdp-3-roksan-caspian-main-board-2.html
for the adjustment hints.
Attachments
Thanks for the replies. Having played with the unit for the past few days, including thorough clean of the lens, rails etc. I'm convinced it is a tracking problem. Using a little 'gentle force' I can get the unit to pick up some of my troublesome disks but as yet have not worked out a way to adjust the tracking. All the gears/teeth etc. look fine.
That confirms absolutely that it is not a laser problem. Have you lubricated the laser sled guide rails? The way to test for a lub issue is to remove the one of the tracking drive gears to allow the laser to move freely. If you feel any resistance when manually sliding the sled back & forth, you just need to lub. You should use a fairly thin silicone grease, properly, but can get away with a light petro-based grease, which you can also apply to the shafts of the driver gears. You should NOT change any adjustment trimpots on the boards without knowing exactly what you're doing, and it is extremely rare for an SF-P1 to drift to where it should need any such adjustments in any case.
Krell 250CD Laser Replacement
Hello,
As you can see from the earlier post I had a similar problem with a Krell 250CD (I assume an earlier model than yours). After much playing around and despite the comments received on the forum I finally 'bit the bullet' and bought a replacement laser block which in my case was a Sanyo SFP1 (cost about £45). When it arrived I noticed it was somewhat more substantial than the very plastic version in my unit. It was pretty easy to replace and when connected the laser was visibly brighter, of course I'm not advocating looking down a laser but the effect was very obvious. I did clean the rails etc. during the replacement but I had done that before (many times!). In a nutshell the result was spectacular and since then my old Krell, now over 20 years old, has hardly missed a beat in the 3 years since I replaced the laser. Indeed it will now play copied CDs which the old laser would never do. I did notice that the cables with the new unit were heavier and I was worried that this would hinder tracking i.e. dragging the head back slightly. I recently changed a drive belt and then did have tracking problems which I resolved by moving the laser cables a little.
I appreciate my model is different to yours but I guess my message is that despite all advice about the laser not being the issue, a simple and inexpensive replacement solved my problem. Best wishes. Mark
Hello,
As you can see from the earlier post I had a similar problem with a Krell 250CD (I assume an earlier model than yours). After much playing around and despite the comments received on the forum I finally 'bit the bullet' and bought a replacement laser block which in my case was a Sanyo SFP1 (cost about £45). When it arrived I noticed it was somewhat more substantial than the very plastic version in my unit. It was pretty easy to replace and when connected the laser was visibly brighter, of course I'm not advocating looking down a laser but the effect was very obvious. I did clean the rails etc. during the replacement but I had done that before (many times!). In a nutshell the result was spectacular and since then my old Krell, now over 20 years old, has hardly missed a beat in the 3 years since I replaced the laser. Indeed it will now play copied CDs which the old laser would never do. I did notice that the cables with the new unit were heavier and I was worried that this would hinder tracking i.e. dragging the head back slightly. I recently changed a drive belt and then did have tracking problems which I resolved by moving the laser cables a little.
I appreciate my model is different to yours but I guess my message is that despite all advice about the laser not being the issue, a simple and inexpensive replacement solved my problem. Best wishes. Mark
Trouble with KAV-250cd
I've got a Krell KAV-250cd which is no longer working. Lately it has developed a few problems. I think I've resolved the mechanical problems, but have an electrical problem.
On start-up (or closing the cd transport) it will attempt to read the TOC (Table of Contents), but only displays " 0 0:00" on the front panel. With the scope on Gnd (TP19) and HF (TP16), I get the following eye pattern for about 10 seconds while the cd is spinning. Is this a normal eye pattern while trying to read the TOC???
I've got a Krell KAV-250cd which is no longer working. Lately it has developed a few problems. I think I've resolved the mechanical problems, but have an electrical problem.
On start-up (or closing the cd transport) it will attempt to read the TOC (Table of Contents), but only displays " 0 0:00" on the front panel. With the scope on Gnd (TP19) and HF (TP16), I get the following eye pattern for about 10 seconds while the cd is spinning. Is this a normal eye pattern while trying to read the TOC???
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