I bought recently second hand KAV250CD mk2, which works very well.
I cleaned the lens using a standard cleaning comercial CD cleaner, and almost immediately after that, I noticed sometimes the CD skips, no matter if it is new or old, printed or recorded.
This made a suspicion to me, that maybe I should change the pickup (or anyway to have one to spare), but I cannot find any information which model is. Asked Krell support, but they (as expected) are sugesting to buy from them, for 200$.
Does anybody have this kind of experience, and does it anybody know which laser pickup unit is inside this model?
Any input appreciated
I cleaned the lens using a standard cleaning comercial CD cleaner, and almost immediately after that, I noticed sometimes the CD skips, no matter if it is new or old, printed or recorded.
This made a suspicion to me, that maybe I should change the pickup (or anyway to have one to spare), but I cannot find any information which model is. Asked Krell support, but they (as expected) are sugesting to buy from them, for 200$.
Does anybody have this kind of experience, and does it anybody know which laser pickup unit is inside this model?
Any input appreciated
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Hm...I don't think so, according to some internal pictures, it seems like some of the VRDS/TEAC transport in KAV 300CD
the transport mech is teac vrds cmk4. laser unit is kss-213. i dare to bet to my last dollar on this one. why? because i have this player, and i have done replacement of laser pickup for it.
Confirm CMK4 but I beg to differ on the laser pickup. The laser unit is the KSS240A. I also have the KAV300CD and have just replaced the 2-step tray gear and also adjusted the focus and tracking gains. (see TEAC vrds T1 gear broken thread) Unless of course the laser unit used is dependent on mod number.the transport mech is teac vrds cmk4. laser unit is kss-213. i dare to bet to my last dollar on this one. why? because i have this player, and i have done replacement of laser pickup for it.
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If it is a Sony pickup the lens suspension has probably failed, you usually can tell this if the lens is sagging in the pick up assembly. I have managed to save a few by heating it in a low temperature (inverted) for a few hours and normalizing the temperature slowly. This might work but not always.
Jam
Jam
Problem with Krell KAV250cd
I have a Krell KAV250cd with a few issues. I believe I've resolved the mechanical issues and now am working on the electrical issues.
Then the transport starts-up (or cd is loaded in the transport - Open/Close button), the transport will attempt to read the TOC (Table of Contents) for about 10 seconds. When I connect my scope between GND (TP19) and HF (TP16), I get the following eye pattern on the scope during that 10 second period. Is this a normal eye pattern while trying to read the TOC???
I have a Krell KAV250cd with a few issues. I believe I've resolved the mechanical issues and now am working on the electrical issues.
Then the transport starts-up (or cd is loaded in the transport - Open/Close button), the transport will attempt to read the TOC (Table of Contents) for about 10 seconds. When I connect my scope between GND (TP19) and HF (TP16), I get the following eye pattern on the scope during that 10 second period. Is this a normal eye pattern while trying to read the TOC???
Attachments
I have a Denon DCM-320 5-disc CD changer which has exactly the same symptom:
Focus search is successful
Disc rotates at normal speed
TOC is read and displayed in front panel display
RF signal is at correct amplitude for this machine (1.0-1.2V P-P)
Eye pattern looks excellent for several seconds.
Then: RF level drops to 1/2 amplitude and gets very noisy.
The disc never starts to play.
This turned out to be a faulty CCA1372S servo IC. This is an unusual fault. IC chips don’t fail very often.
More details of my unit are in this thread:
Sony CDP790 and KSS240 Restoration Project
Finally, I am appalled that so much ultra-high-end mega-$$$-priced audio gear is totally unsupported by the manufacturer. Especially after it is several years of age. Pardon me but I’ll stick with vintage audio gear where I can find 10 units for $2 each at garage sales and move parts around to create 5 or 6 units which work perfectly.
@electricboyo
Just to play Devil's advocate....
You cannot just blame the ''ultra-high-end mega-$$$-priced audio gear'' Manufacturers for no longer supporting their gear after many years.
I very much doubt your Denon CD Player will still be officially 'covered' by Denon.
Denon didn't make any of their own Lasers so 'bought in' all their Mechanisms from mostly SONY if I remember correctly.
Most of the Lasers from the period of your Denon are now no longer made. I think your Denon used the KSS-240A and this hasn't been made by SONY for a very long time.
So not even even SONY can now 'support' any of their own Players which used this or any of their other Lasers from this period.
So all the Manufacturers who used these SONY lasers can themselves no longer support these Players because the most common part to fail is no longer made, only Chinese copies now available which no Manufacturer could use and give a Warranty on the repair.
Your argument to stick to Vintage gear as you can buy lots of cheap whole units to keep them going can also be applied to the ''ultra-high-end mega-$$$-priced audio gear''.
The KRELL in this thread uses some other Manufacturers laser as KRELL never made their own. So find the relevent dodnor unit which the KRELL was based on (SONY/SANYO?) and buy a few of them. You keep your KRELL up and running.
P.
Just to play Devil's advocate....
You cannot just blame the ''ultra-high-end mega-$$$-priced audio gear'' Manufacturers for no longer supporting their gear after many years.
I very much doubt your Denon CD Player will still be officially 'covered' by Denon.
Denon didn't make any of their own Lasers so 'bought in' all their Mechanisms from mostly SONY if I remember correctly.
Most of the Lasers from the period of your Denon are now no longer made. I think your Denon used the KSS-240A and this hasn't been made by SONY for a very long time.
So not even even SONY can now 'support' any of their own Players which used this or any of their other Lasers from this period.
So all the Manufacturers who used these SONY lasers can themselves no longer support these Players because the most common part to fail is no longer made, only Chinese copies now available which no Manufacturer could use and give a Warranty on the repair.
Your argument to stick to Vintage gear as you can buy lots of cheap whole units to keep them going can also be applied to the ''ultra-high-end mega-$$$-priced audio gear''.
The KRELL in this thread uses some other Manufacturers laser as KRELL never made their own. So find the relevent dodnor unit which the KRELL was based on (SONY/SANYO?) and buy a few of them. You keep your KRELL up and running.
P.
Firstly, which model of KAC250CD is in the question? The first run or Mk2?
As I started this topic a few years a go, maybe I can help you
-if it is the first production run, a "normal" KAV250CD - then the transport/laser mechanism is of Sanyo type, so frequently prone to failure, that Krell decided to change this on Mk2 model. Bonus on that model was DAC-analog stage chopped down from KAV-300CD, whole discrete instead a op amp.
-the KAV250CD/2 series uses Phillips so called - Short Loader mk3, and both of them seems to be unavailable as a new units.
I resolved all issues simply transplanting the Short loader mk3 derived from several Philips/Marantz low end CD players which can be found for 20-30$ for the whole unit. Some of the models are Philips CD-753 and Marantz CD-4000. OK, I've done it twice, sinc ethe first unit was also with quirks, but that was acceptable risk, so I've ordered another 753. CD 752 (or 751, a step down from753) is the same transport but they cannot read recorded disk, only pre-recorded.
The whole "transplantation" procedure is simple, but do not unglue the front metal cover on Krell, but remove the whole ladder and put it back on the new mechanism. In service manual for CD-753 everything is explained. Otherwise, you do need to reglue the front cover of the ladder, which is additional and unneccessery job.
But, if the mechanism is Sanyo, then I don't know how to do it and which models may serve as a donor.
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For more than 10 years third-party generic “aftermarket” KSS-240A, KSS-210A, and KSS-213A optical pickups have been readily available. I recently purchased some of these “generic” KSS-series optical pickups because I was curious to learn whether or not they were functional. I didn’t expect much because they cost only $11 USD each. I was pleasantly surprised to find that they perform as well (or better) than original Sony-made optical pickups.
Excellent suggestion. This is an option for many vintage high-end and “limited production” disc players.
The biggest complaint I have about the “high-end” audio brands is that they rarely published service manuals or even basic schematics. They didn’t provide repair parts either. Most of these units could only be repaired by sending them back to the manufacturer. And even that was limited to units which were only a few years of age.
In contrast some (not all) mid-range audio manufacturers have gone out of their way to provide customer support.
Example: Onkyo.
During the 2008-2014 time frame major semiconductor manufacturer Texas Instruments (TI) had a huge issue with faulty DSP IC chips which were used in many brands of home theater receivers. These tended to fail after the manufacturer’s warranty expired. But Onkyo offered free replacement of the digital PC board to all owners of affected products, regardless of in-warranty status. One didn’t even need to be the original purchaser. My son had an Onkyo A/V receiver purchased from Craigslist which developed the DSP fault. Onkyo sent a prepaid shipping carton to us, replaced the digital PC board, and shipped it back to us, all free of charge. That unit is still working perfectly more than 3 years later.
-EB
I never argued this point, but a Manufacturer cannot fit these generic Lasers themselves and offer repair with a Warranty. And they cannot supply these Lasers.
The 'Originals' haven't been available for years.
The chances are that if they bought in the Mechanisms from SONY/Philips/SANYO that's all they bought or were allowed to buy.
They may not have been allowed to buy the Schematics (?).
They bought enough Mech's to make some Players and enough spares to cover the Warranty period in case of repairs (I think by Law they had to keep Spares for 5 Years (?)).
Most would offer Spare Parts but who would fit them? How many KRELL Dealers in the UK had a Service Dept?
I have just been helped greatly by a MAJOR high End US based Audio Brand in repairing one of their Transports and DACs.
They could not have been more helpful in getting a 25 year old bit of kit going again.
The end user was over the moon and will continue to support the Brand.
I agree though, not all are like this.
AND, some of the Low/Mid-fi Brands I have had to deal with over a 30+ year career in repairing this stuff have been an absolute joke with respect to helping 'their' customers.
You cannot lump everyone together. There are some good and bad in all the price ranges.
P.
Hi Guys,
Thank you for your suggestions. Just a bit more background information. I bought the KAV250cd new back in 1999. It is the original versions not the updated version - mk2.
I cleaned the transport and replaced the Sanyo SF-P1 laser head assembly. (The replacement head assembly is made of metal where the original version was plastic.) I also replaced the drive belt.
I tested the transport motor(s) and have pretty much constant resistance (using a DVM) while rotating the drive shaft. I even connected an external low voltage power supply to the motors through a 22 ohm resistor and connected my scope across motor leads. The wave pattern was constant thus I assume there are no bad commutator spots in either motor. The plastic gears are all in good condition and lubricated them with silicone lubricant. (Incidentally, one has to be careful in using silicone lubricants on plastic parts. Some silicone lubricants actually attack plastics.) The transport assembly runs very smoothly.
I used the C.E.C./Sanyo adjustment procedures found elsewhere on this forum. (The circuit board is 4B10018600A) The diodes and transistors appear to be ok.
I still have the original problem of not being able to read the TOC (Table of Contents), and of course not being able to play music. At this point, I'm thinking I might have a defective integrated circuit. I'll play around with it some more this week and see if I can find any other prospective problem areas...
Keith
Thank you for your suggestions. Just a bit more background information. I bought the KAV250cd new back in 1999. It is the original versions not the updated version - mk2.
I cleaned the transport and replaced the Sanyo SF-P1 laser head assembly. (The replacement head assembly is made of metal where the original version was plastic.) I also replaced the drive belt.
I tested the transport motor(s) and have pretty much constant resistance (using a DVM) while rotating the drive shaft. I even connected an external low voltage power supply to the motors through a 22 ohm resistor and connected my scope across motor leads. The wave pattern was constant thus I assume there are no bad commutator spots in either motor. The plastic gears are all in good condition and lubricated them with silicone lubricant. (Incidentally, one has to be careful in using silicone lubricants on plastic parts. Some silicone lubricants actually attack plastics.) The transport assembly runs very smoothly.
I used the C.E.C./Sanyo adjustment procedures found elsewhere on this forum. (The circuit board is 4B10018600A) The diodes and transistors appear to be ok.
I still have the original problem of not being able to read the TOC (Table of Contents), and of course not being able to play music. At this point, I'm thinking I might have a defective integrated circuit. I'll play around with it some more this week and see if I can find any other prospective problem areas...
Keith
Does the Laser go to Home Base at the start though.
If you replaced the Laser with a metal bodied one then this is the SF-91. This comes with much stiffer Leads attached and this may be preventing the smooth movement of the Laser and even preventing it from physically being able to reach Home Base, or if it can with the higher Voltage applied to the Motor to get it there, once that Voltrage disappears and 'normal running voltage' is applied, the stiff Leads may be pulling it away from the TOC area and hence the eye pattern you showed.
P.
If you replaced the Laser with a metal bodied one then this is the SF-91. This comes with much stiffer Leads attached and this may be preventing the smooth movement of the Laser and even preventing it from physically being able to reach Home Base, or if it can with the higher Voltage applied to the Motor to get it there, once that Voltrage disappears and 'normal running voltage' is applied, the stiff Leads may be pulling it away from the TOC area and hence the eye pattern you showed.
P.