Hi to everyone
My Marantz CD63 MKii stopped reading discs so I have changed the laser mech for a VAM 1202 using advice from a variety of Google searches.
Initially it played fine but after about 4 CDs it started to skip and then stopped reading the discs altogether.
I tweaked the potentiometer (again as advised on a variety of sites) and it started to play again but with intermittent skipping so I gave it another tweak and it was a bit better.
I was going to have another tweak of the pot but having read on here and elsewhere about the addition of a 10p coin to the CD clamp thought I’d try that and hey presto it now seems OK.
OK you might say well so what, “sorted”! Well my questions are:
1) if adjusting the pot adjusts the voltage to the laser, how does more weight overcome the supposedly incorrect voltage?
2) somewhere I read that additional weight is an “approved” Marantz mod to overcome skipping. Is that true?
3) does more weight on the clamp affect sound quality?
4) does more weight on the clamp cause any side effects or shorten the life of any components - I guess not if it is “approved”.
5) is it better to remove the weight (which works) and persevere with adjusting the pot?
As you might see I am new to this forum but would appreciate your thoughts/answers to these questions. And apologies for non technical terms or incorrect description but hope you get the gist!!
My Marantz CD63 MKii stopped reading discs so I have changed the laser mech for a VAM 1202 using advice from a variety of Google searches.
Initially it played fine but after about 4 CDs it started to skip and then stopped reading the discs altogether.
I tweaked the potentiometer (again as advised on a variety of sites) and it started to play again but with intermittent skipping so I gave it another tweak and it was a bit better.
I was going to have another tweak of the pot but having read on here and elsewhere about the addition of a 10p coin to the CD clamp thought I’d try that and hey presto it now seems OK.
OK you might say well so what, “sorted”! Well my questions are:
1) if adjusting the pot adjusts the voltage to the laser, how does more weight overcome the supposedly incorrect voltage?
2) somewhere I read that additional weight is an “approved” Marantz mod to overcome skipping. Is that true?
3) does more weight on the clamp affect sound quality?
4) does more weight on the clamp cause any side effects or shorten the life of any components - I guess not if it is “approved”.
5) is it better to remove the weight (which works) and persevere with adjusting the pot?
As you might see I am new to this forum but would appreciate your thoughts/answers to these questions. And apologies for non technical terms or incorrect description but hope you get the gist!!
Hi Ken and welcome to the forum!
There's a massive thread on the Marantz CD63/67 at
Marantz CD63 & CD67 mods list
which probably contains everything you ever want to know about your machine, but being so huge I appreciate it's not always easy to find the answers.
So to your specific questions:
1) Adding more weight to the clamp does nothing to the voltage, it just helps to stabilize the cd itself so the data being read by the laser is a bit more reliable, hence less skipping
2) I don't know if it was ever officially approved but it was a common 'fix' used by repair centres
3) The extra weight is felt to improve sound quality slightly for the reason above
4) I've never experienced or heard of any downsides in terms of shortened component lifespan; drive belts won't last forever but are a doddle to replace
5) Leave the weight on the clamp and don't play with the pot too much unless you've got access to a suitable oscilloscope that can show you the eye pattern and let you measure peak to peak voltage. Adjusting the pot by guesswork can lead to too high a laser voltage and that definitely will shorten the lifespan of the laser.
Another thing that causes skipping on these is a build up of old, dried out yellow grease at the ends of the metal rod the laser head tracks along and on the cogs - getting rid of this and applying a small amount of silicone based grease to re-lubricate the mech is a good idea.
Hope that helps...
There's a massive thread on the Marantz CD63/67 at
Marantz CD63 & CD67 mods list
which probably contains everything you ever want to know about your machine, but being so huge I appreciate it's not always easy to find the answers.
So to your specific questions:
1) Adding more weight to the clamp does nothing to the voltage, it just helps to stabilize the cd itself so the data being read by the laser is a bit more reliable, hence less skipping
2) I don't know if it was ever officially approved but it was a common 'fix' used by repair centres
3) The extra weight is felt to improve sound quality slightly for the reason above
4) I've never experienced or heard of any downsides in terms of shortened component lifespan; drive belts won't last forever but are a doddle to replace
5) Leave the weight on the clamp and don't play with the pot too much unless you've got access to a suitable oscilloscope that can show you the eye pattern and let you measure peak to peak voltage. Adjusting the pot by guesswork can lead to too high a laser voltage and that definitely will shorten the lifespan of the laser.
Another thing that causes skipping on these is a build up of old, dried out yellow grease at the ends of the metal rod the laser head tracks along and on the cogs - getting rid of this and applying a small amount of silicone based grease to re-lubricate the mech is a good idea.
Hope that helps...
Hello Brakspear75
Thanks for the welcome!
Yes, spot on, I’ve looked at lots of info and it is hard to see what actually relates to what you want to know if you’re not used to working on this stuff. Not exactly “wheat from chaff” but you know what I mean (I’m sure it’s all wheat!).
That said your answers hit the spot and are very welcome confirmation of what I can do.
I’ll put the pot back to where it was (I marked it!), leave the weight on (apparently a 10p coin is only 6.5grams) and check for stale grease.
Is the white Lithium grease OK or best get Silicone as you suggest.
Many thanks again, much appreciated and very helpful.
Thanks for the welcome!
Yes, spot on, I’ve looked at lots of info and it is hard to see what actually relates to what you want to know if you’re not used to working on this stuff. Not exactly “wheat from chaff” but you know what I mean (I’m sure it’s all wheat!).
That said your answers hit the spot and are very welcome confirmation of what I can do.
I’ll put the pot back to where it was (I marked it!), leave the weight on (apparently a 10p coin is only 6.5grams) and check for stale grease.
Is the white Lithium grease OK or best get Silicone as you suggest.
Many thanks again, much appreciated and very helpful.
Adjusting the pot alters the current flowing in the laser diode. Once 'lasing' action starts then a very small increase in current will cause a relatively large increase in light output.
Just altering the pot with no way of confirming what you have just done by measurement (such as monitoring the signal on an oscilloscope) is not to be advised.
Extra weight will place more stress on the small motor bearings particularly if the weight is not perfectly central.
These player/pickups are now unfortunately old, and genuine replacement parts have been out of production for many many years with the quality of generic replacements varying enormously.
I don't know where you sourced your replacement from but it might be worth you trying a part from a recognised supplier such as CPC
http://cpc.farnell.com/unbranded/vam1202-12/vam1202-12-cd-pick-up/dp/AS00207
Just altering the pot with no way of confirming what you have just done by measurement (such as monitoring the signal on an oscilloscope) is not to be advised.
Extra weight will place more stress on the small motor bearings particularly if the weight is not perfectly central.
These player/pickups are now unfortunately old, and genuine replacement parts have been out of production for many many years with the quality of generic replacements varying enormously.
I don't know where you sourced your replacement from but it might be worth you trying a part from a recognised supplier such as CPC
http://cpc.farnell.com/unbranded/vam1202-12/vam1202-12-cd-pick-up/dp/AS00207
Hi Mooly
Thanks for the CPC link. I got mine via a well known auction site from a seller with 99.8% positive feedback on over 53k transactions so “assumed” it would be OK but I was always concerned about the quality given that (I think) they are all made in China now.
I have just put the pot back to where it was originally and am about to try it again given I have also lightly lubricated the slide. I’m wondering if it was a dried grease issue as I hadn’t checked that at first.
If no joy then I will get another mech from CPC and try again - the price is favourable and I recognise them as suppliers to the trade so as you suggest quality ought to be OK.
Many thanks for the reply to my post.
Thanks for the CPC link. I got mine via a well known auction site from a seller with 99.8% positive feedback on over 53k transactions so “assumed” it would be OK but I was always concerned about the quality given that (I think) they are all made in China now.
I have just put the pot back to where it was originally and am about to try it again given I have also lightly lubricated the slide. I’m wondering if it was a dried grease issue as I hadn’t checked that at first.
If no joy then I will get another mech from CPC and try again - the price is favourable and I recognise them as suppliers to the trade so as you suggest quality ought to be OK.
Many thanks for the reply to my post.
spare supplier
Placing a 10 pence on the clamp partially solved the skipping problem in my case; no skip at the beginning but Skips more often when playing the outer tracks.
Recently bought “Original VAM1202 VAM1201 CDM12.1 CDM12.2 CD laser lens with mechanism from PHILIPS” from aliexpress.com and replacing it in the MK2 solved the problem.
Placing a 10 pence on the clamp partially solved the skipping problem in my case; no skip at the beginning but Skips more often when playing the outer tracks.
Recently bought “Original VAM1202 VAM1201 CDM12.1 CDM12.2 CD laser lens with mechanism from PHILIPS” from aliexpress.com and replacing it in the MK2 solved the problem.
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