Hi Anatech!
I measured 4,52 mm from the disc table (bottom of the rim) to the brass spacer when I first disassembled the original disc motor and I kept that value.
Because the original Motor was worn out, this value might be wrong.
I am not sure any more: I lowered the table height once but as far as I remember, I saw no difference in focus offset.
Got the fitting motor now on ebay (new), so I will experiment with it.
But I do not have a good feeling about loosing/fastening that tiny screw several times which fixes the disc table to the shaft, looks a bit fragile to me: The disc table is made from brass, so I guess the thread for the screw will not be strong...
All the best,
Salar
I measured 4,52 mm from the disc table (bottom of the rim) to the brass spacer when I first disassembled the original disc motor and I kept that value.
Because the original Motor was worn out, this value might be wrong.
I am not sure any more: I lowered the table height once but as far as I remember, I saw no difference in focus offset.
Got the fitting motor now on ebay (new), so I will experiment with it.
But I do not have a good feeling about loosing/fastening that tiny screw several times which fixes the disc table to the shaft, looks a bit fragile to me: The disc table is made from brass, so I guess the thread for the screw will not be strong...
All the best,
Salar
Now - what can this be?
VERY strange effect-
when I touch a connector chord of my Nakamichi OMS-5AII/EII, I will hear scratches in the music and the laser will even loose track.
AND - even just holding my finger very close to the connector chord (let´s say a distance about 5-1mm) has the same effect!!!
What can this be?
The 8-pin cord (JU101) connects the photo diodes of the laser (KSS-123A) with the R-F Amp (CX20109).
Touching the second connector chord (also 8 pins) which feeds the laser and coils
has no effect.
So I replaced the connector chord, but this had no effect.
Then I tried some kind of shielding: I wrapped the connector chord with copper wire and also connected the wire to the units base, but this this only detoriates the signal.
Is this normal? Can the signals from the laser be that sensitive? This does not seem logical to me, because the cord is being moved permanently by the laser.
Any advice?
All the best, Salar
VERY strange effect-
when I touch a connector chord of my Nakamichi OMS-5AII/EII, I will hear scratches in the music and the laser will even loose track.
AND - even just holding my finger very close to the connector chord (let´s say a distance about 5-1mm) has the same effect!!!
What can this be?
The 8-pin cord (JU101) connects the photo diodes of the laser (KSS-123A) with the R-F Amp (CX20109).
Touching the second connector chord (also 8 pins) which feeds the laser and coils
has no effect.
So I replaced the connector chord, but this had no effect.
Then I tried some kind of shielding: I wrapped the connector chord with copper wire and also connected the wire to the units base, but this this only detoriates the signal.
Is this normal? Can the signals from the laser be that sensitive? This does not seem logical to me, because the cord is being moved permanently by the laser.
Any advice?
All the best, Salar
Hi folks
I've a problem with the pickup unit in NAK OMS 5E.
Maybe you can help me.
I have just cleaned pickup unit and my NAK seems to be working but still it doesn't read all the cd's. I can't set the E-F Balance (VR104) so that it could work for all kinds of cd's (the VR104 function is the only thing i've tried to set so far).
What is the mechanic element holding the tray ? it doesn't close down properly (it seems to be too loose in horizontal angle).
I haven't got any service manual for this unit.
Thanks for any helps.
Regards
I've a problem with the pickup unit in NAK OMS 5E.
Maybe you can help me.
I have just cleaned pickup unit and my NAK seems to be working but still it doesn't read all the cd's. I can't set the E-F Balance (VR104) so that it could work for all kinds of cd's (the VR104 function is the only thing i've tried to set so far).
What is the mechanic element holding the tray ? it doesn't close down properly (it seems to be too loose in horizontal angle).
I haven't got any service manual for this unit.
Thanks for any helps.
Regards
Having my OMS5 serviced and
The tech says:
"The CD player is completely electronically adjusted by now and the mechanism is cleaned/lubricated/adjusted.
I am testing it now and i have two minor problems left.
The first problem arise sometime after a foward skip: the unit freeze and after a while, it start playing the choosen cut.Sometime, i have to skip back and after foward to defreeze the player.
The second problem : i am not able to go fast foward.
The problem seems to be the head suspension: it is too hard now because it is made of rubber. The rubber is dry now.
Fortunately, the player do a good job at playing cd's and i can skip back and foward.
The head signal ius very good and the disc motor too.
I have to check the servo control for the foward problem.
I have to live a little with the player to see if it will be ok."
Any suggestions for him on these remaining issues? The original problem is that the player wouldn't spin up or play, although the tray and controls seemed operational. So he's got it working mostly. Are the fast forward and next track issues related? Reading other posts, it seems like some slippage of the belt could do this as well. Any help appreciated! -CN
The tech says:
"The CD player is completely electronically adjusted by now and the mechanism is cleaned/lubricated/adjusted.
I am testing it now and i have two minor problems left.
The first problem arise sometime after a foward skip: the unit freeze and after a while, it start playing the choosen cut.Sometime, i have to skip back and after foward to defreeze the player.
The second problem : i am not able to go fast foward.
The problem seems to be the head suspension: it is too hard now because it is made of rubber. The rubber is dry now.
Fortunately, the player do a good job at playing cd's and i can skip back and foward.
The head signal ius very good and the disc motor too.
I have to check the servo control for the foward problem.
I have to live a little with the player to see if it will be ok."
Any suggestions for him on these remaining issues? The original problem is that the player wouldn't spin up or play, although the tray and controls seemed operational. So he's got it working mostly. Are the fast forward and next track issues related? Reading other posts, it seems like some slippage of the belt could do this as well. Any help appreciated! -CN
Hello chicken_neck,
mark one or mark II model? mechanically, the laser transport does not differ, except a bigger laser for Mark one and different disc motor
When jumping to the next track does not take a long time (on mark II about 5 seconds accross the whole disc) it should not be the belt.
If it is the belt, try to put some heat shrinking rubber tube on the axis of the feed motor for the laser. This might give better grip.
Marrscommunications sells belts on ebay, mainly for tabe decks. I tried belts for the OMS-5EII, mine were too thick and therefore stiff, with lesser grip, but better than a defectife belt. Try to cook the belt in hot water, then put it directly in a freezer. This might shrink the belt.
All the best,
Salar
mark one or mark II model? mechanically, the laser transport does not differ, except a bigger laser for Mark one and different disc motor
When jumping to the next track does not take a long time (on mark II about 5 seconds accross the whole disc) it should not be the belt.
If it is the belt, try to put some heat shrinking rubber tube on the axis of the feed motor for the laser. This might give better grip.
Marrscommunications sells belts on ebay, mainly for tabe decks. I tried belts for the OMS-5EII, mine were too thick and therefore stiff, with lesser grip, but better than a defectife belt. Try to cook the belt in hot water, then put it directly in a freezer. This might shrink the belt.
All the best,
Salar
Thanks, Salar
If I get it back and see that issue, I'll certainly follow the advice in this forum. Looks like there are some good deals on ebay right now for OMS series players. I'm not sure if I have the Mark I or II OMS-5
http://cgi.ebay.com/ws/eBayISAPI.dl...rms=algo=SI&its=I&itu=UCI&otn=15&po=LVI&ps=54
If I get it back and see that issue, I'll certainly follow the advice in this forum. Looks like there are some good deals on ebay right now for OMS series players. I'm not sure if I have the Mark I or II OMS-5
http://cgi.ebay.com/ws/eBayISAPI.dl...rms=algo=SI&its=I&itu=UCI&otn=15&po=LVI&ps=54
Hi Salar,
I guess better late than never ....
This is normal with almost any CD head that does not include a preamp on the head. You are causing the amplitude of teh RF signal to become diminished with high noise.
-Chris
I guess better late than never ....
Yes.
This is normal with almost any CD head that does not include a preamp on the head. You are causing the amplitude of teh RF signal to become diminished with high noise.
Exactly what I would expect. There is no fault with the cable.
Yes, expected and for the same reasons.
Yes, and yes. Remember, we are dealing with very low current signals here. You are a capacitance and antenna that injects noise and bleeds signal.
Yes. Don't do anything and don't touch that wire group as the machine plays. Replacing the covers would solve that.
-Chris
Hi vonolof,
-Chris
The very first thing you always need to do is look at the eye pattern on the RF test point. Return that control to it's original position. Those original NEC single beam heads are wonderful, but it may be near end of life for it. You will need to compare the laser current draw to the value printed on the head. You are allowed 10% over that printed value.
Is it the arm that is loose, or the tray. The clamping system is magnetic I think on these. The arm should not have any horizontal play, but the puck completely disconnects from the arm if it's a magnetic clamp.
Oh, oh.... Not good at all. The manual for the OMS-7E (E = European model) will also be good for you. You really need the service manual. You should not have touched anything at all without the manual. Be advised that this machine is both complicated and very good. The optical block has adjustments in every plane that are exact. Please read my previous posts on this subject.
-Chris
Hi chicken_neck,
My fear is growing ...
Feeling of impending disaster is taking root ...
Fear man, just plain fear!
This would have been seen in the adjustment of the electronic servos. Do you know if this technician was authorized warranty for Nakamichi, or is he a TV technician?
We need to know if you have an OMS-5 or OMS-5II. These are totally different machines, as Salar pointed out.
However, on this point there are differences :
-Chris
I am beginning to be afraid.
That is either the feed belt or mis-adjusted servos. Did your machine have this fault to begin with?
My fear is growing ...
Same deal!
Feeling of impending disaster is taking root ...
Ahh, come on!! Looking at the eye pattern would show this if it were true. I have never seen a bad suspension in an OMS 5 or 7 head. The type II machines, yes.
Fear man, just plain fear!
This would have been seen in the adjustment of the electronic servos. Do you know if this technician was authorized warranty for Nakamichi, or is he a TV technician?
Yes, they most certainly are!, in most cases anyway. Salar has given you good advice on this topic.
We need to know if you have an OMS-5 or OMS-5II. These are totally different machines, as Salar pointed out.
However, on this point there are differences :
The type I has a completely adjustable head in all planes. The type II has very few adjustments. The type I head is a single beam system, the type II is a three beam head. The servos are completely different, as is the chip set.
All these machines will be suffering from age related issues. Plan on this for cosmetic parts, or mechanical tray parts in case you break yours.
-Chris
Are any other Nakamichi OMS Players good as transport ?
To Chris & all,
wanted to inquire whether the other OMS Players from Nakamichi are any good ? Chris had pointed out the ruggedness of the transport mechanism (die-cast aluminium) of the OMS-5
What about the OMS-3, OMS-4 or OMS-2a ? They appear to be more widely available, also in europe. There is yet another CD-Player from Nakamichi - the CD-4 (always wondered why it doesn't share the "OMS" designation). What Pickup/Laser do they use ? Tthe OMS-5/7 appear to house the KSS-151A from Sony...
What about replacement parts ? Can the important replacement parts for the Nakamichis still be obtained (belts, lasers, pickup) ? I know the DAC portion isn't up to modern standards. I plan to get it modded with another DAC, a Digital Output connection, a clock upgrade and a good output stage (such as the ZAPfilter or something similar)
best rgrds
CROSSY
To Chris & all,
wanted to inquire whether the other OMS Players from Nakamichi are any good ? Chris had pointed out the ruggedness of the transport mechanism (die-cast aluminium) of the OMS-5
What about the OMS-3, OMS-4 or OMS-2a ? They appear to be more widely available, also in europe. There is yet another CD-Player from Nakamichi - the CD-4 (always wondered why it doesn't share the "OMS" designation). What Pickup/Laser do they use ? Tthe OMS-5/7 appear to house the KSS-151A from Sony...
What about replacement parts ? Can the important replacement parts for the Nakamichis still be obtained (belts, lasers, pickup) ? I know the DAC portion isn't up to modern standards. I plan to get it modded with another DAC, a Digital Output connection, a clock upgrade and a good output stage (such as the ZAPfilter or something similar)
best rgrds
CROSSY
Hello,
I live in France, sorry for my english,
I have an Nakamichi OMS-5 cd player , unfortunatly does not read 8 years ago. Now, i should like to repear it.
In first, how i can see that the laser pick-up is not good ?
The belt is no good an i replace it with an elastic but i suppose it is not for that.
I read that a member SALAR if he can send me the service manual, he write to a member :"I can mail you the service manual, if you like. (16MB) Then you can judge if you like to do the work...if you like. (16MB) Then you can judge if you like to do the work..."
I try to send an email but it necessary that i have many posts.
Best regrets
I live in France, sorry for my english,
I have an Nakamichi OMS-5 cd player , unfortunatly does not read 8 years ago. Now, i should like to repear it.
In first, how i can see that the laser pick-up is not good ?
The belt is no good an i replace it with an elastic but i suppose it is not for that.
I read that a member SALAR if he can send me the service manual, he write to a member :"I can mail you the service manual, if you like. (16MB) Then you can judge if you like to do the work...if you like. (16MB) Then you can judge if you like to do the work..."
I try to send an email but it necessary that i have many posts.
Best regrets
Nakamichi
Wow -
this table of Transport / DACs is really usable - a great pointer ! Not just for Nakamichi players... (One I was always curious about is not included however - the Luxman D-600s)
well, turns out that the OMS series might be not be worth pursuing. Nice transport but no digital out - the most important feature if you want to use a CD-player as a pure transport !
Turns out a friend of mine got a CD-4 and gave it to me ... I already obtained a service manual. It's in great shape and working condition (for years behind a glass shelve and the guy) but I guess I'm going to sell it ... uses a SONY laser and I read spare parts are still available.
anyway,
thank you very much !
CROSSY
Wow -
this table of Transport / DACs is really usable - a great pointer ! Not just for Nakamichi players... (One I was always curious about is not included however - the Luxman D-600s)
well, turns out that the OMS series might be not be worth pursuing. Nice transport but no digital out - the most important feature if you want to use a CD-player as a pure transport !
Turns out a friend of mine got a CD-4 and gave it to me ... I already obtained a service manual. It's in great shape and working condition (for years behind a glass shelve and the guy) but I guess I'm going to sell it ... uses a SONY laser and I read spare parts are still available.
anyway,
thank you very much !
CROSSY
Hi Crossy,
well, I built a digital out with the help from members of this forum
for the OMS-5/7II (Mark II Models):
Thread
KSS-123A replacement lasers are not easy to find and expensive, belts are still available via Marrscommunications, spindle motor
(Mabuchi RF-310T-11400) are also still available, but have longer shafts.
Again, I am talking about OMS-5/7 MarkII replacements.
But unfotunatelay, except the belts, there will be not replacement parts for
the Philips based Mark I models...
All te best,
Sal
well, I built a digital out with the help from members of this forum
for the OMS-5/7II (Mark II Models):
Thread
KSS-123A replacement lasers are not easy to find and expensive, belts are still available via Marrscommunications, spindle motor
(Mabuchi RF-310T-11400) are also still available, but have longer shafts.
Again, I am talking about OMS-5/7 MarkII replacements.
But unfotunatelay, except the belts, there will be not replacement parts for
the Philips based Mark I models...
All te best,
Sal
Nakamichi OMS 5.
hello,
Thank you Solar for the Nakamichi OMS5 manual.
I read it, replacement laser is not easy and to difficult for me.
Today, I can see that the CD don't turn fast, I don't know why. Perhaps, somedy know this problem because the OMS5 always eject the CD, it can't read it.
I don't speak a good english and it is difficult for me reading the post.
hello,
Thank you Solar for the Nakamichi OMS5 manual.
I read it, replacement laser is not easy and to difficult for me.
Today, I can see that the CD don't turn fast, I don't know why. Perhaps, somedy know this problem because the OMS5 always eject the CD, it can't read it.
I don't speak a good english and it is difficult for me reading the post.
Sorry to bump an old thread but I just dug my OMS-5 out of the closet again and for the life of me, I can't find the belt that everyone is talking about. My player has the no-read spit out disc problem that seems to be fixed with a new belt but having removed both covers, I still can't find it!
I too have dug mine out of the closet in hopes of getting it running again. It's problem seems to be with the speed control as the disc spins way!! too fast. When the player gives up trying to read it it spits it out still spinning like mad.
I did the mod for the OMS7 but now I can't find the service manual as I think the speed control cct may be similar if not the same.
Any thoughts?
I did the mod for the OMS7 but now I can't find the service manual as I think the speed control cct may be similar if not the same.
Any thoughts?
Why old? There you go:
Part 11 is the belt. New belts are sold from "Marsscommunications".
All the best,
Sal
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An externally hosted image should be here but it was not working when we last tested it.
Part 11 is the belt. New belts are sold from "Marsscommunications".
All the best,
Sal
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Thank you very much for the scans, but as has happened in the past and will likely happen again, I put the OMS5 on the bench and while brandishing a screwdriver we had a little staring match. I was pretty sure it blinked first so I tried another disc before I disassembled it, and lo and behold... it worked. I am pleased to say that it has been singing beautifully since. I always like it when I can intimidate a piece of gear to work properly.
Thank you again for the scans.
Thank you again for the scans.