Just want to share my experience in lovely OMS-5 repairing. Some time ago I noticed occasional sound interruptions. Discs and tracks have been recognized without any problems. When I tried to recline and put the player on the side the sound distorted more and finally cut out. Looked like there is some tension in spindle shaft and error recovery system can't recover. And I was right! So I took out the spindle motor and put a small drop of good oil on the shaft between round plate and bearing sleeve. I used a toothpick for this operation 
Now it plays like a charm! I believe original oil been degraded over the years.
Good lack to all!
Now it plays like a charm! I believe original oil been degraded over the years.
Good lack to all!
Thanks for reply
Don't you think "fine mechanism grease" may get clogged as well? Original grease became a black sticky mass like a caoutchouc.
OMS 5A mkII
Hi everybody reding this Thread.
I own a OMS 5A mkII cd player (more than 20 years old and never repaired) and I love its sound.
I've been reading this thread recently for a while and want to share a new problem I have with this venerable Nak:
Reading a complete cd from 1 to n tracks in order and without interruptions its ok, but if you want to change or skip the last tracks (usually from track 11 and beyond) the player goes slow reaching the track and seems not to find the track at all (going back to a lower number track usually solve this and the nak returns to normal operation).
Im thinking in changing the belts (I saw in ebay a guy selling this) but I'm not shure about the problem.
I will appreciate if someone have the service manual and it's possible to share with me, or bring me some advice with this trouble.
Hi everybody reding this Thread.
I own a OMS 5A mkII cd player (more than 20 years old and never repaired) and I love its sound.
I've been reading this thread recently for a while and want to share a new problem I have with this venerable Nak:
Reading a complete cd from 1 to n tracks in order and without interruptions its ok, but if you want to change or skip the last tracks (usually from track 11 and beyond) the player goes slow reaching the track and seems not to find the track at all (going back to a lower number track usually solve this and the nak returns to normal operation).
Im thinking in changing the belts (I saw in ebay a guy selling this) but I'm not shure about the problem.
I will appreciate if someone have the service manual and it's possible to share with me, or bring me some advice with this trouble.
BTW, who sells spare parts-worldwide?
Nakamichi doesn´t.
Bowers&Wilkins (no, not the loudspeaker company) are one company.
welcome to Bowers & Wilkins uk the home of hi-fi
Any other company?
B&W did send me one spare (tray´s front panel) but it got lost by german postal sevice. This front panel was the last spare part they had.
Maybe I can find it in the U.S. or Japan?
Nakamichi doesn´t.
Bowers&Wilkins (no, not the loudspeaker company) are one company.
welcome to Bowers & Wilkins uk the home of hi-fi
Any other company?
B&W did send me one spare (tray´s front panel) but it got lost by german postal sevice. This front panel was the last spare part they had.
Maybe I can find it in the U.S. or Japan?
Ok, the new belt is fitted (pretty tight fit i'd say), and...
Now i have another problem - it takes the disc, spins it for several seconds (10-12sec) and then spits it back.
How do i know whether the belt is too tight or there are other issues? (laser pickup gone)
Could the CD spin speed be too slow? I have to compare it with other player...
Hm... at least 3 failures in single unit
Now i have another problem - it takes the disc, spins it for several seconds (10-12sec) and then spits it back.
How do i know whether the belt is too tight or there are other issues? (laser pickup gone)
Could the CD spin speed be too slow? I have to compare it with other player...
Hm... at least 3 failures in single unit
Unless you actually mean you need a power transformer for the player, or the supply board got horribly damaged, there is no chance you need an entire power supply. On the original OMS-5/7, power supply issues ALWAYS, in my rather large amount of experience with them, come down to either cracked solder joints on the supply board, especially on the heatsink-mounted regulators, or failed regulator IC's, usually one of the 7805 type +5V regs. I've seen exactly nothing else go wrong in these supplies, and never a bad power transformer. If you do, somehow, have a bad transformer, your only chance is a cheap enough purchase of another OMS-5 with a bad laser, which is not that uncommon.
more re. OMS-5 power supply
Thanks stephensank, just saw your reply now, months later.
I am not a tech, so am just restating what the local audio shop told me (and wanted several hundred to replace - I didn't let them go ahead, 'natch).
The display on the unit does not light up when the power button is engaged. I'd be surprised if the power supply circuit board is damaged, as the unit worked fine one day and was DOA the next (no movement of unit, it was in the stereo rack the whole time). I'll check the solder joints for any that look suspect.
How do I go about checking the (7805) regulators ICs to find out if one or more are bad? Is this something I'd be able to do myself, or do I need to take this to a tech?
Thanks for any help you can give!
Thanks stephensank, just saw your reply now, months later.
I am not a tech, so am just restating what the local audio shop told me (and wanted several hundred to replace - I didn't let them go ahead, 'natch).
The display on the unit does not light up when the power button is engaged. I'd be surprised if the power supply circuit board is damaged, as the unit worked fine one day and was DOA the next (no movement of unit, it was in the stereo rack the whole time). I'll check the solder joints for any that look suspect.
How do I go about checking the (7805) regulators ICs to find out if one or more are bad? Is this something I'd be able to do myself, or do I need to take this to a tech?
Thanks for any help you can give!
Very simple. With the negative probe of a voltmeter connected to chassis, and the unit power on, use the positive probe to check voltage on the pin 3(on the right) of the 7805. Should get 5V DC. If you do get that, press down firmly on the board at the 7805 and see if the display comes on. If you do not get 5V, check voltage on pin 1, which should be(no schematic in front of me at the moment) somewhere in the 8-15V vicinity, more or less. Voltage there & not on pin 3 means the 7805 is dead. If you don't have pin 1 voltage, you more than likely have just very cracked solder connections to all three pins.
Hello Forum and Nak owners!
I was wondering if some lucky recipient of the OMS-5 service manual would like to send me/post a copy.
Background:
My friend has just brought me a few non-working CD players. I had told him I wasn't interested until I took a closer look to the OMS-5. Since it looked very well made I told him he could leave it. ;-)
The Issue:
The unit spins the disc, the tray opens and closes on demand but doesn't play the tracks. Could it be a malfunctioning laser unit?
Since everything is tight and "interleaved" I would like to reference a manual in order to get a better idea and before complicating my life even more.
Thanks in advance,
MV
I was wondering if some lucky recipient of the OMS-5 service manual would like to send me/post a copy.
Background:
My friend has just brought me a few non-working CD players. I had told him I wasn't interested until I took a closer look to the OMS-5. Since it looked very well made I told him he could leave it. ;-)
The Issue:
The unit spins the disc, the tray opens and closes on demand but doesn't play the tracks. Could it be a malfunctioning laser unit?
Since everything is tight and "interleaved" I would like to reference a manual in order to get a better idea and before complicating my life even more.
Thanks in advance,
MV