Hi,
i have to replace the spindle motor on my Nakamichi OMS5-EII
(see also http://www.diyaudio.com/forums/showthread.php?s=&threadid=88616&highlight= )
, because the bearings are worn out, the shaft has a little play.
It is a Mabuchi RF 310 TB 11400, the shaft lenght is 16mm.
The only replacement I found was a Mabuchi RF 310 TA 11400 with a shaft lenght of 14 mm. I ll have to replace the brass spacer of 2mm thickness with one of 1mm to regain shaft lenght. Still 1mm in height lost for the clamper, but it should fit.
Of course i can easily fit the disc table in the same height as it was before, no matter what spacer, but maybe the table has lowered in 20 years:
So does anyone know the exact distance from the disc surface to the laser unit, measured from the octangular black housing?
It is a KSS 123A, but as far as I know, the KSS differ mostly more in how they fit into the tracking assembly than in focal lenght.
So, any data?
All the best,
Salar
i have to replace the spindle motor on my Nakamichi OMS5-EII
(see also http://www.diyaudio.com/forums/showthread.php?s=&threadid=88616&highlight= )
, because the bearings are worn out, the shaft has a little play.
It is a Mabuchi RF 310 TB 11400, the shaft lenght is 16mm.
The only replacement I found was a Mabuchi RF 310 TA 11400 with a shaft lenght of 14 mm. I ll have to replace the brass spacer of 2mm thickness with one of 1mm to regain shaft lenght. Still 1mm in height lost for the clamper, but it should fit.
Of course i can easily fit the disc table in the same height as it was before, no matter what spacer, but maybe the table has lowered in 20 years:
So does anyone know the exact distance from the disc surface to the laser unit, measured from the octangular black housing?
It is a KSS 123A, but as far as I know, the KSS differ mostly more in how they fit into the tracking assembly than in focal lenght.
So, any data?
All the best,
Salar
As memory serves, on the OMS-5II/7II, platter height is not covered in the service manual, but in my experience, if the bottom of the outer platter rim is 2-4mm above the laser's black plastic dustcover, it'll work just fine.
Strangely, I've never seen platter motor failure in these machines. Only KSS123 laser failures, and cold solder joints, leaky lytics, etc.
Strangely, I've never seen platter motor failure in these machines. Only KSS123 laser failures, and cold solder joints, leaky lytics, etc.
Hi Stephen!
Platter - you mean the disc table? You are right, the height is not covered in the service manual, but is 2-4mm isn´t too much of tolerance? Does not sound like enough headroom for heavily warped discs.
I simply want to adjust the height more precise when I replace the motor.
The Nak now runs for about 17years almost every day, sometimes for about 3 hrs a day. This is about 18000 hs. of use - I did replace all lytics last fall, as well as the laser.
BTW I measured 4.52 mm between the bottom oft the table and the brass spacer.
I googeled for the distance between CD-surface and laser lens, but found nothing.
Maybe, there are many different focal lenghts.
The KSS-123A laser unit was very common in the mid eighties.
(Denon DCD 1500, also Akai CD73 as far as i remember and of course some Sonys.
Maybe in their service manuals the precise height is mentioned?
All the best, Salar
Platter - you mean the disc table? You are right, the height is not covered in the service manual, but is 2-4mm isn´t too much of tolerance? Does not sound like enough headroom for heavily warped discs.
I simply want to adjust the height more precise when I replace the motor.
The Nak now runs for about 17years almost every day, sometimes for about 3 hrs a day. This is about 18000 hs. of use - I did replace all lytics last fall, as well as the laser.
BTW I measured 4.52 mm between the bottom oft the table and the brass spacer.
I googeled for the distance between CD-surface and laser lens, but found nothing.
Maybe, there are many different focal lenghts.
The KSS-123A laser unit was very common in the mid eighties.
(Denon DCD 1500, also Akai CD73 as far as i remember and of course some Sonys.
Maybe in their service manuals the precise height is mentioned?
All the best, Salar
I have a service manual for a OMS-4 and the precise height is mentioned. E-mail Anatech,he at one time was a authorized Nakamichi serviceman .He should be able to shed some light on the subject.😉
Salar said:
With the laser's dustcover, which is roughly the same plane as the center of the lens vertical travel, 2-4mm below the bottom of the platter rim, you have that 2-4mm PLUS the thickness of the platter at that point, which is another 1-2mm. So, plenty of clearance, unless your cd's have been left on the dashboard of a closed car on a Tucson summer day. If it doesn't work perfectly at that adjustment range, their is something else wrong.
Hi Xeaglekeeper!
was the same laser (KSS-123A) used in the OMS-4? (They did not mention the type in the service manual of the OMS-5II/7II)
What is the exact height, could you give me the data from the service manual or send a scan?
salar at snafu dot de , thanx
Stephensank, I measured 2mm from the top of the rim to the dustcover (without the rubber damper, which was glued on the dustcover by Nakamichi.) The thickness of the rim is already 1.25mm. As far as I remember, the magnetic holder would not allow a height of 4mm plus rim.
I know anatech, he was very kind in helping me with laser alignment of the OMS-5/7II.
I will email him.
For those who still might have the OMS-5 II / OMS-7 II, and search for replacements, here are the parts:
Laser:
Sony KSS-123A (hard to get, got mine from AKAI)
Spindle motor:
Mabuchi RF 310-TB-11400, shaft lenght 16mm / diameter 2mm
(not available any more, RF 310-TA-11400 might work, available in 14/22mm shaft lenghts)
Laser feed motor:
Copal Mini Motor 87 (no info on this, all successors have completely different numbers)
Tray motor:
Copal Mini Motor 8A (no info on this, all successors have completely different numbers)
All the best,
Salar
was the same laser (KSS-123A) used in the OMS-4? (They did not mention the type in the service manual of the OMS-5II/7II)
What is the exact height, could you give me the data from the service manual or send a scan?
salar at snafu dot de , thanx
Stephensank, I measured 2mm from the top of the rim to the dustcover (without the rubber damper, which was glued on the dustcover by Nakamichi.) The thickness of the rim is already 1.25mm. As far as I remember, the magnetic holder would not allow a height of 4mm plus rim.
I know anatech, he was very kind in helping me with laser alignment of the OMS-5/7II.
I will email him.
For those who still might have the OMS-5 II / OMS-7 II, and search for replacements, here are the parts:
Laser:
Sony KSS-123A (hard to get, got mine from AKAI)
Spindle motor:
Mabuchi RF 310-TB-11400, shaft lenght 16mm / diameter 2mm
(not available any more, RF 310-TA-11400 might work, available in 14/22mm shaft lenghts)
Laser feed motor:
Copal Mini Motor 87 (no info on this, all successors have completely different numbers)
Tray motor:
Copal Mini Motor 8A (no info on this, all successors have completely different numbers)
All the best,
Salar
Salar
No problem......You will have to enable e-mail in your control panel or provide a e-mail address 🙂
Dave
No problem......You will have to enable e-mail in your control panel or provide a e-mail address 🙂
Dave
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