Disc Table Height with KSS-Laser Units - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th February 2007, 12:07 PM   #1
Salar is offline Salar  Germany
diyAudio Member
 
Join Date: Feb 2006
Location: Germany
Default Disc Table Height with KSS-Laser Units

Hi,
i have to replace the spindle motor on my Nakamichi OMS5-EII
(see also How to get your beloved CD-player from the eighties into the Digital Domain )
, 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
  Reply With Quote
Old 24th February 2007, 09:53 PM   #2
diyAudio Member
 
Join Date: Oct 2006
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.
  Reply With Quote
Old 24th February 2007, 10:42 PM   #3
Salar is offline Salar  Germany
diyAudio Member
 
Join Date: Feb 2006
Location: Germany
Hi Stephen!
Platter - you mean the disc table? You are right, the height is not covered in the service manual, but is 2-4mm isnīt 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
  Reply With Quote
Old 25th February 2007, 01:15 AM   #4
diyAudio Member
 
XEAGLEKEEPER's Avatar
 
Join Date: Jan 2006
Location: central Iowa
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.
__________________
Ret. USAF... AKA- Avionic *** Solder slinger for hire...***
  Reply With Quote
Old 25th February 2007, 06:14 AM   #5
diyAudio Member
 
Join Date: Oct 2006
Quote:
Originally posted by Salar
Hi Stephen!
Platter - you mean the disc table? You are right, the height is not covered in the service manual, but is 2-4mm isnīt 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

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.
  Reply With Quote
Old 25th February 2007, 10:15 AM   #6
Salar is offline Salar  Germany
diyAudio Member
 
Join Date: Feb 2006
Location: Germany
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
  Reply With Quote
Old 25th February 2007, 11:51 AM   #7
diyAudio Member
 
XEAGLEKEEPER's Avatar
 
Join Date: Jan 2006
Location: central Iowa
Salar
No problem......You will have to enable e-mail in your control panel or provide a e-mail address

Dave
__________________
Ret. USAF... AKA- Avionic *** Solder slinger for hire...***
  Reply With Quote
Old 25th February 2007, 12:58 PM   #8
diyAudio Member
 
Sonusthree's Avatar
 
Join Date: Dec 2005
Location: Sussex, UK
Quote:
Originally posted by Salar
..........salar at snafu dot de , thanx ...........
All the best,
Salar
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need cross reference for Theta Data basic II Laser disc\cd player gto127 Digital Source 16 21st October 2010 03:32 AM
Converting CAL CL10 5 disc player to a single disc player stoolpigeon Digital Source 0 27th May 2007 02:25 PM
laser disc players as cd transport? miles488 Everything Else 10 24th June 2006 08:25 AM
Identifying optical pickups/ laser units kora Digital Source 7 24th June 2005 12:11 PM
14 Units NOS Philips CDM9/44 Laser Mechanism tone Swap Meet 2 18th October 2004 05:00 AM


New To Site? Need Help?

All times are GMT. The time now is 10:15 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2