KSS-122A and KSS-123A - Are they Interchabgeable?

[Salar]

As i posted in another thread, I try to improve the tracking abilities of my Nak CD-Player, which uses a KSS-123A Laser. Regardless if the laser is old or new (got 2 spares) and how much time is spent bringing the servo setup into ballpark, tracking abilities are mediocre.
Then I started research on other players, using the same CX20109 / CX 20108 chipset for RF-Amp and servo control.
Found a CDP-40 from 1986, got it for 1,50$ from ebay. I was surpised: Even though the CDP-40 was dirty and never serviced in 23 years, the eyepattern is cleaner and less jittery than the Nak´s eyepattern. Also E-F balance is cleaner. Tracking is better, over a variaty of discs.

The servo amplification of the CDP-40 is different than the Naks, so I hope, this is the cause for better tracking.

The laser is a Sony KSS-122A, the "Player vs Transport List" fluctuating in the web states it should be a KSS-123A, the service manual states a KSS-120C.

So, before I waste a day fiddling the Naks KSS-123A transport to the CDP-40s servo control:

Does anyone know, wether the KSS-122A and KSS-123A were interchangeable?
All the best,
Salar

[Mooly]

The Sony D50 Discman (mk1) used that chipset.
Is the eye patern "jittery" as you call it because of pickup in the leads to it. This was a common effect on many players. If you bring your hand near the leads to it, does it go worse ?
Also make absolutely certain you use the correct ground point for measureing as the use of an incorrect one can "add" noise to the reading that isn't really there.

[Salar]

Hello Mooly,
we discussed this earlier, I did use the correct ground point. But I also have to say, the CDP-40 Service manual gives instructions on that, on the Nak, I used the a ground connection as close as possible to the RF.
Especially the upper and lower edges of the eyepattern are cleaner in the CDP-40, you can see the small diamond shapes more clearly.
I replaced the KSS-122A Laser with the KSS-123A in the CDP-40 to check interchangeability.
Form-factor and on-board circuit connections are identical, the lens also travels up and down, but no light is emitted. (A simple way is using a video camera for monitoring) I might have blown the diode by electrostatic electricity, but i do not think so, I did solder / unsolder the short circuit only when evrything was connected....
All the best, Salar

[Mooly]

Don't know if they are fully interchangeable or not. Perhaps put the shorting links back and trace out the Laser Diode connections to be sure.
You haven't any leakage from your soldering iron that could zap anything have you ?
I have seen that happen in the past. Maybe unplug it at the vital moment or use a gas iron.

[Salar]

Hello Mooly,
laser connections are the same. Traces on both units are identical.
I can not swear that the iron did not zap the diodes, but the whole circuitry was reassembled before unsoldering the short-circuit joints. if a simple iron solder (not grounded) can zap the diode in this state, any touch during servicing could do as well...

Do you remember the CDP-203ES? Another candidate of servo circuitry design for the KSS-123A, but I guess, this one had a linear motor and brushless spindle motor?

If you recall any good player using the KSS-123A / CX20109 / CX2018 / CX23035 chipset, any hints would be appeciated...
All the best,
Salar

[Mooly]

If the iron is ungrounded suppose it could have leakage.
I would work with CD unplugged and for actually unsoldering the shorting link, unplug the iron too... and just touch something at ground and the CDP and the iron before you make contact. The theory says it takes only a spike lasting pico seconds to damage a laser. If the connections are identical and one lights and the other doesn't then it sounds like it's zapped. Is the pot on the pickup the same value between the two (the printed value)... or was the actual laser diode type different between the two requiring different feedback from the photodiode on the laser chip itself. Very unlikely.

I used to have Denon DCD1500 mk 1 can't remember what that used though.

[tiefbassuebertr]

Originally Posted by Salar

Hello Mooly,
we discussed this earlier, I did use the correct ground point. But I also have to say, the CDP-40 Service manual gives instructions on that, on the Nak, I used the a ground connection as close as possible to the RF.
Especially the upper and lower edges of the eyepattern are cleaner in the CDP-40, you can see the small diamond shapes more clearly.
I replaced the KSS-122A Laser with the KSS-123A in the CDP-40 to check interchangeability.
Form-factor and on-board circuit connections are identical, the lens also travels up and down, but no light is emitted. (A simple way is using a video camera for monitoring) I might have blown the diode by electrostatic electricity, but i do not think so, I did solder / unsolder the short circuit only when evrything was connected....
All the best, Salar

I guess, either the monitor diode or the laser diode itself uses reverse polarity.
The only player kss122A inside is the CDP-70 from Sony
Kss-123A inside by follow (not all yourself checked !!!)

AKAI CD93
NEC CD610, CD810
Braun CD3 CD4 KSS 123A = Sony ordercode 884805601, Braun order code 198650199)
Onkyo: DX200 DX2200 3200 6450 according ebay auction: DX220-320-645
Dual CD-41 1030 -1025 - 150 - 20 CDP4500
MULTITECH CD61O KSS123A
Nordmende CP 3000
NAKAMICHI OMS-3E, OMS-4E, OMS-5E II, OMS-7E II, OMS-30
Denon DCD 1000 1100 1300 1500 1700 300 3300 500 700 900
Sony CD 1200 CDP 203 CDP-203ES 30 33 40 45 50 55 65 70 7F
HARMAN KARDON HD500
SABA CD1015, CD1O15V1 KSS123A
SABA CD1O16V1 KSS123A
SABA CD2O15RC KSS123A
SABA DAD800TV1 KSS123A
SANSUI CDE7O KSS123A
SANSUI CDE750 KSS123A
SANSUI CDV35O KSS123A
SANSUI CDV55O KSS123A
SCHNEIDER CDA30 KSS123A
SCHNEIDER CDP7400 KSS123A
SCHNEIDER CDP7600 KSS123A
TELEFUNKEN HS975V1 KSS123A
TELEFUNKEN HS81OV1 KSS123A
TELEFUNKEN CD300V1 KSS123A
TOSHIBA XR3O KSS123A
TOSHIBA XR35 KSS123A
TOSHIBA XRV12/15 KSS123A

If you order service manual of CDP-70 and one of the other for compare, you will find the reason

[Salar]

Hm, not to mention all the Sony´s with KSS-123A.
Checked your homapage, tiefbassübertragug, very good and informative.
Ok to make things more complicated:
My CDP-40 has a KSS-122A, looks alike a twin to the KSS-123.

But the Service Manual says it is be a KSS-120C.

I attached the schematics of CDP-40 and Nak. looks like the the diodes have reverse polarity, or am I wrong? Hope I am right, or else I might have zapped a laser, which is worth 180$ nowadays.
All the best, Salar

[Mooly]

It does appear to be different (and correct in the diagram) as the NAK drives the LD from Ground (anode +) to minus 5 volts (cathode -)

[Salar]

Hello Mooly,
the Nak is KSS-123A. So, to make the KSS-123A work inthe Sony´s CDP-40 servo circuitry, I simply swap the connections to the Laser diode?.
All the best, Salar