Hello Salar,
nice to see some message from you. Hope all is fine. Pity that there is no time to continue the work on this topic 😎
Hi community,
I've read carefully the many posts above but since none mentioned it, I'm confused on the recalibration process needed after having replaced the diode. Do
Assuming the photodiode is aligned with the procedure described by @ManoloMos, when the adjustment of the three screws in the picture takes place in your practice?
Does it take place with the pickup remounted on the player or when it's still mounted on the alignment rig?
How do you set the tangential and radial screws (red)?
What's the purpose of the hexagonal screw (green)?
Unfortunately during the LD replacement I had to unscrew these three screws to remove the focusing assembly which is sits above the screw blocking the main optical group.
Finally, with regard to E-FBalance /F. Bias Adjustment do you go through the procedure described in the Service Manual (see below)? And you do this after or before screws adjustment?
Thanks again for your time and suggestions and congratulations to anyone having already succeeded in the LD swap!
Last but not least, the most sincere gratitude for @ManoloMos goodness on sharing his initial findings.
Riccardo
I've read carefully the many posts above but since none mentioned it, I'm confused on the recalibration process needed after having replaced the diode. Do
Assuming the photodiode is aligned with the procedure described by @ManoloMos, when the adjustment of the three screws in the picture takes place in your practice?
Does it take place with the pickup remounted on the player or when it's still mounted on the alignment rig?
How do you set the tangential and radial screws (red)?
What's the purpose of the hexagonal screw (green)?
Unfortunately during the LD replacement I had to unscrew these three screws to remove the focusing assembly which is sits above the screw blocking the main optical group.
Finally, with regard to E-FBalance /F. Bias Adjustment do you go through the procedure described in the Service Manual (see below)? And you do this after or before screws adjustment?
Thanks again for your time and suggestions and congratulations to anyone having already succeeded in the LD swap!
Last but not least, the most sincere gratitude for @ManoloMos goodness on sharing his initial findings.
Riccardo
Attachments
One more (silly) question: for the hexagonal fixing element (see green arrow above) the mounting sequence is spring - washer - nut or washer- spring + nut?
I honestly don’t remember nor I noted down when I dismantled it 😱
Thank you again
I honestly don’t remember nor I noted down when I dismantled it 😱
Thank you again
Last edited:
To simplify the question above, I've represented the three potential options on installing the spring.
Its adjustment is realized is with the laser pickup mounted, with a CD running and looking the best RF signal shape. This adjustment is called in other CDs pickups tangential or azimuth adjust.
When you perform the laser replace and optodiode place adjust, the perfect 90º azimuth is not reached, so, once you install the laser pickup, with the torx screws, you adjust the azimuth to the theoretical 90º alignment.
Hexagonal screw with the spring is used to apply a constant force but allowing mobility to the torx screws adjust.
And don't forget, that the lens can be moved front to rear and left to righgt, you have to find the best position. I know, it is not easy. The position is not critic, but must be performed a adjust to reach the max signal.
When you perform the laser replace and optodiode place adjust, the perfect 90º azimuth is not reached, so, once you install the laser pickup, with the torx screws, you adjust the azimuth to the theoretical 90º alignment.
Hexagonal screw with the spring is used to apply a constant force but allowing mobility to the torx screws adjust.
And don't forget, that the lens can be moved front to rear and left to righgt, you have to find the best position. I know, it is not easy. The position is not critic, but must be performed a adjust to reach the max signal.
"Unfortunately during the LD replacement I had to unscrew these three screws to remove the focusing assembly which is sits above the screw blocking the main optical group."
Yes, you must dismantle the focusing assemble, it is necessary for to remove the optic block for to remove the laser diode.
Torx screws usually are screwed a bit, no much force. For this reason, in factory the focusin assemble is sealed with glue.
Yes, you must dismantle the focusing assemble, it is necessary for to remove the optic block for to remove the laser diode.
Torx screws usually are screwed a bit, no much force. For this reason, in factory the focusin assemble is sealed with glue.
About E-F adjust, I remember that service manual adjust procedure did not help me very much. I remember that I connected TES to ground and nothing happened, so this adjust was performed by essay error method, using a good cd and a scratched or bad cd, the adjust is perfomed in that way that can read both CDs.
Thanks a lot Manolo for all your comments.
I’m pretty familiar with such alignment on Pioneer pickups but on Sony they are far from being practical and are not designed for maintenance.
Thanks again for your time and expertise
I’m pretty familiar with such alignment on Pioneer pickups but on Sony they are far from being practical and are not designed for maintenance.
When you initially re-mount the pickup after LD swap and photodiode adjustment, do you already get a “decent” RF signal that you improve by adjusting the two screws or do you actually get a non-sense signal that only after many trials and errors results in a usable eye pattern ?
What do you recommend executing first: focus assembly alignment or EF calibration?
Thanks again for your time and expertise
Do you mean these directions? I've very little clearance on these directions, almost zero
Yes, exactly. The draw describes perfectly what I meant to saly. Another tip: Sometimes this adjustment is not much, and sometimes is very critical. And I remember a KSS-151a I bought as faulty in Ebay, the lens block was good at first glance, but its performance was horrible. I changed the moving lens for another, and worked well.
So, the lens can be fault too. Why the lens was bad? I don't know, maybe its suspension, maybe the plastic lens was defect. The important is that you must know that moving lens can be faulty, and can be replaced for another one, from scrap or chinese KSS-213a or similar. It works. In anoher thread, I tell that I used a lens from a chinese KSS for a Pioneer laser pickup which lost its lens, and it worked perfectly. Pioneer lens uses a glue that degradates and the lens falls. A typical fault.
Yes, azimuth or angle adjust can be performed in Pioneer or other brands, but in this KSS the screws are sealed, it is not impossible, but is not designed for to manipulate. But in this case, adjust is necesary.
First focus, and then EF.
Few weeks ago I found in Ebay a KSS-151a for 23€, shipping costs apart in Bosnia. It arrived with the two coils for the movement. One of this, the one with the wire more thin was broken, maybe it belonged to an Akai, I've seen in this forum this coil in Akai cd players are prone to failure.
Well, I install it in my scrapped Denon DCD1500II and the cd was not loaded. It develop 130uW. I increase it until 200uW and now it works. I tried to adjust the tiny torx that are below for azimuth adjust, but it was good from factory. Some adjust here and there and 1Vpp and clean signal. In the label is writed 48mA. Now is 55mA.
So, increasing a little bit laser power, the laser pickup is funtional and running correctly.
Does it worth to replace laser diode? No. The signal is correct, clean, and the laser diode is working well.
Why the laser pickup left to worlk?
Photodiode lost efficiency. I don't think.
Dirt. I don't think. When the optic is dirt, the RF signal is noisy.
Laser? I don't have instruments for to analyze a worn laser diode. As is known, a laser signal is a light very pure in frecuency and PHASE. Phase is very important in CD laser pickup. If for any reason, phase purity is lost, the laser pickup performance is worst.
What to do? Firstly, try to increase power. If it works, RF signal is clear, laser diode current is normal, and the general performance is good, DON'T TOUCH IT MORE.
In this forum someone said that Sanyo technical documents about laser pickup said that before replace laser pickup, it should try to increase laser power.
Don't forget that a laser power meter is very useful. Without it is almost impossible to do this kind of experiments.
Well, I install it in my scrapped Denon DCD1500II and the cd was not loaded. It develop 130uW. I increase it until 200uW and now it works. I tried to adjust the tiny torx that are below for azimuth adjust, but it was good from factory. Some adjust here and there and 1Vpp and clean signal. In the label is writed 48mA. Now is 55mA.
So, increasing a little bit laser power, the laser pickup is funtional and running correctly.
Does it worth to replace laser diode? No. The signal is correct, clean, and the laser diode is working well.
Why the laser pickup left to worlk?
Photodiode lost efficiency. I don't think.
Dirt. I don't think. When the optic is dirt, the RF signal is noisy.
Laser? I don't have instruments for to analyze a worn laser diode. As is known, a laser signal is a light very pure in frecuency and PHASE. Phase is very important in CD laser pickup. If for any reason, phase purity is lost, the laser pickup performance is worst.
What to do? Firstly, try to increase power. If it works, RF signal is clear, laser diode current is normal, and the general performance is good, DON'T TOUCH IT MORE.
In this forum someone said that Sanyo technical documents about laser pickup said that before replace laser pickup, it should try to increase laser power.
Don't forget that a laser power meter is very useful. Without it is almost impossible to do this kind of experiments.
Hi @ManoloMos and thanks again for the great work. What Rohm part number have you used as the correct diode for KSS-151a?
In the US I use digikey or mouser to obtain parts, and I see they do have a selection of Rohm diodes available. Please advise which ones will work. Thank you!!!
In the US I use digikey or mouser to obtain parts, and I see they do have a selection of Rohm diodes available. Please advise which ones will work. Thank you!!!
Ok one more:
https://www.us-lasers.com/n780nm5m.htm
I believe the key specs are:
5.6mm pkg
780nm
35ma (max 50ma)
5mw
But perhaps other things are important, such as beam divergence or astig etc.? Please advise, thanks!
https://www.us-lasers.com/n780nm5m.htm
I believe the key specs are:
5.6mm pkg
780nm
35ma (max 50ma)
5mw
But perhaps other things are important, such as beam divergence or astig etc.? Please advise, thanks!