so you are working on a fixture to be able to replace the diod with other one and be able to calibrate it correct?
Hi John,
There is a critical adjustment in all multi-beam laser heads. This is the proper adjustment of the diffraction grating, and it is a very sensitive alignment. If you don't have the tool that fits exactly, you simply will not be able to adjust it correctly. On these heads, the resistance of the movement is also critical (= pain in the rear) so that you can move it, but it won't slide or shift by itself. Salar can tell you how pointless it is to try.
At some point, the output has to be measured (so many mW) and at such and such a current level. We need to figure out what that optical power level is so that we can set the heads to the proper level and list the current draw new on the head. You are allowed a 10% increase before calling the head unfit for service. What is really nice is that laser diodes are more efficient today, and that greatly increases their life as the required current level is lowered.
One thing to be very, very careful of is the laser power level. As you increase the current, the optical power is increased. However, there will be a point where suddenly the optical power drops to zero. Once you have hit that point, and you have no warning, the laser is done and will never emit a laser beam ever again. Garbage.
For this effort, the diode has an orientation with only a little wiggle room. Once the diode is mounted, the only other adjustments are the diffraction grating and the laser power level. So, if the diffraction can't be adjusted, you are dead in the water.
-Chris
There is a critical adjustment in all multi-beam laser heads. This is the proper adjustment of the diffraction grating, and it is a very sensitive alignment. If you don't have the tool that fits exactly, you simply will not be able to adjust it correctly. On these heads, the resistance of the movement is also critical (= pain in the rear) so that you can move it, but it won't slide or shift by itself. Salar can tell you how pointless it is to try.
At some point, the output has to be measured (so many mW) and at such and such a current level. We need to figure out what that optical power level is so that we can set the heads to the proper level and list the current draw new on the head. You are allowed a 10% increase before calling the head unfit for service. What is really nice is that laser diodes are more efficient today, and that greatly increases their life as the required current level is lowered.
One thing to be very, very careful of is the laser power level. As you increase the current, the optical power is increased. However, there will be a point where suddenly the optical power drops to zero. Once you have hit that point, and you have no warning, the laser is done and will never emit a laser beam ever again. Garbage.
For this effort, the diode has an orientation with only a little wiggle room. Once the diode is mounted, the only other adjustments are the diffraction grating and the laser power level. So, if the diffraction can't be adjusted, you are dead in the water.
-Chris
... and after Chris has managed to fit in the diode, another obstacle will occur:
As all original Diodes available are ESD-garbage. I did buy 50 Sharp LT022MC diodes
these were the diodes in EVERY first and second generation CD-Player, no matter european or asian.
10 did meet the optical output power, I send those to Chris with a BU-1 Transport to work on (Which I misaligned by mistake).
I also donated a working Player with BU-1C to have a reference.
But bottom line, after Chris figured the workflow with the
original diodes, we will be forced to use diodes from today because there is no reliable, original stock
Today´s diodes have a smaller can, this can be adressed by milling an adaptor, more or less a small brass ring.
But today´s "de facto" standard how the Monitor Diode is connected to the Laser Diode is different today from what was more common back then.
I always mix up whether it is common anode or cathode, but it does not fit.
So this has to be adressed as well at a later point... So you see, many problems to solve in 2020 - Happy new year to all!
As all original Diodes available are ESD-garbage. I did buy 50 Sharp LT022MC diodes
these were the diodes in EVERY first and second generation CD-Player, no matter european or asian.
10 did meet the optical output power, I send those to Chris with a BU-1 Transport to work on (Which I misaligned by mistake).
I also donated a working Player with BU-1C to have a reference.
But bottom line, after Chris figured the workflow with the
original diodes, we will be forced to use diodes from today because there is no reliable, original stock
Today´s diodes have a smaller can, this can be adressed by milling an adaptor, more or less a small brass ring.
But today´s "de facto" standard how the Monitor Diode is connected to the Laser Diode is different today from what was more common back then.
I always mix up whether it is common anode or cathode, but it does not fit.
So this has to be adressed as well at a later point... So you see, many problems to solve in 2020 - Happy new year to all!
Last edited:
check out post #31 under
https://www.diyaudio.com/forums/dig...-diode-applicable-kss-151a-4.html#post6733000
https://www.diyaudio.com/forums/dig...-diode-applicable-kss-151a-4.html#post6733000
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and an offer for a pdf instruction manual for diy:
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or
https://www.ebay.com.my/itm/204060407032