Thanks to you all for your help. I shall give these suggestions a go and see if I get anywhere. To access the test points on the RF board the machine has got to either lie on its side or upside down so hopefully these tests are not carried out with a cd spinning, unless as mentioned above a cd has to be spinning to read an rf pattern.
Hi! A very necessary data is the laser diode current. You can determine the health of the laser diode with this data.
For this, you must measure in R003. In the manual service the resistance value is not shown.
Other thing you can is if the lens that is below the focus lens is clean or have any problem. This lens is formed with two lens glued. In some cases, the glue is corromped, and it turns turb.
Some pics of a degradated BU-1E lens:
BU-1C Disease - Google Photos
For this, you must measure in R003. In the manual service the resistance value is not shown.
Other thing you can is if the lens that is below the focus lens is clean or have any problem. This lens is formed with two lens glued. In some cases, the glue is corromped, and it turns turb.
Some pics of a degradated BU-1E lens:
BU-1C Disease - Google Photos
Hi! I moved the lens a bit, just necessary for to see the lens with a lens... it sounds a bit redundant!
To clean the lens don't work, because thse lens is formed with two two lens sticked with transparent glue. This transparent glue is the problem, sometimes it gets corrupt, and you can see like a cloud, a fog...
To clean the lens don't work, because thse lens is formed with two two lens sticked with transparent glue. This transparent glue is the problem, sometimes it gets corrupt, and you can see like a cloud, a fog...
As you can see in the pictures, for to remove the lens, I broke the lens in a corner.
The most practical solution is another lens. This part used in BU-1 is similar that used in KSS-121A, and I think KSS-120, 122A and KSS-123A. I have the BU-1E with the bad lens keeped in shelf, I hope to repair it someday.
A bit off topic for Salar. I've adjusted the grating in the Pioneer P-DX700 and P-D70. It was necessary because I dismantled the unit for to clean it. But if you don't touch, you don't have to adjust it. When it is bad ajusted, the Tracking Balance is not well performed, some discs are not well played.
The most practical solution is another lens. This part used in BU-1 is similar that used in KSS-121A, and I think KSS-120, 122A and KSS-123A. I have the BU-1E with the bad lens keeped in shelf, I hope to repair it someday.
A bit off topic for Salar. I've adjusted the grating in the Pioneer P-DX700 and P-D70. It was necessary because I dismantled the unit for to clean it. But if you don't touch, you don't have to adjust it. When it is bad ajusted, the Tracking Balance is not well performed, some discs are not well played.
Thanks for the answer, but are the lenses made from glass?
About the grating: Theoretically what would
the angle of the grating be in correspondence
to the track of a CD? About 90 degrees?
Second: Did you align the grating directly in the Pioneer PD70?
(I do not have one)
Because in the Service manual it is not clear, what optical part is moved
though they call it grating adjustment.
If the hole for adjusting is horizontally under the lens,
it is the grating. If it is not, it might be the tube lens
that focuses the beams to the photodiodes A to F.
Or is the grating not adjusted directly but corrected /adjusted
by the tube lens, that focuses the beam on the photodiodes?
This is something I would like to understand.
I might be wrong but If I remember physics
from school correctly, the grating does not
influence the angle of the side beams, but the brightness.
So the grating decides how much light is emitted on the E-F diodes...?
Best, Salar
About the grating: Theoretically what would
the angle of the grating be in correspondence
to the track of a CD? About 90 degrees?
Second: Did you align the grating directly in the Pioneer PD70?
(I do not have one)
Because in the Service manual it is not clear, what optical part is moved
though they call it grating adjustment.
If the hole for adjusting is horizontally under the lens,
it is the grating. If it is not, it might be the tube lens
that focuses the beams to the photodiodes A to F.
Or is the grating not adjusted directly but corrected /adjusted
by the tube lens, that focuses the beam on the photodiodes?
This is something I would like to understand.
I might be wrong but If I remember physics
from school correctly, the grating does not
influence the angle of the side beams, but the brightness.
So the grating decides how much light is emitted on the E-F diodes...?
Best, Salar
Last edited:
In this japanese blog is talked about a BU-1E laser pickup. It tells in a comment about the cited problem of the fog in the lens: "Cloudy plastic lens I think this is the main cause
Deterioration of silicone rubber
Laser output reduction"
Responding to Salar, I've read that, depending if it is BU-1, BU-1C or BU-1E, the focus lens can be made of cristal or plastic. But this lens is not the problem. I suppose the other lens are made of cristal.
"So the grating decides how much light is emitted on the E-F diodes...?" The anwer is firm: Yes.
In spite the confuss of the adjust in the Pioneer P-D70 grating adjust, the important, what it underlie, is to get the most amount of Tracking Balance signal, that is what you said, the most signal in E-F diodes.
The adjust was hard, because the entire mechanism must to be removed out the chasis, and I had tu build another excentric screw, but it worked.
I had to adjust the grating because the pickup was dismantled for to clean up it. However, the most practical is not touch this adjust.
If this adjust is not well performed, some disc are not well played, or problems at the begining or at the end of the discs.
So, in BU-1 pickups, do not touch the grating lens if it is not necesary.
Deterioration of silicone rubber
Laser output reduction"
Responding to Salar, I've read that, depending if it is BU-1, BU-1C or BU-1E, the focus lens can be made of cristal or plastic. But this lens is not the problem. I suppose the other lens are made of cristal.
"So the grating decides how much light is emitted on the E-F diodes...?" The anwer is firm: Yes.
In spite the confuss of the adjust in the Pioneer P-D70 grating adjust, the important, what it underlie, is to get the most amount of Tracking Balance signal, that is what you said, the most signal in E-F diodes.
The adjust was hard, because the entire mechanism must to be removed out the chasis, and I had tu build another excentric screw, but it worked.
I had to adjust the grating because the pickup was dismantled for to clean up it. However, the most practical is not touch this adjust.
If this adjust is not well performed, some disc are not well played, or problems at the begining or at the end of the discs.
So, in BU-1 pickups, do not touch the grating lens if it is not necesary.
I think I remember this thread, it could be chinese.
Looking at the disassembled tube with the diode in the bottom
and the collimation lens that fogs on the top:
There is a slot, could it be for the grating?
And could the sweet spot for aligning the grating
simply be to measure the light output as a whole,
main beam and side beams and just find the spot
where most of light is emitted?
This measurement should be simple.
Or is the lightness of the main beam also affected by the grating?
Best Salar
Looking at the disassembled tube with the diode in the bottom
and the collimation lens that fogs on the top:
There is a slot, could it be for the grating?
And could the sweet spot for aligning the grating
simply be to measure the light output as a whole,
main beam and side beams and just find the spot
where most of light is emitted?
This measurement should be simple.
Or is the lightness of the main beam also affected by the grating?
Best Salar
Last edited:
I searched the web for one hour now but did not find the blog.
PITA as google tweaks the search to sell you crap.
But at least translation has become better, there is a chinese thread
about the BU-1C:
Google Translate
General Question:
The fog is only visible when the tube is disassembled?
Best, Salar
PITA as google tweaks the search to sell you crap.
But at least translation has become better, there is a chinese thread
about the BU-1C:
Google Translate
General Question:
The fog is only visible when the tube is disassembled?
Best, Salar
Last edited:
Remove or move the focus lens? This means raising a bit?
Also how does foggyness impact the eyepattern?
Blurry or noisy eyepattern?
Or no signal at all and no reading of TOC?
I made this mod
https://www.diyaudio.com/forums/dig...er-life-amplifying-current-7.html#post5604526
on several BU-1C today.
All eyepatterns are more or less the same,
so I assume they are not foggy...
Also how does foggyness impact the eyepattern?
Blurry or noisy eyepattern?
Or no signal at all and no reading of TOC?
I made this mod
https://www.diyaudio.com/forums/dig...er-life-amplifying-current-7.html#post5604526
on several BU-1C today.
All eyepatterns are more or less the same,
so I assume they are not foggy...
Remove or move? I don't remember. You do what is necesary, with care, to see the lens.
The lens foggy afects in attenuation of the laser signal, and difraction. In the BU-1 that I showed, the RF signal was right, but the laser power power at the lens was more than 700uW, almost three times the normal power.
The lens foggy afects in attenuation of the laser signal, and difraction. In the BU-1 that I showed, the RF signal was right, but the laser power power at the lens was more than 700uW, almost three times the normal power.
Good to hear, I only checked the eyepatterns that were
about 0.8V p-p before the mod, 1.2 after, then laser power was
lowered to 1Vpp as stated in the manual.
I am sure this was described somewhere,
I assume I measure power across the green resistor on
the flexible board that holds the diode?
about 0.8V p-p before the mod, 1.2 after, then laser power was
lowered to 1Vpp as stated in the manual.
I am sure this was described somewhere,
I assume I measure power across the green resistor on
the flexible board that holds the diode?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.