Hi Karl
You do need test discs to set the laser power and focus gains. Running the laser power up to maximum should have burned out the laser diode, so as soon as you try the extremes of laser current adjustment, consider the laser scrap. If you don't have the equipment, including the laser power meter (Leader LPM-8000 or 8001), this is an area where you shouldn't tread.
-Chris
You do need test discs to set the laser power and focus gains. Running the laser power up to maximum should have burned out the laser diode, so as soon as you try the extremes of laser current adjustment, consider the laser scrap. If you don't have the equipment, including the laser power meter (Leader LPM-8000 or 8001), this is an area where you shouldn't tread.
-Chris
YEDS 18 Image
I was looking around for the Sony alignment and test disc for it. I think it was
type 4 YEDS 18. Imagine that! caps being the usual suspects.
I didn't see any obvious signs hoping to avoid tearing into it.
I should have known. I don't know enough to like it or not
then found out it didn't have the s1 chip.
Cheers,
I was looking around for the Sony alignment and test disc for it. I think it was
type 4 YEDS 18. Imagine that! caps being the usual suspects.
I didn't see any obvious signs hoping to avoid tearing into it.
I should have known. I don't know enough to like it or not
then found out it didn't have the s1 chip.
Cheers,
Hi Chris,
I guess we all have our own methods for setting such things as focus/tracking gain.
I know you know, you know I know 🙂
Laser power is a different kettle of fish. A power meter is the only way to set the optical output from a pickup although its no guarantee (depending of the condition of the pickup) that you are not overdriving the laser electrically. You need to make a judgement based on observed RF levels, optical output and also current draw of the diode.
Like looking at a bulb behind several layers of glass and optics, if somethings amiss or dirty then the only way to get the desired optical output is to turn the drive up. The pickup then meets its spec for optical output but you could be overdriving the laser to get it.
I would say that looking at RF levels on a scope is probably the safest way to make a quick judgement for an average user.
I guess we all have our own methods for setting such things as focus/tracking gain.
I know you know, you know I know 🙂
Laser power is a different kettle of fish. A power meter is the only way to set the optical output from a pickup although its no guarantee (depending of the condition of the pickup) that you are not overdriving the laser electrically. You need to make a judgement based on observed RF levels, optical output and also current draw of the diode.
Like looking at a bulb behind several layers of glass and optics, if somethings amiss or dirty then the only way to get the desired optical output is to turn the drive up. The pickup then meets its spec for optical output but you could be overdriving the laser to get it.
I would say that looking at RF levels on a scope is probably the safest way to make a quick judgement for an average user.
Hi Karl,
Yes, agree.
Looking at the eye pattern tells an expert a lot about the unit he is looking at.
-Chris
Yes, agree.
Looking at the eye pattern tells an expert a lot about the unit he is looking at.
-Chris
Same issue with an RCD-855
I have the same issue (disc rotating wrong way around), even after swapping the CDM 4/19 pickup as I suspected by earlier tips I got from German forums that it is most likely the culprit.
I verified that the "new" pickup worked by testing if the player (cheaper Philips one) worked, which it did. I wanted to test the unit from the Rotel inside the Philips, but I couldn't get it to work, but now I think that I connected something wrong since the plugs and sockets for the motors (spindle, tray) were different in between the two players. I've thrown the Philips player and the original unit from the Rotel out, since I moved a few months ago and since I though that original pickup was toast, anyways.
Now, as I again tried to get the Rotel back up with the "new" pickup (beforehand I also tried it but couldn't get anything to work, I didn't find the photos I took when first opening it so I assumed that I connected the wires wrongfully since there was one more socket on the PCB than necessary, between each attempt there were a few months were I didn't work on that issue at all) I connected everything correctly as documented by those photos, and, as mentioned before, the original issue persists.
And, I have a new issue. It wouldn't close the tray when I press the button, opening is fine, but way noisier than I remember. When it is open and I press the button again, it tries to open it further for some reason. When I gently press my finger against the door it slowly starts closing it, but that can't be right since it's way too slow, and after a few seconds it reverses and opens again (noisy, but with normal speed).
Unfortunately I see now that I miss one of the two springs holding that cover down (the one with the warnigs about laser radiation). I only have one installed on the right side, but it seems to have enough tension.
I also tried to find if anything got stuck or isn't aligned properly, but it all seems to be correct.
To fix the original issue, I found RonSSNova's post on page three:
Rotel RCD 855 repair
Could it be worth it to just try out if replacing those two transistors might solve it? My soldering skills are good enough for that. I'm not good at all at measuring things, and on top, my old meter started behaving funnily when I just wanted to use it to test the voltage of some AA batteries... showed some nonsensical numbers. I wanted to buy a good entry-level one anyways at some point, on mine I have to manually choose the measuring range and "Mr. EevBlog" (forgot how that guy's name is since I watched a bunch of his videos about a year ago) said that it's just cumbersome if a meter doesn't detect the correct measuring range automatically.
Thanks in advance 🙂
I have the same issue (disc rotating wrong way around), even after swapping the CDM 4/19 pickup as I suspected by earlier tips I got from German forums that it is most likely the culprit.
I verified that the "new" pickup worked by testing if the player (cheaper Philips one) worked, which it did. I wanted to test the unit from the Rotel inside the Philips, but I couldn't get it to work, but now I think that I connected something wrong since the plugs and sockets for the motors (spindle, tray) were different in between the two players. I've thrown the Philips player and the original unit from the Rotel out, since I moved a few months ago and since I though that original pickup was toast, anyways.
Now, as I again tried to get the Rotel back up with the "new" pickup (beforehand I also tried it but couldn't get anything to work, I didn't find the photos I took when first opening it so I assumed that I connected the wires wrongfully since there was one more socket on the PCB than necessary, between each attempt there were a few months were I didn't work on that issue at all) I connected everything correctly as documented by those photos, and, as mentioned before, the original issue persists.
And, I have a new issue. It wouldn't close the tray when I press the button, opening is fine, but way noisier than I remember. When it is open and I press the button again, it tries to open it further for some reason. When I gently press my finger against the door it slowly starts closing it, but that can't be right since it's way too slow, and after a few seconds it reverses and opens again (noisy, but with normal speed).
Unfortunately I see now that I miss one of the two springs holding that cover down (the one with the warnigs about laser radiation). I only have one installed on the right side, but it seems to have enough tension.
I also tried to find if anything got stuck or isn't aligned properly, but it all seems to be correct.
To fix the original issue, I found RonSSNova's post on page three:
Rotel RCD 855 repair
Could it be worth it to just try out if replacing those two transistors might solve it? My soldering skills are good enough for that. I'm not good at all at measuring things, and on top, my old meter started behaving funnily when I just wanted to use it to test the voltage of some AA batteries... showed some nonsensical numbers. I wanted to buy a good entry-level one anyways at some point, on mine I have to manually choose the measuring range and "Mr. EevBlog" (forgot how that guy's name is since I watched a bunch of his videos about a year ago) said that it's just cumbersome if a meter doesn't detect the correct measuring range automatically.
Thanks in advance 🙂
If the player has a long time then I would be looking at the mechanical side of things first, particularly if the drawer was OK when it was last used.
It also sounds like you might have a problem with any micro-switches not detecting when the drawer is fully open (and so letting you try and open it further).
Begin by checking all the mechanicals.
Swapping transistors just in hope probably isn't going to resolve this, although if the mechanics are sticking then the transistors could be overloaded suffer damage. Tbh voltage checks are the way to go. If the transistors are putting the correct supply voltage across the motor in each direction then they are going to be OK.
You do need a reliable meter but before condemning your old one try giving the probe tips a good clean. Also if your meter has a rotary type selector switch then try giving that a few good spins around and also clean the meters battery contacts.
It also sounds like you might have a problem with any micro-switches not detecting when the drawer is fully open (and so letting you try and open it further).
Begin by checking all the mechanicals.
Swapping transistors just in hope probably isn't going to resolve this, although if the mechanics are sticking then the transistors could be overloaded suffer damage. Tbh voltage checks are the way to go. If the transistors are putting the correct supply voltage across the motor in each direction then they are going to be OK.
You do need a reliable meter but before condemning your old one try giving the probe tips a good clean. Also if your meter has a rotary type selector switch then try giving that a few good spins around and also clean the meters battery contacts.
My 855 had a no spin up issue. Finger help would get CD started and play.
Changing those 2 transistors resolved the spin up issue. If you use alternatives, watch the terminal order.
955 service manual had laser setup. CDB 260 service manual , if I recalled correctly, had debug flowcharts with button presses.
Good luck
Changing those 2 transistors resolved the spin up issue. If you use alternatives, watch the terminal order.
955 service manual had laser setup. CDB 260 service manual , if I recalled correctly, had debug flowcharts with button presses.
Good luck