I picked up a Rotel RCD-855 that had a display & keypad that was non-functional. This was a result of the 15V Zener that failed. So I replaced all the Power Supply parts (diodes/regulators/zeners & capacitors) & electroylitic capacitors throughout the board. At the time prior to repairing the display/keyboard, the player worked intermittenly when using the remote control. The top clamp "washer' was loose and caused the disc to spin rough and as result the disc could not be read. I secured the clamp 'washer" and the player worked.
So after all the new parts were added the display was repaired and all the PS voltages are correct at all of the circuits that it was supplying.
So the player now goes into "ERR" (error mode) anytime I start up.
The following is what I have done since this initial "ERR" condition arose:
I soldered all of the joints throughout the player
I cleaned the laser lens outside & inside (removed the exterior lens cover).
I used a Philips CD-582 service manual and performed all the tests I could without the special service CD that it talks about. The results testing it in the "service Mode are:
The disc motor spins correctly, the radial arm back n forth and the laser focus mechanism moves up and down as required & the Laser LED emits a red light.
I measure the laser supply going to the laser (at 3.5VDC)
I soldered carefully all the solder joints on the laser wiring (foil interconnect)
I see the laser light ids functional. Not extemely bright - looking from an anle carefully.
I adjusted the 2 pots to see if there is any difference and no change for the better. The pots did affect operation accordingly but not any improvement to eliminate the error message.
What can I do next to diagnose the problem.....
Any input would be helpful...
Thanks in advance,
So after all the new parts were added the display was repaired and all the PS voltages are correct at all of the circuits that it was supplying.
So the player now goes into "ERR" (error mode) anytime I start up.
The following is what I have done since this initial "ERR" condition arose:
I soldered all of the joints throughout the player
I cleaned the laser lens outside & inside (removed the exterior lens cover).
I used a Philips CD-582 service manual and performed all the tests I could without the special service CD that it talks about. The results testing it in the "service Mode are:
The disc motor spins correctly, the radial arm back n forth and the laser focus mechanism moves up and down as required & the Laser LED emits a red light.
I measure the laser supply going to the laser (at 3.5VDC)
I soldered carefully all the solder joints on the laser wiring (foil interconnect)
I see the laser light ids functional. Not extemely bright - looking from an anle carefully.
I adjusted the 2 pots to see if there is any difference and no change for the better. The pots did affect operation accordingly but not any improvement to eliminate the error message.
What can I do next to diagnose the problem.....
Any input would be helpful...
Thanks in advance,
Forgot to mention:
Press PLAY button.... Disc will spin....... Display flashes with Play arrow and then within 3 seconds the "ERR" message displays....
Press PLAY button.... Disc will spin....... Display flashes with Play arrow and then within 3 seconds the "ERR" message displays....
It sounds like the laser is focusing, but can't read the table of contents. What error code did the player display in service mode?
Did you adjust them while monitoring the correct voltages? I know it a bit of a pig to do on this player, but if you don't your just feeling around in the dark.
Did you adjust them while monitoring the correct voltages? I know it a bit of a pig to do on this player, but if you don't your just feeling around in the dark.
It wouldn't give me an error code as I did not have the proper Service CD. I could only go so far for testing the drive "without the proper test CD".
So that is the problem... It won't read the TOC (Table of Contents).
So what causes this....
So that is the problem... It won't read the TOC (Table of Contents).
So what causes this....
I will try this tonight. Thanks for the tip as I thought you had to have a special SERVICE CD. I will let you know
Thanks,
Thanks,
Test Results:
I went into Test Service Mode "C" and went to Service Position 3 which will give you either "Music" or the other Path of Error Codes (by pressing Track Forward).
What happened is that extremely distorted unrecognizable "music" can be heard in a "CH -CH -CH -CH like almost like a "comb effect sound". The "music" goes up in volume and down accordingly & totally silent between tracks.
It won't allow me to go to next Service Position "E" (by pressing track forward), so I can't get any ERROR Codes.
So I don't know what I can do to get any more information.
So what would cause the music to be completely distorted....
One other note is that the foil interconnect from laser to circuit board is worn where the pins (on the board female connector) touch. So to eliminate this variable I did not insert the ribbon foil as far as I could normally inorder to get a better connection. Initially pushing on it when fully inserted caused the tracking (laser assembly to bang against each end and speed up). So ultimately to avoid this future condition, I may trim the foil ribbon to avoid this worn pin connection or solder pins to the ribbon and (remove female connection) and solder directly to the circuit board.
Any help would be appreciated.
Thanks in advance,
I went into Test Service Mode "C" and went to Service Position 3 which will give you either "Music" or the other Path of Error Codes (by pressing Track Forward).
What happened is that extremely distorted unrecognizable "music" can be heard in a "CH -CH -CH -CH like almost like a "comb effect sound". The "music" goes up in volume and down accordingly & totally silent between tracks.
It won't allow me to go to next Service Position "E" (by pressing track forward), so I can't get any ERROR Codes.
So I don't know what I can do to get any more information.
So what would cause the music to be completely distorted....
One other note is that the foil interconnect from laser to circuit board is worn where the pins (on the board female connector) touch. So to eliminate this variable I did not insert the ribbon foil as far as I could normally inorder to get a better connection. Initially pushing on it when fully inserted caused the tracking (laser assembly to bang against each end and speed up). So ultimately to avoid this future condition, I may trim the foil ribbon to avoid this worn pin connection or solder pins to the ribbon and (remove female connection) and solder directly to the circuit board.
Any help would be appreciated.
Thanks in advance,
Put a disc in, start the player in service mode and press play. I think this should give you an error code.
It sounds to me like it is focusing and reading, but not tracking correctly. With the player off, how free is the movement of the radial arm when you bump it? Does it move freely right to either end of it's track?
It sounds to me like it is focusing and reading, but not tracking correctly. With the player off, how free is the movement of the radial arm when you bump it? Does it move freely right to either end of it's track?
Error code 7
It gives me ERROR CODE 7 which is "Subcoding Error during Play (Check HF).
So how do I check HF? I will check service manual as well.....
It gives me ERROR CODE 7 which is "Subcoding Error during Play (Check HF).
So how do I check HF? I will check service manual as well.....
Radial arm movement is good (freely moves with minimal effort & as well in Service Mode B - No disc & Search forward & Back button pressed and the arms goes to each extreme) & laser focus is functional (vertical movement in Service Mode B Position 1) as well as LED is visible in same mode.
So HF.....looking at the Block Diagram involves the Photodiodes & TDA 8088 & SAA7210.
As a side note:
I have modified this unit to a Non-OverSampling unit with 3 traces cut between SAA7220B & TDA1541A (Connections between Pin 18/16/15 on SAA722B
(Terminals 1/2/3 on 1541A) and connect directly from SAA7210 37/38/39 to 3/2/1 respectively on TDA1541A. To maintain the MUTE function I connected from Pin 11 on SAA7210 to Pin 23 on SAA7220B.These connection were triple checked for accuracy.
So HF.....looking at the Block Diagram involves the Photodiodes & TDA 8088 & SAA7210.
As a side note:
I have modified this unit to a Non-OverSampling unit with 3 traces cut between SAA7220B & TDA1541A (Connections between Pin 18/16/15 on SAA722B
(Terminals 1/2/3 on 1541A) and connect directly from SAA7210 37/38/39 to 3/2/1 respectively on TDA1541A. To maintain the MUTE function I connected from Pin 11 on SAA7210 to Pin 23 on SAA7220B.These connection were triple checked for accuracy.
Yep, the first thing I would look at is that shonky ribbon connection. The photodiode signals go right through that. Do you have a spare CDM-4/19 to check with?
I purchased a 2nd 855, that will arrive by the end of the week.
I will swap out the existing CDM4 drive then I will let you know the results.
I am hoping it is the drive (specifically the laser unit) versus the mainboard as I spent a few bucks changing out most of the PS parts as well as adding dual PA627 modules in the output stage. As well the total changout of all PS decoupling caps throughout the whole board with Low ESR caps throughout all circuits except the output stage where I used Nichicon Muse FG for decoupling and Muse ES BP in the coupling to output. I also removed the 4 muting transistors as well making it a NON-Oversampling Player bypassing the 4X OS Digital Filter SAA7220B.
I will let you know my findings. I will continue to research the "HF" failure as indicated by ERROR Code 7.
Thanks again,
I will swap out the existing CDM4 drive then I will let you know the results.
I am hoping it is the drive (specifically the laser unit) versus the mainboard as I spent a few bucks changing out most of the PS parts as well as adding dual PA627 modules in the output stage. As well the total changout of all PS decoupling caps throughout the whole board with Low ESR caps throughout all circuits except the output stage where I used Nichicon Muse FG for decoupling and Muse ES BP in the coupling to output. I also removed the 4 muting transistors as well making it a NON-Oversampling Player bypassing the 4X OS Digital Filter SAA7220B.
I will let you know my findings. I will continue to research the "HF" failure as indicated by ERROR Code 7.
Thanks again,
Swapped out the transport with another and same problem.....
As you were aware I changed out all my electrolytic capacitors and I can't even get to the TOC. It will spin for 5 seconds or so and show Error on display.
I picked up another 855 that was dead. The 5V regulator had failed. Now I replaced the regulator and it works fine.
So I swapped out complete transport drive and put this 2nd unit in the 1st unit and I have exactly the same problem.
Put the 1st transport into 2nd player and it works fine, so this eliminates the transport and so the main board is determined to be at fault.
Firstly in Service Mode and press Play, I get Error 7 which state "HF /subcode missing"
So put it in Service Mode again and (Pause/Repeat/FF) to get the "P105" service mode. I press Forward Track 3 times to get the player to try to play music.
It will play music 1-2% of the time and the rest sounds like chopped/sliced bits of music completely distorted and unrecognizable. It sounds like ch-ch-ch-ch at the same speed as the music....
I resoldered every connection on the board and checked for solder bridges as well. Any ideas?
You mentioned checking for trace damage and I will try that again.
I followed the HF signal via close examination from the ribbon connector (on the main board to the TDA8088 to SAA7210 (HF signal) and back to TDA8088 (HFD
signal) and it looks good (Soldered all the these components and all the pins that are part of this circuit.
Could it be the Servo system is so poor that it can't even generate the TOC. It seems to be extremely sensitive to vibration and it will lose track and begin to go in reverse at warp speed.
Let me know.
Thanks,
As you were aware I changed out all my electrolytic capacitors and I can't even get to the TOC. It will spin for 5 seconds or so and show Error on display.
I picked up another 855 that was dead. The 5V regulator had failed. Now I replaced the regulator and it works fine.
So I swapped out complete transport drive and put this 2nd unit in the 1st unit and I have exactly the same problem.
Put the 1st transport into 2nd player and it works fine, so this eliminates the transport and so the main board is determined to be at fault.
Firstly in Service Mode and press Play, I get Error 7 which state "HF /subcode missing"
So put it in Service Mode again and (Pause/Repeat/FF) to get the "P105" service mode. I press Forward Track 3 times to get the player to try to play music.
It will play music 1-2% of the time and the rest sounds like chopped/sliced bits of music completely distorted and unrecognizable. It sounds like ch-ch-ch-ch at the same speed as the music....
I resoldered every connection on the board and checked for solder bridges as well. Any ideas?
You mentioned checking for trace damage and I will try that again.
I followed the HF signal via close examination from the ribbon connector (on the main board to the TDA8088 to SAA7210 (HF signal) and back to TDA8088 (HFD
signal) and it looks good (Soldered all the these components and all the pins that are part of this circuit.
Could it be the Servo system is so poor that it can't even generate the TOC. It seems to be extremely sensitive to vibration and it will lose track and begin to go in reverse at warp speed.
Let me know.
Thanks,
At least some things are easily fixed, huh!
I'm starting to wonder if you have some sort of motor control or clock problem. No matter how badly the player is reading a disk, it should never go into reverse like that. What is the rotation speed of the spindle when the bad player is trying to play music in test mode? Compare it with your good RCD855.
Sensitivity to vibration is a big indicator of faulty soldering. The soldering on my own RCD855 was abysmal (shame on you Rotel), a whole regulator had cracked off the PCB, a cracked trace had been badly repaired, along with many other factory faults.
I'd check two sections in particular:
- The SAA7210 and its crystal. A loss of clock will cause uncontrolled spindle rotation.
- The spindle motor drive (especially the discrete BJT stage).
Describe this loss of spindle motor control in more detail. Once it is set off by vibration, does it continue until the player is powered off then on? If so, I would really have a good look at the clock, as a loss of clock during play will do exactly this.
Fixed!!!!!!!!!!!!!!
Voila!!!! I did the same thing as I put a 47uF ESR 25V cap on the Pin 22 of SAA7220 on Rotel 855 player instead of a 2.2uF standard cap (I thought it was a 22uF so I installed a 47uF assuming it was a PS decoupling cap!). It probably didn't have a chance to work when the impedance presented to Pin 22 was probably at least 100X less and played Havoc with the circuit!
Next time I am going to make sure that these caps are functioning as PS decoupling!
Thanks mag2211 and AMC (Anton)!!!!!!
Voila!!!! I did the same thing as I put a 47uF ESR 25V cap on the Pin 22 of SAA7220 on Rotel 855 player instead of a 2.2uF standard cap (I thought it was a 22uF so I installed a 47uF assuming it was a PS decoupling cap!). It probably didn't have a chance to work when the impedance presented to Pin 22 was probably at least 100X less and played Havoc with the circuit!
Next time I am going to make sure that these caps are functioning as PS decoupling!
Thanks mag2211 and AMC (Anton)!!!!!!
R108 Adjustment
In case anyone comes to this thread a long time after it seemingly ended in 2010 - as I did today, I have discovered an *easy* fix for an RCD-855 which would not read the TOC of a CD and would not play, resulting in the red "Error" display in the front panel window.
The fix consisted of adjustment of R108, a pot on the main board just left of the transport mechanism (which I read somewhere controls the power to the laser - increasing with CW rotation). It was necessary to use small plastic hex alignment tool (GC/Waldom Alignment Tool Kit available from Techni-Tool). I was perhaps lucky to hit the sweet spot on the pot on the sixth or seventh try...took less than five minutes. I imagine mileage may vary on this, but I found the sweet spot near full CCW rotation.
It's a joy to have this player back. Good luck!
RC in VT
In case anyone comes to this thread a long time after it seemingly ended in 2010 - as I did today, I have discovered an *easy* fix for an RCD-855 which would not read the TOC of a CD and would not play, resulting in the red "Error" display in the front panel window.
The fix consisted of adjustment of R108, a pot on the main board just left of the transport mechanism (which I read somewhere controls the power to the laser - increasing with CW rotation). It was necessary to use small plastic hex alignment tool (GC/Waldom Alignment Tool Kit available from Techni-Tool). I was perhaps lucky to hit the sweet spot on the pot on the sixth or seventh try...took less than five minutes. I imagine mileage may vary on this, but I found the sweet spot near full CCW rotation.
It's a joy to have this player back. Good luck!
RC in VT
Thanks heybobo for writing the previous post. It helped me.
I first had a no spin issue. Aiding the CD during TOC read made it work. So I changed transistors T102, T103. This fixed the no spin issue.
I tried a couple of different NOS mods. No success. Went back to stock. In all three cases, spins, no TOC.
Then I remembered this thread. I changed R108 a small amount and it is functional again. 🙂
I am pleasantly surprised how nice this sounds to me.
And this player has a TDA1541A . Not the single crown S1 as most websites list.
I first had a no spin issue. Aiding the CD during TOC read made it work. So I changed transistors T102, T103. This fixed the no spin issue.
I tried a couple of different NOS mods. No success. Went back to stock. In all three cases, spins, no TOC.
Then I remembered this thread. I changed R108 a small amount and it is functional again. 🙂
I am pleasantly surprised how nice this sounds to me.
And this player has a TDA1541A . Not the single crown S1 as most websites list.
Hi guys, I did (stupidly) the NOS mod to my two working RCD855s and now they both don't work, no TOC, adjusted trim pots to rectify but now no audio output - I took the mod off and still no audio out. What could I have done wrong? I cut the tracks near pins 1,2 & 3 on the 1541A and SAA7220 and joined pin 1 to 1, 2 to 2 and 3 to 3. A previous mod I tried was to just desolder the pins and join with wire but this just blew a rail. Help! I got two dead CDPS. Mr H also had the same instructions as you.
Hi phildela,
Well, you could have killed them with static electricity I guess. First things first, get a good strong light and desolder your connections, everything you did. Clean the area up, and if you have any liquid solder flux (for electronics), dab a little on each connection point and try to solder it together. You may have to use a little piece of wire. Don't get creative, connect things as they were.
After soldering the connections, clean the flux away from all the connections carefully. You can use lacquer thinner on a "Q-Tip" to carefully dissolve the flux and clear it away. Do not scrub.
Once you are certain your connections are good, you can turn the unit on and check that it doesn't blow any fuses or resistors. Leave it on to see if any of the chips start to get hot.
So, why would anyone attempt to perform a non-oversampling "mod" to a perfectly good CD player in the first place. I know you don't have a 7th order low pass filter to install, and that is exactly what you need to keep the 44.1 KHz out of your audio system. This is fairly important, because the carrier (that's what it has become) will be able to get through most electronics and distress the tweeter. Even if it doesn't get that far, this tone can cause the electronics in preamps and amplifiers to become clipped or non-linear. I can't stress enough how this is such a poor practice. That and the wholesale destruction of so many innocent CD players. This really is a job for a trained technician to perform (if they will).
Now, because you have adjusted the trimmer controls, you made it so a technician is required to get it working (never touch those things!!!!). It is possible that if you cranked the APC pot up, you could have baked the laser head. And the next one that someone tries. So if you do take these to a technician, be completely honest with them so that they don't blow something up due to the non-standard settings on those controls.
I am really sorry I don't have better news for you, but I am being honest. If there was something I could talk you through, I would recommend it. The second you touched the trimmer controls, you made it a technician only job. If you aren't going to take them to a technician, just run over them with a car or truck. The end result will be similar, except you had fun running them over.
-Chris
Well, you could have killed them with static electricity I guess. First things first, get a good strong light and desolder your connections, everything you did. Clean the area up, and if you have any liquid solder flux (for electronics), dab a little on each connection point and try to solder it together. You may have to use a little piece of wire. Don't get creative, connect things as they were.
After soldering the connections, clean the flux away from all the connections carefully. You can use lacquer thinner on a "Q-Tip" to carefully dissolve the flux and clear it away. Do not scrub.
Once you are certain your connections are good, you can turn the unit on and check that it doesn't blow any fuses or resistors. Leave it on to see if any of the chips start to get hot.
So, why would anyone attempt to perform a non-oversampling "mod" to a perfectly good CD player in the first place. I know you don't have a 7th order low pass filter to install, and that is exactly what you need to keep the 44.1 KHz out of your audio system. This is fairly important, because the carrier (that's what it has become) will be able to get through most electronics and distress the tweeter. Even if it doesn't get that far, this tone can cause the electronics in preamps and amplifiers to become clipped or non-linear. I can't stress enough how this is such a poor practice. That and the wholesale destruction of so many innocent CD players. This really is a job for a trained technician to perform (if they will).
Now, because you have adjusted the trimmer controls, you made it so a technician is required to get it working (never touch those things!!!!). It is possible that if you cranked the APC pot up, you could have baked the laser head. And the next one that someone tries. So if you do take these to a technician, be completely honest with them so that they don't blow something up due to the non-standard settings on those controls.
I am really sorry I don't have better news for you, but I am being honest. If there was something I could talk you through, I would recommend it. The second you touched the trimmer controls, you made it a technician only job. If you aren't going to take them to a technician, just run over them with a car or truck. The end result will be similar, except you had fun running them over.
-Chris
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