Hello Matthias:
You´ve got mail.
Hello anatech, sorry, I´ll have to ask (again) some dumb questions:
I did the tuning of focus and tracking by "try and error", without any additional devices, just using some defective CDs.
But I now found out, I did tune focus/tracking gain way too low.
(Nak jumps on vibrations)
So I would like do tune according to the service manual, because I can not clearly distinguish high frequency noise from low frequency noise on my scope as you described some time ago and I hope, Nakamichi´s standard procedure will help.
By the way, who did translate the procedure from Japanese????
My questions:
220kohm in series means a resistor soldered in the path of the "hot"signal wire?
Or bridging ground and signal of the wire?
Then lowering the output volume of my "oscillator" (generated sine tone from the Pc´s soundcard or any other device (earphone Jack of DAT or a second Player playing the sine tone) until I measure 300mv AC?
I can only display mV on the DC setting of my 5$ Voltmeter, does this equal 150 mV DC?
And finally indeed solder my custom made signal cable to pin4 of U 102?
AND put a band-pass filter (BPF???) between oscilloscope and the test pin "Track"?
Will there be a shift in phase, when I tune RV103, this is why I need a filter?
And where do I get one?
The procedure is still attached to my earlier post, thanks in advance...
All the best,
Salar
You´ve got mail.
Hello anatech, sorry, I´ll have to ask (again) some dumb questions:
I did the tuning of focus and tracking by "try and error", without any additional devices, just using some defective CDs.
But I now found out, I did tune focus/tracking gain way too low.
(Nak jumps on vibrations)
So I would like do tune according to the service manual, because I can not clearly distinguish high frequency noise from low frequency noise on my scope as you described some time ago and I hope, Nakamichi´s standard procedure will help.
By the way, who did translate the procedure from Japanese????
My questions:
220kohm in series means a resistor soldered in the path of the "hot"signal wire?
Or bridging ground and signal of the wire?
Then lowering the output volume of my "oscillator" (generated sine tone from the Pc´s soundcard or any other device (earphone Jack of DAT or a second Player playing the sine tone) until I measure 300mv AC?
I can only display mV on the DC setting of my 5$ Voltmeter, does this equal 150 mV DC?
And finally indeed solder my custom made signal cable to pin4 of U 102?
AND put a band-pass filter (BPF???) between oscilloscope and the test pin "Track"?
Will there be a shift in phase, when I tune RV103, this is why I need a filter?
And where do I get one?
The procedure is still attached to my earlier post, thanks in advance...
All the best,
Salar
Hi Salar,
Sorry for the long time to reply. I hope this is helpful to you still ...
How did you do on your player?
-Chris
Sorry for the long time to reply. I hope this is helpful to you still ...
Yes, Nakamichi uses an NEC head with custom servos. You pretty much have to follow the service manual.
I wish I knew. It's obvious that many companies used the same place though.
Yes.
No.
No, you need to set for an AC value. This is where a digital voltmeter is at a strong disadvantage. An AC voltmeter or VTVM is a better instrument. You can use an oscilloscope if you convert to peak - to - peak voltages and measure that way. A calibrated VTVM is often more accurate than a normal oscilloscope.
Yes.
No, you are measuring a voltage level. They are reducing the noise to get you a more accurate reading. Normally, any required filters are detailed in the manual. Should be near the start of the "Adjustments" section. It's been a very long time since I have looked at this. When I do these, I run off memory and whatever information I have at hand.
How did you do on your player?
-Chris
Hello Chris,
thank you for your reply. I hope, you are doing well.
I did not succeed so much, because perfect alignment is beyond my knowledge.
You once told me about the high frequency an low frequency components I would see on the scope while adjusting without any additional means.
But I can not judge what I see on the scope.
When I built a digital output for the Nak, I did buy the service manual for Sony 552ESD, which uses the same RF-Amp(CX20109) and Digital L.S.I. (CX23035), but different laser (KSS-151) I guess.
In the Sony, adjusting the tracking gain is much more simple, only a CD with defects is needed...
All the best,
Salar
thank you for your reply. I hope, you are doing well.
I did not succeed so much, because perfect alignment is beyond my knowledge.
You once told me about the high frequency an low frequency components I would see on the scope while adjusting without any additional means.
But I can not judge what I see on the scope.
When I built a digital output for the Nak, I did buy the service manual for Sony 552ESD, which uses the same RF-Amp(CX20109) and Digital L.S.I. (CX23035), but different laser (KSS-151) I guess.
In the Sony, adjusting the tracking gain is much more simple, only a CD with defects is needed...
All the best,
Salar
Hi Salar,
Yes, the Nakamichi is more difficult to set up. Remember that I mention it took be about 5 hours to perform the checks and circuit changes, clean and align the head block (changing the head or not) and then setting up the servos. Mind you, they worked wonderfully after that treatment. Much better than new.
The mechanical head alignment is critical. If you have problems there, don't expect to correct them with the servos. Once aligned, the performance will be better than anything you have ever seen before
-Chris
Yes, the Nakamichi is more difficult to set up. Remember that I mention it took be about 5 hours to perform the checks and circuit changes, clean and align the head block (changing the head or not) and then setting up the servos. Mind you, they worked wonderfully after that treatment. Much better than new.
The mechanical head alignment is critical. If you have problems there, don't expect to correct them with the servos. Once aligned, the performance will be better than anything you have ever seen before
-Chris
Hi anatech,
I guess, you are talking about the OMS 5/7 models here, not the 5/7II? The mark I models have a mechanical alignment of the heads, the mark II models do not.
Just looked at the service manual for the mark I models, a technician has much more possibilities for alignment than in the mark II models.
I do not remember if i had sent the SM of both models to you...
Playing around with the tracking gain does not show much differnce on my OMS-5II, and I have 3 brand pickups (bought around 2000 and safely stored since then) to try the setup with. (no sticky heads) Because I did replace the disc motor as well (with an additiional brass bearing in the spacer for the shaft oft the motor, no mechanical play there), I bought faster types of the transistors in the servo circuitry, maybe I give them a try during xmas. But I guess, the original ones are already fast enough and deliver enough current...?
All the best,
Salar
I guess, you are talking about the OMS 5/7 models here, not the 5/7II? The mark I models have a mechanical alignment of the heads, the mark II models do not.
Just looked at the service manual for the mark I models, a technician has much more possibilities for alignment than in the mark II models.
I do not remember if i had sent the SM of both models to you...
Playing around with the tracking gain does not show much differnce on my OMS-5II, and I have 3 brand pickups (bought around 2000 and safely stored since then) to try the setup with. (no sticky heads) Because I did replace the disc motor as well (with an additiional brass bearing in the spacer for the shaft oft the motor, no mechanical play there), I bought faster types of the transistors in the servo circuitry, maybe I give them a try during xmas. But I guess, the original ones are already fast enough and deliver enough current...?
All the best,
Salar
Hi Salar,
I think you sent me one manual, I'll have to look to see which one I have.
Playing around with the tracking gain does not show much differnce on my OMS-5II
Those are three beam NEC heads (the OMS-5 / 7 uses an NEC single beam system). Still, the servos should show low frequency components when the gain is too low, and high frequency components when the gain is too high.
-Chris
Yes I am actually. Alignment on the original models is far more complicated, and far more rewarding. The type II models have a better D/A I think. I didn't care for the simplified mechanism too much. Still, better than the KSS-210A type transports. Same motor though.
I think you sent me one manual, I'll have to look to see which one I have.
Those heads can go bad sitting in there box. It's happened to me.
If those transistors in the servo are good, leave them alone. The servos run at audio frequencies, almost any transistor will have much higher frequency response than required here. Replacing these parts might be an invitation to trouble. These circuits were carefully designed, so I don't expect there are any short comings with the original parts.
Playing around with the tracking gain does not show much differnce on my OMS-5II
Those are three beam NEC heads (the OMS-5 / 7 uses an NEC single beam system). Still, the servos should show low frequency components when the gain is too low, and high frequency components when the gain is too high.
-Chris
I found these links to test cd:s
As noted earlier in this thread there are different kinds of test cd:s, some are "perfect" cd's with various test sounds that could be used for calibrating tracking and gain etc. Other test cd's have specific manufactured errors (skewed/wobbly tracks, missing data, holes, "fingerprints") etc and are used to test that your reader behaves in certain various expected ways when they encounter those errors.
If you use the images below to burn your own test cd:s you will have something like the first kind of test discs described, however they are not guaranteed to be as precise as original purchased engineering test cds. I would recommend burning at the lowest possible speed for best fidelity.
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-andreas
As noted earlier in this thread there are different kinds of test cd:s, some are "perfect" cd's with various test sounds that could be used for calibrating tracking and gain etc. Other test cd's have specific manufactured errors (skewed/wobbly tracks, missing data, holes, "fingerprints") etc and are used to test that your reader behaves in certain various expected ways when they encounter those errors.
If you use the images below to burn your own test cd:s you will have something like the first kind of test discs described, however they are not guaranteed to be as precise as original purchased engineering test cds. I would recommend burning at the lowest possible speed for best fidelity.
RapidShare: 1-CLICK Web hosting - Easy Filehosting
RapidShare: 1-CLICK Web hosting - Easy Filehosting
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-andreas
Depends on what is called for. Are you able to find a track listing for the above test cds? My service manual for my Pioneer DJM-500 players called for track 20 on a Sony YEDS-7 disc, but also stated that what was needed was a 1kHz sine signal at -60dB so I was able to find a track just like this at track 17 on the YEDS-18 (Rapidshare link to this test cd in two messages above)
By the way I found that the RARs for the Sheffield test disc were password-encrypted, I googled around a bit and found the password; it is "www.AvaxHome.ru"
You will find that these discs are packed in two different lossless-compression formats. The first is in FLAC format, just google FLAC and you will find the software to decode it to WAVs (which you could then burn)
The second is encoded with Monkey's Audio (extension .APE) I used Monkeys Audio to uncompress the file into a single WAV and then edited the .CUE-sheet to reference the WAV instead of the APE, then I used my normal burning software to burn the image from the .CUE-sheet.
You might find it a bit cumbersome to download files from Rapidshare, I would recommend using the "Rapidshare auto downloader" from Automatic Download from Rapidshare.com which basically is a software that retries the requested downloads until they are recieved.
-andreas
Andreas, I will have to check my troubleshooting guide when I get home. But as far as these links go, I thought based on what was said further up in this thread that part of what's critical here is the actual disc, that burning a disc with the ripped tracks wouldn't guarantee the right accuracy, eye pattern etc. Sounds like it could do more harm than good if you don't get a good copy.
Hi tonyptony,
I've said this so many times in the past that I'm really sick and tired of saying the same thing over and over.
Okay people, this is the brutal truth about test discs. Point form and I may miss a couple ...
I've tried to give you the reasons why these burned test discs will not work for you. In fact, they will mislead you. So, you really do need to buy a proper Test CD in order to adjust anything in the servo section in a CD player. The very last thing you should ever touch are the adjustments. In fact, consider that your CD player operated fine for years using those adjustment settings. If they should be out some, it will not be by very much. Well, they shouldn't be far off. Depends on how may have been in there before you.
My advice? Unless you have the right tools, test equipment and knowledge. Otherwise you may very well make things much worse than they are.
Sorry for the bad news.
-Chris
You are exactly correct.
I've said this so many times in the past that I'm really sick and tired of saying the same thing over and over.
Okay people, this is the brutal truth about test discs. Point form and I may miss a couple ...
- Reflectivity - The information layer is partly translucent with varying degrees of reflectivity. This will change the amplitude of the RF waveform and may even cause the laser output to be higher. Useless.
- Reflectivity again - Will alter the "slice level" and may even be asymmetrical! Often the RF waveform ends up very distorted. Extracting information from this situation is problematic at best. The "slice level" is an old manual adjustment that Yamaha and others had. It determines where the zero level will be interpreted to sense zero crossings. Newer chip sets do this using internal servos. They are easily mislead. A side issue is higher error rates
- Pit Shape - Well defined pit / land areas in the information track determines how "clean" the Eye Pattern will look. It also may be bad enough to run the focus and tracking servos harder. Information obtained by using a "copied" test CD area waste of time due to this.
- Pit Shape again - Poor RF patterns increase the error rate, and may even prevent the disc motor speed servo (PLL) from obtaining lock. The Focus and Tracking servos will also be running too hard, maybe causing the gains to be set to the acquire mode. That's higher than the normal "locked and running" mode.
- Eccentricity - Quality pressed CDs are normally closer to "Redbook" (I hate that term) standards. Therefore, servo gains can be adjusted with a selected pressed CD. Recordable CDs are fundamentally different from normal, pressed CDs and gains set with these will be wrong.
- Defects - Defects placed onto or inside the data layers can not be duplicated using a CD writer. The old Philips 5A test disc begins life as a Philips 5 test disc. Defects are then mechanically printed on the reading surface, making it a Philips 5A. These markings are fragile and can be damaged very easily. For $250 I expected much better! The better CDs have these defects right in the information layer, so they are even more precise.
I've tried to give you the reasons why these burned test discs will not work for you. In fact, they will mislead you. So, you really do need to buy a proper Test CD in order to adjust anything in the servo section in a CD player. The very last thing you should ever touch are the adjustments. In fact, consider that your CD player operated fine for years using those adjustment settings. If they should be out some, it will not be by very much. Well, they shouldn't be far off. Depends on how may have been in there before you.
My advice? Unless you have the right tools, test equipment and knowledge. Otherwise you may very well make things much worse than they are.
Sorry for the bad news.
-Chris
Unfortunately I am at that point. Chris, I don't suppose you'd know if the Philips Disc 5 is the same as the old Philips Audio Signals Disc 1?
What I'd give for an English translation of a Philips CDM1 Mk.II service and adjustment manual.
Hi tonyptony,
Well, those controls probably have a small dent in the carbon track. If you move the wiper very gently, you might be able to feel the contact point fall into it.
I had some Revox machines to do once that had a really odd problem. The suspension sagged over time. The end result was that I had a choice. Adjust so the CD would read but wouldn't play, or adjust so that it would play, but not be able to find the disc. The only fix was a new CDM from Revox. I think they went for $900 or so at the time. Pure robbery. Oh!, you didn't know about the focus height adjustment? It's a mechanical adjustment in the head swing arm. It's also a real pain and not likely to result in a happy technician.
I don't recall if I ever saw a PDF file on that transport, but <hint!> if you look up an early Revox CD player, you may possibly find some helpful information in there. There may be other service manuals that can help as well (other brands). Most of these transports were basically the same with differing options. Even the disc motor type has two options I think. Brushless direct drive, or the more common brush type motor. The brushless motor is a larger PCB type assembly, but it does fit. I'm sure the servo has some changes on it as well.
-Chris
Well, those controls probably have a small dent in the carbon track. If you move the wiper very gently, you might be able to feel the contact point fall into it.
I had some Revox machines to do once that had a really odd problem. The suspension sagged over time. The end result was that I had a choice. Adjust so the CD would read but wouldn't play, or adjust so that it would play, but not be able to find the disc. The only fix was a new CDM from Revox. I think they went for $900 or so at the time. Pure robbery. Oh!, you didn't know about the focus height adjustment? It's a mechanical adjustment in the head swing arm. It's also a real pain and not likely to result in a happy technician.
I don't recall if I ever saw a PDF file on that transport, but <hint!> if you look up an early Revox CD player, you may possibly find some helpful information in there. There may be other service manuals that can help as well (other brands). Most of these transports were basically the same with differing options. Even the disc motor type has two options I think. Brushless direct drive, or the more common brush type motor. The brushless motor is a larger PCB type assembly, but it does fit. I'm sure the servo has some changes on it as well.
-Chris
Hi tonyptony,
I'm in Canada and I'm offering to help you if you're ever in the area!
I hear you there.
No, the earlier Revox. The 226 make have had a warping loader frame, I can't remember exactly. The casting actually warped in a way to close up the path for the tray guide. The fix was to file it open ( - no). That's what I was told to do. The fix would have been to add external support to hold it open.
I can't remember which machines used which transport these days. That was something that I knew 15 years ago and it became "mind garbage". I did see the odd web site that did list transports and transports. I think they also list which DACs these machines use as well. No harm in looking as long as it doesn't cost you for the download.
-Chris
I'm in Canada and I'm offering to help you if you're ever in the area!
I hear you there.No, the earlier Revox. The 226 make have had a warping loader frame, I can't remember exactly. The casting actually warped in a way to close up the path for the tray guide. The fix was to file it open ( - no). That's what I was told to do. The fix would have been to add external support to hold it open.
I can't remember which machines used which transport these days. That was something that I knew 15 years ago and it became "mind garbage". I did see the odd web site that did list transports and transports. I think they also list which DACs these machines use as well. No harm in looking as long as it doesn't cost you for the download.
-Chris