Hi Roland,
Some times the jigs are needed to get things in the ballpark. I use some tricks to fine tune the servos, but this is experience and a couple defect test CDs no longer available.
I wouldn't say the test jigs are not needed as I have experienced a couple that were absolutely required. Your service manual might have the information needed to construct the jig you are talking about.
Re: RF offset. What Mooly has suggested is probably what your problem was.
-Chris
Some times the jigs are needed to get things in the ballpark. I use some tricks to fine tune the servos, but this is experience and a couple defect test CDs no longer available.
I wouldn't say the test jigs are not needed as I have experienced a couple that were absolutely required. Your service manual might have the information needed to construct the jig you are talking about.
Re: RF offset. What Mooly has suggested is probably what your problem was.
-Chris
Well it's too late for the VCO cause I already checked it with my frequency counter and it was pretty much dead on. It called for a reading of 4.32 Mhz. I used a small plastic screwdriver and slightly adjusted the coil to see how sensitive it was. It was quite easy to adjust.
I did try adjusting the focus and tangential offset which is what you call the focus bias. The tangential offset on mine is a big plastic hex screw with a spring on it to keep the tension and my focus offset is a trim pot. I took my very fine tip marker and marked them so I could turn the back to their original set point and experimented. As you said, the manual has a picture of what it should look like and requires to adjust for maximum amplitude and a clean, non blurry diamond pattern which it was. I played with it and got the best results where the original setting was at.
Learning more and more with every post!
This is great fun for me!!!
Roland
Thanks Chris!
Unfortunately, the service manual has no information on the making of the test jig at least not that I've noticed.
As far as the offset goes, I think I tried everything with my scope but just could not get a reading. But I am persistent and will figure it out somehow!
Roland
Hi Roland,
The frequency adjustment usually has you short the EFM test point, but do not do this unless the manual instructs you to do that. Your frequency just might be wayyy off now.
Sometimes knowing what is expected can fill in the blanks when reading skimpy service manuals.
-Chris
The frequency adjustment usually has you short the EFM test point, but do not do this unless the manual instructs you to do that. Your frequency just might be wayyy off now.
Sometimes knowing what is expected can fill in the blanks when reading skimpy service manuals.
-Chris
The tangential adjustment with a spring is a mechanical adjustment and (normally) is factory set. Diffraction grating adjustment is another nightmare one.
The VCO. What Chris is saying is that the reading will always appear spot on when its playing a disc and the servos are locked. What the adjustment entails is getting its free run frequency to be correct so that it can 'lock in' easily and for that there could be a specific procedure.
The VCO. What Chris is saying is that the reading will always appear spot on when its playing a disc and the servos are locked. What the adjustment entails is getting its free run frequency to be correct so that it can 'lock in' easily and for that there could be a specific procedure.
The VCO check was the very first test in the service manual and was straight forward. It said to to hook up a frequency counter to TP1 ground and TP2 PLCK with player in stop mode and verify that it's 4.32 Mhz which is what I did. It was pretty much spot on!
Ah, OK. That's specific and correct.
You might this interesting... don't take it all as absolute fact but its a good read.
Notes on the Troubleshooting and Repair of Compact Disc Players and CDROM Drives
You might this interesting... don't take it all as absolute fact but its a good read.
Notes on the Troubleshooting and Repair of Compact Disc Players and CDROM Drives
Hi Mooly,
I really, really wish that folks would not write that type of article. I spotted many errors right off the bat. Does this guy actually use test equipment, or does he just write about it?
It is bloody easy to destroy a laser head by cleaning it for example. Physically - never mind the wrong cleaning solution or applicator. He missed problem #1 (disc motor) completely for example. The fact that this is a precision adjustment (height) should stop most people in their tracks. I hope anyway.
The one thing I do agree with is that there are too many incompetent repair people out there, but there are a lot of good ones. The article gave me the impression that the entire service industry is a scam. That does a great disservice to all those techs that endeavor to do a really good job.
-Chris
I really, really wish that folks would not write that type of article. I spotted many errors right off the bat. Does this guy actually use test equipment, or does he just write about it?
It is bloody easy to destroy a laser head by cleaning it for example. Physically - never mind the wrong cleaning solution or applicator. He missed problem #1 (disc motor) completely for example. The fact that this is a precision adjustment (height) should stop most people in their tracks. I hope anyway.
The one thing I do agree with is that there are too many incompetent repair people out there, but there are a lot of good ones. The article gave me the impression that the entire service industry is a scam. That does a great disservice to all those techs that endeavor to do a really good job.
-Chris
I have seen that site before but I'm not knowledgeable enough to even come close to making an assessment....lol
As far as defraction grating goes, my service manual does have the complete procedure for adjusting but I'm not even sure where the heck the adjustment is. The manual mentions the pick-up adjusting hole and to use a grid driver. I'll have to take a real close look at that. The manual has a flow chart to verify if the defraction grating needs to be adjusted but unless it's really off then I will leave alone. I have a brand new laser pick-up that I was lucky enough to get from Kenwood a couple years ago that will be going into my DP-3300 when I rebuild that unit. I assume that the defraction grating in that pick-up was factory set so I don't need to adjust.
As far as defraction grating goes, my service manual does have the complete procedure for adjusting but I'm not even sure where the heck the adjustment is. The manual mentions the pick-up adjusting hole and to use a grid driver. I'll have to take a real close look at that. The manual has a flow chart to verify if the defraction grating needs to be adjusted but unless it's really off then I will leave alone. I have a brand new laser pick-up that I was lucky enough to get from Kenwood a couple years ago that will be going into my DP-3300 when I rebuild that unit. I assume that the defraction grating in that pick-up was factory set so I don't need to adjust.
Hey Chris!
When you mention that it's easy to destroy a laser head by cleaning, are you talking about the focus optic lens, being the very last lens before the cd?
I did clean mine using a cotton swab dipped into 99% Isopropyl alcohol just enough to dampen the cotton swab and very gently run it across the lens and then flipped the swab around and just tapped it dry.
Is this an acceptable way to do this?
Roland
Hi Roland,
Yes, you did it the right way. I have seen people scrub the poor thing. Wrecks the suspension and sometimes can tear off the coil wires. That is pretty much the definition of a destroyed head. At least one tech used the wrong cleaner and ruined the lens. These are plastic, not glass. I guess maybe some might be glass, but you'd better assume each one is plastic.
The diffraction grating is a tedious thing to play with. You normally use a tool with a circular end and an off-center cylinder or pin. That pushes a slot back and forth, changing the position of the grating. For some players (if not all) there are three positions where you will see an E-F signal. Two don't work, the middle one does. The act of adjusting the grating can move the head around as well. If you are lucky, the player has an adjustment mode that turns off the sled motor. You need a focus lock and disc spin near the correct speed for this to have any hope of working. It is also a very touchy adjustment. Just in case you were thinking it could be fun to try.
Pioneer heads came from the factory with the diffraction grating way off. You are expected to align it. Real nice, Pioneer.
-Chris
Yes, you did it the right way. I have seen people scrub the poor thing. Wrecks the suspension and sometimes can tear off the coil wires. That is pretty much the definition of a destroyed head. At least one tech used the wrong cleaner and ruined the lens. These are plastic, not glass. I guess maybe some might be glass, but you'd better assume each one is plastic.
The diffraction grating is a tedious thing to play with. You normally use a tool with a circular end and an off-center cylinder or pin. That pushes a slot back and forth, changing the position of the grating. For some players (if not all) there are three positions where you will see an E-F signal. Two don't work, the middle one does. The act of adjusting the grating can move the head around as well. If you are lucky, the player has an adjustment mode that turns off the sled motor. You need a focus lock and disc spin near the correct speed for this to have any hope of working. It is also a very touchy adjustment. Just in case you were thinking it could be fun to try.
Pioneer heads came from the factory with the diffraction grating way off. You are expected to align it. Real nice, Pioneer.
-Chris
Still waiting for my Sony test disc to arrive.
It was supposedly mailed out on May 16th but not here yet.....
I'm looking forward to finishing my alignment checks.
It was supposedly mailed out on May 16th but not here yet.....
I'm looking forward to finishing my alignment checks.
Still waiting for my Sony YEDS-18 test disc to arrive from e-bay. It should have got here over a week ago but it was returned to the sender and had to be re shipped.
While I was waiting, I took the laser pickup out of my spare DP-1100 and installed my new pickup that I got from Kenwood 2 or 3 years ago to make sure it was working properly and take a power output reading with my laser meter to ensure it's within specs before I install it in my DP-3300 which will be recapped.
I was a little worried about attempting that but it was a piece of cake and the player played cd's with no problem!!
After that, I removed the new pickup and put away and re installed the old one.....everything still works!!
While I was waiting, I took the laser pickup out of my spare DP-1100 and installed my new pickup that I got from Kenwood 2 or 3 years ago to make sure it was working properly and take a power output reading with my laser meter to ensure it's within specs before I install it in my DP-3300 which will be recapped.
I was a little worried about attempting that but it was a piece of cake and the player played cd's with no problem!!
After that, I removed the new pickup and put away and re installed the old one.....everything still works!!
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