Hello everybody,
This is my first post here, but I keep reading your interesting and helping discussions.
I am having some troubles with my meridian 508.20 as it skips when the reproduction of the CD is at the middle (or at the end). The player has no problems at reading the CDs and CDRs (so I assume the laser is OK), it just skips when it reaches the middle of the CD.
I have read that this could be due to some grease that is sticking in the mechanism so I opened up the player and pull out the transport to clean it.
To be honest I did not find much to clean and the grease that I found on the gears did not look like it was hardened, but I might have not reached the right point to clean. Anyway the player continues to skip inspite of the little cleaning that I did.
What else do you think I could do?
Thank you
Fabrizio
This is my first post here, but I keep reading your interesting and helping discussions.
I am having some troubles with my meridian 508.20 as it skips when the reproduction of the CD is at the middle (or at the end). The player has no problems at reading the CDs and CDRs (so I assume the laser is OK), it just skips when it reaches the middle of the CD.
I have read that this could be due to some grease that is sticking in the mechanism so I opened up the player and pull out the transport to clean it.
To be honest I did not find much to clean and the grease that I found on the gears did not look like it was hardened, but I might have not reached the right point to clean. Anyway the player continues to skip inspite of the little cleaning that I did.
What else do you think I could do?
Thank you
Fabrizio
this is a picture a took of the transport
from another thread I read this shoupd be a Philips CDM 12.4
what is your thought?
thank you
from another thread I read this shoupd be a Philips CDM 12.4
what is your thought?
thank you
An externally hosted image should be here but it was not working when we last tested it.
That is a CDM12.4
You need to turn the black worm gear by hand to move the pickup clear of the blue nylon gear.
Then remove the blue gear... it's a push fit with clips at the top, just be careful removing it. Wash the gear in alcohol etc and use paper/card to remove all grease from the teeth of the gear, also on the inner teeth. The original problem is the grease solidifying and getting hard "grains" in it that jam the gears.
Now examine the gear... they are very soft. Are there any burrs ? If there are and they catch then you have a problem.
Clean the worm gear in the same way.
The pickup should be "free" to move along it's track. Look at ALL the friction points on the pickup. Apply a tiny dab of grease here. Apply a dab to the metal rail. Make sure there is no hard grease in the gear "rack" on the pickup.
Use a plastics compatable grease to reassemble... this is critical and the viscosity is important. I always used this,
ELECTROLUBE|SPG35SL|SPECIAL PLASTICS GREASE, 35ML | CPC
Apply a light smear to the teeth of the gears.
That hopefully should resolve any playability issues.
You need to turn the black worm gear by hand to move the pickup clear of the blue nylon gear.
Then remove the blue gear... it's a push fit with clips at the top, just be careful removing it. Wash the gear in alcohol etc and use paper/card to remove all grease from the teeth of the gear, also on the inner teeth. The original problem is the grease solidifying and getting hard "grains" in it that jam the gears.
Now examine the gear... they are very soft. Are there any burrs ? If there are and they catch then you have a problem.
Clean the worm gear in the same way.
The pickup should be "free" to move along it's track. Look at ALL the friction points on the pickup. Apply a tiny dab of grease here. Apply a dab to the metal rail. Make sure there is no hard grease in the gear "rack" on the pickup.
Use a plastics compatable grease to reassemble... this is critical and the viscosity is important. I always used this,
ELECTROLUBE|SPG35SL|SPECIAL PLASTICS GREASE, 35ML | CPC
Apply a light smear to the teeth of the gears.
That hopefully should resolve any playability issues.
Hello Mooly thank you for your kind reply.
I have already checked and cleaned the blue and the black gears (using a needle), but I did it turning the black worm gear to see and clean all teeth (apart from those on the other side othe the blue gear). I wanted to remove the gears but did not know how to do it, I could not just pull the blue gear out.
why you say the gear is soft?
Difficult to judge the friction points where pickup slides. Turning the black gear by hand all seems to move freely but the little motor might not find it so easy.
Do you know if there is a way to tune the tracking? This could be another reason for the skipping issue..
Thanks.
I have already checked and cleaned the blue and the black gears (using a needle), but I did it turning the black worm gear to see and clean all teeth (apart from those on the other side othe the blue gear). I wanted to remove the gears but did not know how to do it, I could not just pull the blue gear out.
why you say the gear is soft?
Difficult to judge the friction points where pickup slides. Turning the black gear by hand all seems to move freely but the little motor might not find it so easy.
Do you know if there is a way to tune the tracking? This could be another reason for the skipping issue..
Thanks.
The blue gear has integral "clips" molded into it. Just very gently prise them and the gear pulls straight off. The blue gear is often of a plyable soft nylon material rather than a hard plastic. You have to clean/check the teeth underneath that engage with the rack on the pickup.
The motor is held by a single metal clip. It's released from the top and just pushes back in to refit.
Friction points are where the pickup slides. In your photo its at the very top. The pickup slides along the plastic of the chassis. Look at both sides, top and bottom.
An old AVO8 meter on ohms x1 range put across the sled motor is sufficient to move the pickup slowly from end to end. I've never had a sled motor fail on these.
The motor is held by a single metal clip. It's released from the top and just pushes back in to refit.
Friction points are where the pickup slides. In your photo its at the very top. The pickup slides along the plastic of the chassis. Look at both sides, top and bottom.
An old AVO8 meter on ohms x1 range put across the sled motor is sufficient to move the pickup slowly from end to end. I've never had a sled motor fail on these.
I have seen the "integral clips" into the blue gear but It didn't seem so easy to press them all together to release the gear, I will have a better look. But my feeling is that the stucking grease, if any, is not there.
Also, the blue gear is hard.
I don't know if this can be of any help but the player usually skips when is at the middle of a CD (not at the beginning or at the end) and it always jumps back of few seconds and after the first time it has jumped it usually continues playing normally.
It sounds like a mechanical problem, but could it also be misalignment?
I also find this fine tuning of the player, I will try it, you never know..
http://www.hifi-advice.com/meridian-config-menu-info.html
Ciao
Also, the blue gear is hard.
I don't know if this can be of any help but the player usually skips when is at the middle of a CD (not at the beginning or at the end) and it always jumps back of few seconds and after the first time it has jumped it usually continues playing normally.
It sounds like a mechanical problem, but could it also be misalignment?
I also find this fine tuning of the player, I will try it, you never know..
http://www.hifi-advice.com/meridian-config-menu-info.html
Ciao
I tried that fine tuning but unfortunatelly didn't help.
So here again with the transport out.
Having a better look at the blue gear (and yes it is quite soft plastic) I think I should try to clean it better. But really I cannot see how to safelly take it out from that pivot. I even tried to bend those little clips with a little screw driver but I don't think this is the proper way.
So here again with the transport out.
Having a better look at the blue gear (and yes it is quite soft plastic) I think I should try to clean it better. But really I cannot see how to safelly take it out from that pivot. I even tried to bend those little clips with a little screw driver but I don't think this is the proper way.
An externally hosted image should be here but it was not working when we last tested it.
Bending those clips is the proper way
It will come off easily... I have worked on many many of these.
OK I will try again very patiently ..
to remove the blue gear, I use a screw driver in the version as showed about
Schraubendreher abgewinkelt, für Schlitzschrauben : Bahco-Werkzeuge
What is the english name for this tool? My english is bad. but I think, the name is "angled screwdriver" or "bend screwdriver".
go to post #34 about
bigsby on a tele with vintage bridge - Telecaster Guitar Forum
The bend must be in the correct kind appropriate for this task.
An additional advice: look to a used computer cd drive CDD3610 - except the laser head all parts (like the blue gear and the fixing stuff for the guide rods so as the sleed motor) are the same.
Schraubendreher abgewinkelt, für Schlitzschrauben : Bahco-Werkzeuge
What is the english name for this tool? My english is bad. but I think, the name is "angled screwdriver" or "bend screwdriver".
go to post #34 about
bigsby on a tele with vintage bridge - Telecaster Guitar Forum
The bend must be in the correct kind appropriate for this task.
An additional advice: look to a used computer cd drive CDD3610 - except the laser head all parts (like the blue gear and the fixing stuff for the guide rods so as the sleed motor) are the same.
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Oh I finally did it!
very carefully and little by little I bent one and then another of the three little climps and the blue gear came out very easely!!
As I suspecter it was not particulary dirty.
What I did find dirty is where the transport slides on the plastic (upper part of my picture). I could not see anythink by eye, but using a little sheet of paper I could find a lot of that brown decomposed nasty grease that was hidden under the plastic.
After cleaning I put every thing back in their place.. and.. guys I know I shouldn't be talking too soon, but the player seems to be working correctly without skiping!!!!!)))
Can't believe it!
Let's hope it's really fixed.. ;-)
very carefully and little by little I bent one and then another of the three little climps and the blue gear came out very easely!!
As I suspecter it was not particulary dirty.
What I did find dirty is where the transport slides on the plastic (upper part of my picture). I could not see anythink by eye, but using a little sheet of paper I could find a lot of that brown decomposed nasty grease that was hidden under the plastic.
After cleaning I put every thing back in their place.. and.. guys I know I shouldn't be talking too soon, but the player seems to be working correctly without skiping!!!!!
)))Can't believe it!
Let's hope it's really fixed.. ;-)
Pleased to hear it's working. That grease was a major problem at the time.
Just be aware that you can not swap the blue gear for the "white" one used on similar mechs. Although they appear similar the "backlash" is different and the CDM12.4 fails to read the TOC when these gears are used.
Also the grey platter is different to the black ones (magnetic polarity of clamp is reversed)
Just be aware that you can not swap the blue gear for the "white" one used on similar mechs. Although they appear similar the "backlash" is different and the CDM12.4 fails to read the TOC when these gears are used.
Also the grey platter is different to the black ones (magnetic polarity of clamp is reversed)
In my own CDD3610 devices follow mechanical parts from the loader are different:
1) the clamper unit (outline and magnetic polarity of clamp itself is reversed, as you say)
2) the optical pickup
3) the motorpulley
The gear color is also blue, only the (very little) fixing parts for the guide bar (guide rail) are here in black (at CDM12.4 mech this color is white).
But it is not to rule out, that there are different mech. versions of CDD3610.
But still good for a first task to disassembly to get practice.
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It shouldn't be too thick or "sticky" if you apply it to the worm gear. If it is it can cause problems reading the disc contents as the CDM12.4 scans the whole disc at very high speed when it reads the TOC. If the grease is thick it slows that down and it can throw it out as an error. It's not that critical, just nothing too thick or goey.
I would just try it on the sliding parts to begin with.
I would just try it on the sliding parts to begin with.
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