Xenon-Codex
Active Member
The center area around the plate. It was missing a screw and one nipple next to the screw is broken.
Laserology - CD Players and why they stop reading
- Thread starter Rob.
- Start date
Xenon-Codex
Active Member
The white plate is very picky to be inserted correctly, one corner was 0,5mm off. It's now in place and the player works.
Xenon-Codex
Active Member
Bought two CDM4/19, need to get the "platter" thing for the other. I have one which is totally dead.
Still the player skips after 1/4 of the disc. The counterplate seems to be okay, I also pressed it by finger but no help.
Still the player skips after 1/4 of the disc. The counterplate seems to be okay, I also pressed it by finger but no help.
Xenon-Codex
Active Member
I have yet another player (Technics SL-PG200A), it starts to play but stops after a couple of minutes, and the head knocks loudly against the base. With the original unit it worked, even with the blue cap which was out of spec.
Xenon-Codex
Active Member
This germany-sourced Technics started to work after changing the blue cap, and the lens needed cleaning. 20 minutes to repair. Only thing is loud whining sound from the laser unit with certain CD-R's, beginning and the end are silent.
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Xenon-Codex
Active Member
Saved this unit (again) from the dump. It had cut power cord, but is working. Only problem is that with CD-R's it seems to have difficulties as track changes take even 2-3 seconds, and it sounds like it looses focus or something. It plays fine to the end of the disc.
13mh13
Active Member
Going back to Lampy's orig. Laserology article, one particular image might be relevant to the issues with my Kwd dp-47 laser issue:
The Sony heads were not sealed (unlike Philips, which were). But I'm not sure how big of an issue this might be. My KSS-152 looks clean, and the Kenwood dp-47 was very clean inside and out when I acquired it.
So, while the Q-tip maintenance might make for impressive photography, I'm not sure how REALLY useful these, ahem, tips by Lampy REALLY are. And certainly, all the surgery with delicate coil wire is cringey AF. Yikes, Lamps!
The Sony heads were not sealed (unlike Philips, which were). But I'm not sure how big of an issue this might be. My KSS-152 looks clean, and the Kenwood dp-47 was very clean inside and out when I acquired it.
So, while the Q-tip maintenance might make for impressive photography, I'm not sure how REALLY useful these, ahem, tips by Lampy REALLY are. And certainly, all the surgery with delicate coil wire is cringey AF. Yikes, Lamps!
dr*audio
Fish fingers and custard!
The problem is not dirt if you can watch the rf signal on an oscilloscope and it drops off as the CD plays. It's the laser. Cleaning is rarely the issue.Going back to Lampy's orig. Laserology article, one particular image might be relevant to the issues with my Kwd dp-47 laser issue:
The Sony heads were not sealed (unlike Philips, which were). But I'm not sure how big of an issue this might be. My KSS-152 looks clean, and the Kenwood dp-47 was very clean inside and out when I acquired it.
So, while the Q-tip maintenance might make for impressive photography, I'm not sure how REALLY useful these, ahem, tips by Lampy REALLY are. And certainly, all the surgery with delicate coil wire is cringey AF. Yikes, Lamps!
13mh13
Active Member
When a CD is inserted and it spins up, I see a rough EFM pattern on the 'scope briefly .... but within a second or two, the CD spins down to a stop as the EFM vanishes. So the DP47 never gets to the TOC.
I can see the typical red dot (using my iPhone camera for safe close-up viewing); the brightness is similar to another working DP47.
I am wondering if I can't solder some additional power leads to that laser? Maybe right at joints where the pwr pot is soldered? Even a 1.5v AAA batt?
dr*audio
Fish fingers and custard!
What is the peak to peak amplitude of the eye pattern?
Quadman2
Lunatic Member
About to do a tear-down on a SONY CX-300 CD player (2 belt change), and the one thing that was stressed in my look-see online was do NOT touch/brush against the laser head! Pay special attention whenever near this component.! This might have been mentioned in the shared "docu", but I didn't read it mentioned/highlighted. Might have been mentioned, but missed it, and thought to reinforce this aspect when dealing with the innards, and their "delicacy".
Q
Q
dr*audio
Fish fingers and custard!
This is probably mostly concerned with static discharge or getting shmutz on the lens. They are not fragile to being touched.
Quadman2
Lunatic Member
Sorry wasn't clear. Was meaning a small attach frame that might put the laser out of alignment if moved so slightly.
Q
13mh13
Active Member
Yikes -- apologies -- I was measuring EFM (and not RF).
Indeed, some initial EFM activity on the troublesome dp47 (see photo), but that zeros out -- ahem, flatlines -- once the troublesome dp47 gives up on the TOC, and spins down.
On my normal/functional dp47, good RF eye pattern (see photos).
If anyone wants to send me a free KSS-123 to play with, please PM me!
ABOVE: Good dp47. 'Scope on RF pin on daughter board. The EFM pin is on main board.
Above: 'Scope probes on EFM and GND service pins, main board.
ABOVE: EFM on bad dp47 as it spins up and attempts at reading TOC, but then quits, and spins down.
Above: Good dp47.
Above: 'Scope probes on EFM and GND service pins, main board.
Above: Good dp47.
ABOVE: Proof of ownership of both units. This is very important folks. Too often, forum discussions are just lazy text-talk. Just low-effort conversation. Not many want to SHOW THEIR WORK. PUT THEIR MONEY WHERE THEIR MOUTH IS.
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///MTechnics
New Member
I want to learn this alchemy/wizardry you all talk about...!
Have a small stack that all skip. Going to try and find a local repair shop.
Have a small stack that all skip. Going to try and find a local repair shop.
Xenon-Codex
Active Member
I saved this Sony from the dump. It plays all cd's flawlessly, but especially with CD-R's is seems to have difficulties to read the disc, but it always reads after hard seeking, and then plays. Is there anything to do? CDP-XE220 is the same thing as this 230. KSS-213 mechanism.
Xenon-Codex
Active Member
How many has Philips CDM 4/20? It was used in the CDC-series changer systems, but the platter is different. Started to work in Technics SL-PG200A after changing the laser to the original base.
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