On Jul 25, 12:05 pm, "Arny Krueger" <ar...@hotpop.com> wrote:
> Why bother fixing it?
I got it for free; it seems like a (fairly) nice CD player; just curious about the sound.
I really don't know if I actually need the schematic. I'm pretty sure it's a bad op-amp. The CD spindle motor won't activate, even though the motor tests fine and so do the transistors responsible for supplying the motor voltage.
It's just something to tinker with on a rainy afternoon, that's all......
I got it for free; it seems like a (fairly) nice CD player; just curious about the sound.
I really don't know if I actually need the schematic. I'm pretty sure it's a bad op-amp. The CD spindle motor won't activate, even though the motor tests fine and so do the transistors responsible for supplying the motor voltage.
It's just something to tinker with on a rainy afternoon, that's all......
The fault you describe really is a bit "my car won't start even though there's fuel in the tank. The engine cranks so the battery is fine. I suspect it might be a bad radiator ... "
Sorry to put it that way, but very few problems with discs failing to spin up, are ever anything to do with the motor's drive electronics, *unless* the motor was faulty in the first place, in which case, occasionally, the motor driver IC, where one is used, will be damaged. Where the drive is from a four transistor bridge, it's very rare for them to have failed, bad motor or not. The disc failing to spin up, when it's definitely *not* a motor problem, is almost invariably because the system control is not releasing the motor servo into a 'run' condition.
First checks should be :- If you move the laser down its track manually, then open and close the drawer, does it then home ? Does the laser burn ? Does it attempt focus ? With a disc in, does it achieve focus ? Does it attempt to rotate the disc at all ? Are any pots in it way off centre (if you don't know its pedigree, the phantom pot-twiddler may have been in there before you ... ) d;~}
Collect a bit more info, then let us know, and we'll see if we can suggest some more things you can look for.
All I know at this stage is that the CD will not spin under any condition...HOWEVER, when you turn the power off, the CD will spin maybe a quarter of a turn while the unit is powering down.
And here's a strange fact: The other day I started messing with the player after having it sit for a couple of weeks. I switched it on and inserted a disc. Quite unexpectedly, it spun the disc and the disc's track information appeared in the digital readout window!
At that point I should have pressed "play" to see what would happen, but I ejected the disc and re-inserted it. Back to square one--the disc didn't move.
This has been the one and only time the player has ever spun a disc since I acquired it.
I have measured the voltage coming off of the four-transistor bridge. Whenever a disc is inserted, the necessary 5 volts appears for a MICRO- second, and then the voltage goes back to zero.
> All I know at this stage is that the CD will not spin under any > condition...HOWEVER, when you turn the power off, the CD will spin > maybe a quarter of a turn while the unit is powering down.
> And here's a strange fact: The other day I started messing with the > player after having it sit for a couple of weeks. I switched it on > and inserted a disc. Quite unexpectedly, it spun the disc and the > disc's track information appeared in the digital readout window!
> At that point I should have pressed "play" to see what would happen, > but I ejected the disc and re-inserted it. Back to square one--the > disc didn't move.
> This has been the one and only time the player has ever spun a disc > since I acquired it.
> I have measured the voltage coming off of the four-transistor bridge. > Whenever a disc is inserted, the necessary 5 volts appears for a MICRO- > second, and then the voltage goes back to zero.
Respectfully, you emailed me first about this player. I assumed you had actualy looked in the CD repair FAQ. Apparently, that wasn't the case. Instead of taking up everyone's time answering basic questions, please go to the "startup problems" sections there and attempt to determine exactly what it is or is not doing. Then, everyone can be of more help.
As has been noted by others, the spindle motor failing to spin is almost never a problem with the motor or its immediate driving electronics, but rather with the optical pickup not getting focus lock due to any number of causes. With your erratic behavior it could even be a something mundane like a bad flex cable. And, it could still be a dirty lens.
Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.
On Jul 26, 7:06 pm, Sam Goldwasser <s...@minus.seas.upenn.edu> wrote:
> Respectfully, you emailed me first about this player. I assumed you > had actualy looked in the CD repair FAQ. Apparently, that wasn't the case.
Hi, Sam:
I really apologize, but I don't think I e-mailed you about this player. Unless I am having a severe case of amnesia, my original post here is the first time I have discussed this player online. I did have a question about a Yamaha player a couple of months ago, but that issue has been resolved.
If I did indeed e-mail you about this player, please accept my apologies. I will consult the CD repair FAQ as you have directed.
EADGBE <hwbossh...@comcast.net> writes: > On Jul 26, 7:06 pm, Sam Goldwasser <s...@minus.seas.upenn.edu> wrote:
> > Respectfully, you emailed me first about this player. I assumed you > > had actualy looked in the CD repair FAQ. Apparently, that wasn't the case.
> Hi, Sam:
> I really apologize, but I don't think I e-mailed you about this > player. Unless I am having a severe case of amnesia, my original post > here is the first time I have discussed this player online. I did > have a question about a Yamaha player a couple of months ago, but that > issue has been resolved.
> If I did indeed e-mail you about this player, please accept my > apologies. I will consult the CD repair FAQ as you have directed.
My apologies. It was someone else. Probably the "long shot" part made me think it was you. :)
Anyhow, do read the CD repair FAQ and then you can post your findings.
Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.
I have looked at the CD repair FAQ (very informative!), and I have done the following:
1. I have cleaned the lens with isopropyl alcohol.
2. I have discovered that the laser pickup WILL NOT re-center itself under any condition if I manually move it away from the motor spindle.
3. As far as I can tell by simple observation, the laser pickup DOES NOT light up under any condition. (I looked at the lens from an oblique angle about 6 inches away from it in a darkened room.)
4. I have verified that the lens drive motor AND the CD spindle motor do work OK. (I unplugged each motor's wiring harness and applied a small DC voltage.)
5. I have cleaned the contacts on the little leaf switch that opens and closes whenever the CD drawer opens and closes and verified that the switch is opening and closing normally.
6. I have verified that all wiring harness connectors are clean and well-seated.
Somehow, this player simply will not turn the CD playing circuits on when the drawer closes. I think the logic IC is fried. Oh well, I needed a few electronic parts, so now I have a whole box full!
EADGBE <hwbossh...@comcast.net> writes: > I have looked at the CD repair FAQ (very informative!), and I have > done the following:
> 1. I have cleaned the lens with isopropyl alcohol.
> 2. I have discovered that the laser pickup WILL NOT re-center itself > under any condition if I manually move it away from the motor spindle.
This may be the main problem. This is usually done regardless of the state of the laser pickup. So, either the sensor isn't working or there is a problem with the motor driver.
> 3. As far as I can tell by simple observation, the laser pickup DOES > NOT light up under any condition. (I looked at the lens from an > oblique angle about 6 inches away from it in a darkened room.)
So, not even a tiny red dot?
Did you reset the sled to the center? It might not light up if the sensor thinks it's starting at the wrong place.
Else, there is a problem with turning on the laser. You did say it recognized the ToC once, right? So the laser itself works.
Could be a bad connection/bad cable.
> 4. I have verified that the lens drive motor AND the CD spindle motor > do work OK. (I unplugged each motor's wiring harness and applied a > small DC voltage.)
> 5. I have cleaned the contacts on the little leaf switch that opens > and closes whenever the CD drawer opens and closes and verified that > the switch is opening and closing normally.
> 6. I have verified that all wiring harness connectors are clean and > well-seated.
> Somehow, this player simply will not turn the CD playing circuits on > when the drawer closes. I think the logic IC is fried. Oh well, I > needed a few electronic parts, so now I have a whole box full!
Doubt it. :) Certainly possible, but the most complex most expensive part really isn't likely to be bad.
Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.
