Troubleshooting CD Players

[classyharlan]

Pioneer PD-717

The lens, the glass part, had fallen out of the sled when I got the deck so I tried just dropping it back in. In this state the lens does go up and down on closing the tray.

Upon inserting a disc I hear the lens move once (the lens isn't visible with a disc in), immediately after that the disc starts to spin and I hear sound of the lens once more, then the disc starts to slow down eventually stopping without the TOC being read. From this state if I hit play it does the same lens movement/spinning.

If I repeatedly push play then, although the disc doesn't play, it will spin at normal speed, presumably because the spinning is activated by the lens movement and multiple play pushing means continues lens movement. (?)

After the player correctly senses the home postion, the focus search starts and the laser pickup lens moves up and down.

OK

If the disc spins, focus search was successful and the player achieved focus lock.

OK but it loses momentum quickly (once the lens movement stops)

The pickup may be good. If the table of contents is displayed but the player doesn't play, the pickup is either bad or the internal adjustments must be performed.

The TOC is not displayed and the player doesn't play.

If the player does focus search and the disc doesn't spin and you hear a sizzling sound, the disk motor is bad.

When the power is on, with a disc or without, if I put my ear right up to the deck I hear a constant hum, not a sizzle though.

 

[dr*audio]

The lens falling out is a common problem with Pioneer players. It has to be glued back in place. I have never had one to repair with this problem, so do a search and see what glue others have used. Normal Superglue clouds plastic so you have to use a non-outgassing cyanoacrylic glue meant for optical use.
I don't know if it matters if the lens is reversed.
Once you get the lens correctly mounted, if it still spins up and will not read the TOC, the laser is bad. These are no longer available.

Pioneer PD-717

The lens, the glass part, had fallen out of the sled when I got the deck so I tried just dropping it back in. In this state the lens does go up and down on closing the tray.

Upon inserting a disc I hear the lens move once (the lens isn't visible with a disc in), immediately after that the disc starts to spin and I hear sound of the lens once more, then the disc starts to slow down eventually stopping without the TOC being read. From this state if I hit play it does the same lens movement/spinning.

If I repeatedly push play then, although the disc doesn't play, it will spin at normal speed, presumably because the spinning is activated by the lens movement and multiple play pushing means continues lens movement. (?)



OK



OK but it loses momentum quickly (once the lens movement stops)



The TOC is not displayed and the player doesn't play.



When the power is on, with a disc or without, if I put my ear right up to the deck I hear a constant hum, not a sizzle though.

 

[classyharlan]

After fixing it in place with wood glue it works perfectly. Thank you as always for the advice.

 

[dr*audio]

After fixing it in place with wood glue it works perfectly. Thank you as always for the advice.

Wood glue was a good choice. Shouldn't outgas and makes a semi-permanent bond that can be easily removed if necessary, but should hold up well in normal use.

 

[classyharlan]

Kenwood DPC-761 (sorry this is a portable but the question is general I think)

I manually move out the sled and hit play with no disc and the player flat on the table. The sled moves to home then there is a constant motor sound but no lens movement. The motor sound doesn't stop until I cut the power.

Same as above but with the mecha tipped 90 degrees. The lens retracts and the sled moves to home then there is a motor sound and after a couple seconds the lens pops up and the motor sound stops.

Sled in the home position and pushing play with the player flat, the lens retracts but just slightly, then motor sound until cutting power.

Same as above but with the mecha tipped 90 degrees. The lens retracts, then motor sound until cutting power.

The motor sound is like air escaping from a balloon, I assume it's coming from the mecha.

 

[dr*audio]

The home switch isn't being closed. It sounds like something is broken in the sled drive. Could be a bad gear.

Kenwood DPC-761 (sorry this is a portable but the question is general I think)

I manually move out the sled and hit play with no disc and the player flat on the table. The sled moves to home then there is a constant motor sound but no lens movement. The motor sound doesn't stop until I cut the power.

Same as above but with the mecha tipped 90 degrees. The lens retracts and the sled moves to home then there is a motor sound and after a couple seconds the lens pops up and the motor sound stops.

Sled in the home position and pushing play with the player flat, the lens retracts but just slightly, then motor sound until cutting power.

Same as above but with the mecha tipped 90 degrees. The lens retracts, then motor sound until cutting power.

The motor sound is like air escaping from a balloon, I assume it's coming from the mecha.

 

[classyharlan]

In case this additional info changes anything:

Even if I manually turn the gear so the sled is as forward as it can go and the home switch plunger is undoubtedly pushed in, the behavior is the same.

My multimeter beeps on the home switch contacts when the plunger is pushed in (either manually or by the sled).

 

[dr*audio]

In case this additional info changes anything:

Even if I manually turn the gear so the sled is as forward as it can go and the home switch plunger is undoubtedly pushed in, the behavior is the same.

My multimeter beeps on the home switch contacts when the plunger is pushed in (either manually or by the sled).

So this does change things. Putting it in different positions changing the behavior plus this latest info indicates there could be a bad connection between the switch and the microprocessor. Maybe a crack in the pc board or broken wire from the switch or bad crimp on the connector.

 

[dbxdx5]

Working on a Bose Acoustic Wave CD-3000. When I insert a CD, it spins for a sec, then stops, not recognizing that there's a disc. I've tried tweaking the laser pot to give the diode a little more voltage. Not sure what's a reasonable range, resistance-wise, but I'm at 1500 ohms right now. In this YT vid, she's saying to aim for 1,000 to 1300 ohms. Input welcome.

 

[dr*audio]

Working on a Bose Acoustic Wave CD-3000. When I insert a CD, it spins for a sec, then stops, not recognizing that there's a disc. I've tried tweaking the laser pot to give the diode a little more voltage. Not sure what's a reasonable range, resistance-wise, but I'm at 1500 ohms right now. In this YT vid, she's saying to aim for 1,000 to 1300 ohms. Input welcome.

Is it doing focus search?

 

[dbxdx5]

Is it doing focus search?

I don't believe it is, though I'll have to verify tomorrow.

 

[RonDollah]

Hi Dr. Audio--

Picked up an early 90s JVC unit which turns on and plays all discs quite well for about 10 mins... then the power seems to just go out. Screen goes blank, music stops. Turn off and back on, and it works fine again for a few songs, then dies again.

Any thoughts on most likely culprits?

Thanks, A

 

[newzealand]

Hi Dr. Audio--

Picked up an early 90s JVC unit which turns on and plays all discs quite well for about 10 mins... then the power seems to just go out. Screen goes blank, music stops. Turn off and back on, and it works fine again for a few songs, then dies again.

Any thoughts on most likely culprits?

Thanks, A

i have a luxman player that does the same,

 

[dbxdx5]

I don't believe it is, though I'll have to verify tomorrow.

Meant to add that I tested both the sled and disk motor with my external power supply. They moved with as little as 1V applied. I also removed the clear cover from the home switch and cleaned the contacts with a strip of business card soaked in Deoxit D5. After cleaning I measured 0.3 ohms across the terminals (minus 0.2 ohms for my meter leads).

 

[dr*audio]

Hi Dr. Audio--

Picked up an early 90s JVC unit which turns on and plays all discs quite well for about 10 mins... then the power seems to just go out. Screen goes blank, music stops. Turn off and back on, and it works fine again for a few songs, then dies again.

Any thoughts on most likely culprits?

Thanks, A

Start measuring power supply voltages.

 

[classyharlan]

there could be a bad connection between the switch and the microprocessor. Maybe a crack in the pc board or broken wire from the switch or bad crimp on the connector.

Multimeter probe 1 on home switch node 1, I found a connector solder point on the sled for which it beeps when touching probe 2.

Multimeter probe 1 on home switch node 2, I found a connector solder point on the sled for which it beeps when touching probe 2 and depressing the switch plunger.

I am assuming perhaps incorrectly that continuity means the connection from home switch to laser via pc board is ok. I also checked continuity for intermediate steps: switch to board switch wire socket, wire socket to microprocessor, and wire socket to board connector socket.

 

[dr*audio]

Multimeter probe 1 on home switch node 1, I found a connector solder point on the sled for which it beeps when touching probe 2.

Multimeter probe 1 on home switch node 2, I found a connector solder point on the sled for which it beeps when touching probe 2 and depressing the switch plunger.

I am assuming perhaps incorrectly that continuity means the connection from home switch to laser via pc board is ok. I also checked continuity for intermediate steps: switch to board switch wire socket, wire socket to microprocessor, and wire socket to board connector socket.

Ok, so now see if it does focus search.

 

[classyharlan]

The behavior has changed slightly. Now when I manually move the sled out and then hit play with a disc in, after returning to home it does read no disc. When already in the home position it only starts making the motor sound. But I guess the reading no disc even with a disc in means the laser is bad.

 

[parman]

@dr*audio I've been looking at some old CD players and wonder what you think of a single drawer, carousel or cartridge as far as problems go. I like the single disc players but the ones I see are really old. Those are usally the ones Made in Japan.

 

[dr*audio]

@dr*audio I've been looking at some old CD players and wonder what you think of a single drawer, carousel or cartridge as far as problems go. I like the single disc players but the ones I see are really old. Those are usally the ones Made in Japan.

The single drawer players have far less to go wrong with them. Cartridge players are horribly unreliable, and tend to scratch the CDs or just deposit grease on them. People drop the cartridges and the detent balls fall out, allowing multiple CDs to be drawn into the player at the same time, jamming the player and ruining the CDs.
Of the 5 disc changers, Sonys are the most reliable.
Of the single disc players, Onkyo made the best built. I particularly like the DX-1800. It sounds great, stock, and the opamps can be upgraded for better sound.
On any used player you need to look for one that uses a Sony KSS-213 laser because replacements are readily available from BD Enterprises, the best source. Search on Google for CD Player laser cross reference.
KSS-240 and KSS-210A are also available from Liberty Electronics on E-bay. I have used their lasers and they are well made and last. Other sellers are selling cheap Chinese junk. Liberty found a good supplier in China for lasers.
Look for players made from 1989 on, with 8X oversampling.