I acquired up a Nakamichi CDC-3A CD player recently as it was included in the purchase of a Nakamichi TA-2A receiver. It has two issues (unrelated): it hangs somewhere about 8 to 10 min into a disc, and the sound quality delivered through the RCA jacks is poor.
The hang issue is a stutter and/or a stop at 8-10 min in, typically accompanied by a slight jump backwards on the timer or a stopped timer. If I fast-forward through this by 45 sec or so, play can resume. There are sometimes other stutters/stops outside of the 8-10 min range, but often the player continues to play to the end of the disc without incident. I have not had this problem appear at all during play of the last half of a disc.
Figuring this is a tracking issue, especially because of the slight backup of the laser when the problem hits, I have pulled the laser assembly off (it is a top-mounted, downward-firing unit of the Pioneer family) and rubbed down the rail the laser assembly slides on with a soft cloth. I have done this with the laser parked at both the start and end position so I might get the whole rail, and repeated it twice, but this has not fixed the issue. I might try it once again, with some solvent on the cloth.
I am open to suggestions of the next things to try. From reading around, it seems one possibility is to up the tracking gain. I haven’t located a service manual for this player, but I see 7 pots on the PCB, shown below. VR101-VR106 are the ones with amber tops in the middle of the view; VR107 is the one with the blue top (lower right). If someone has the SM on this player or otherwise knows, I’d be grateful to hear which one is tracking gain adjustment.
It is also possible that there is a problem elsewhere in the circuit that has caused the tracking gain to decrease (failing cap, giving poor voltage for ICs?), but without a schematic it is hard to know where to test for voltages, etc. The caps do not have appearance defects (except for the glue) and the board does not have other problems, like heat marks.
The other problem (poor sound quality via the RCA jacks, similar to a tinny radio) isn’t much of a concern presently as I am playing via digital-out to an Adcom GDA-700, but if I can get my hands on a schematic I would like to go after this it as some point.
Thanks for any assistance.
The hang issue is a stutter and/or a stop at 8-10 min in, typically accompanied by a slight jump backwards on the timer or a stopped timer. If I fast-forward through this by 45 sec or so, play can resume. There are sometimes other stutters/stops outside of the 8-10 min range, but often the player continues to play to the end of the disc without incident. I have not had this problem appear at all during play of the last half of a disc.
Figuring this is a tracking issue, especially because of the slight backup of the laser when the problem hits, I have pulled the laser assembly off (it is a top-mounted, downward-firing unit of the Pioneer family) and rubbed down the rail the laser assembly slides on with a soft cloth. I have done this with the laser parked at both the start and end position so I might get the whole rail, and repeated it twice, but this has not fixed the issue. I might try it once again, with some solvent on the cloth.
I am open to suggestions of the next things to try. From reading around, it seems one possibility is to up the tracking gain. I haven’t located a service manual for this player, but I see 7 pots on the PCB, shown below. VR101-VR106 are the ones with amber tops in the middle of the view; VR107 is the one with the blue top (lower right). If someone has the SM on this player or otherwise knows, I’d be grateful to hear which one is tracking gain adjustment.
It is also possible that there is a problem elsewhere in the circuit that has caused the tracking gain to decrease (failing cap, giving poor voltage for ICs?), but without a schematic it is hard to know where to test for voltages, etc. The caps do not have appearance defects (except for the glue) and the board does not have other problems, like heat marks.
The other problem (poor sound quality via the RCA jacks, similar to a tinny radio) isn’t much of a concern presently as I am playing via digital-out to an Adcom GDA-700, but if I can get my hands on a schematic I would like to go after this it as some point.
Thanks for any assistance.
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