Hi all
I am trying to sort a PS Audio Lambda Drive (CD transport). It was made for PS by Theta and is the same as their Data Basic (which I own as well).
These units use CDM9/60 (CDM9 pro iow). I have swapped optics on a few of these mechs from new CDM9/44 to sort them out. This unit is stumping me though.
When loading a disk the unit does its initial focus procedure and then starts spinning the disk to try and read TOC but 9 out of 10 times it fails and just end up speeding up and spinning for about 10 seconds or so until it gives up reading and gives an error on the display and goes blank or it just keeps spinning indefinitely. I t does seem to lock on the 8 cm CD icon.
The player has 3 “modules”. The loader has its own PCB which looks like it is Philips made with a TDA8808, JRC 4560 the TCA3702 or something I think. There is an unregulated PSU board (Theta) and then the main PCB (Theta) with the clock circuits and outputs, the SAA7310 another JRC 4560 near the CDM input and 037DPI as well as the TDA8809. The CDM and its loader PCB are now working as swapping this module into my working theta disks are read without a problem. I have also swapped the PSU boards and this made no difference. I am thus convinced the fault is on the main PCB…. But where to start? I have checked the 13 or so regulators on this board and they appear OK.
Any ideas anyone?
I am trying to sort a PS Audio Lambda Drive (CD transport). It was made for PS by Theta and is the same as their Data Basic (which I own as well).
These units use CDM9/60 (CDM9 pro iow). I have swapped optics on a few of these mechs from new CDM9/44 to sort them out. This unit is stumping me though.
When loading a disk the unit does its initial focus procedure and then starts spinning the disk to try and read TOC but 9 out of 10 times it fails and just end up speeding up and spinning for about 10 seconds or so until it gives up reading and gives an error on the display and goes blank or it just keeps spinning indefinitely. I t does seem to lock on the 8 cm CD icon.
The player has 3 “modules”. The loader has its own PCB which looks like it is Philips made with a TDA8808, JRC 4560 the TCA3702 or something I think. There is an unregulated PSU board (Theta) and then the main PCB (Theta) with the clock circuits and outputs, the SAA7310 another JRC 4560 near the CDM input and 037DPI as well as the TDA8809. The CDM and its loader PCB are now working as swapping this module into my working theta disks are read without a problem. I have also swapped the PSU boards and this made no difference. I am thus convinced the fault is on the main PCB…. But where to start? I have checked the 13 or so regulators on this board and they appear OK.
Any ideas anyone?
In my post above I forgot to mention that although it has read TOC a few imes, it never actually played the disc.
Could this be a fault with the SAA7310? I have fitted another TDA8809 already but this made no diff. The TDA8809 was salvaged from another scrap player so I am not + it was OK but there was no change in the behaviour of the player.
Would the player achieve its focus to try and read TOC if the 8809 is faulty?
Thanks all
Could this be a fault with the SAA7310? I have fitted another TDA8809 already but this made no diff. The TDA8809 was salvaged from another scrap player so I am not + it was OK but there was no change in the behaviour of the player.
Would the player achieve its focus to try and read TOC if the 8809 is faulty?
Thanks all
Hi tubenut,
Just poke around the first chip with a 'scope. The waveform is best viewed at 0.5uS / div and 0.5V / div. Expect around 1~1.5 Vp-p. There may be a filter with a couple small caps and a resistor near the chip.
By the first chip, I mean the chip that goes to the PU head flat connector. Not the coil drivers.
-Chris
Just poke around the first chip with a 'scope. The waveform is best viewed at 0.5uS / div and 0.5V / div. Expect around 1~1.5 Vp-p. There may be a filter with a couple small caps and a resistor near the chip.
By the first chip, I mean the chip that goes to the PU head flat connector. Not the coil drivers.
-Chris
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.