Troubleshooting CD Players
- Thread starter dr*audio
- Start date
dr*audio
Fish fingers and custard!
It's actually + / - 14V on this model; Vcc and Vee. I looked at the service manual and there are no IC protectors. You might still have a cap reversed, or you might have ruined the one you reversed and reinstalled it.
dr*audio
Fish fingers and custard!
Yes, also C912.
dr*audio
Fish fingers and custard!
Connect your black meter probe to the metal chassis, and then touch the red probe to:
Q901 pin 1, should read +14V.
Q902 pin 2 should read -14V.
Wrap tape around the red meter lead so that only the very tip is exposed. this will help prevent shorting things out when you slip with the probe.
Q901 pin 1, should read +14V.
Q902 pin 2 should read -14V.
Wrap tape around the red meter lead so that only the very tip is exposed. this will help prevent shorting things out when you slip with the probe.
j!m
Super Member
Recently resurrected a NAD 5300.
This was their top line (single disc) player from the "Monitor Series" in the 90's I guess it was. Not an easy model to find, so I took a chance on this "sort-of" working one.
Basically, it had a door that wouldn't open when I received it- that wasn't a problem when it left the seller, but it had to be fixed either way. I thought maybe the drawer switch was bad or dirty, because a KNOWN issue was that pushing the OPEN button was intermittent- it often took several presses to do anything.
After heavy use of colorful metaphors and removal of nearly every screw, I was able to get to the transport well enough to free to drawer. The cam was out of sync and just moving the tray to its limit manually fixed all that. Drive belt was intact and in good condition, so I left it. Drawer opens and closes smoothly now (when the button cooperated). Cleaned the plastic track for the drawer and lubricated with watch oil while I was there.
So, to the OPEN switch. The front panel button presses on a switch on a board behind the face plate. Okay; I'll just clean that switch out for a start... when I finally got to the switch, I found that the board holding the switch was not fully clipped into the retainer on the back of the face plate. Some (factory) glue was there, so since it was sold new, this switch was just a bit far away from the actuator (button). Clipped the board into proper location and that is also fixed.
Laser was clean but I cleaned the rails and lubed with watch oil while I was there. Working great!
Maybe these discoveries will assist someone in the future.
PS I DO still have an issue with this player, but it's minor in the grand scheme. The player has a remote, and every remote function works except for the variable output level. The player has fixed and variable outputs on the back (also digital out), and the variable is controlled by a motorized pot on the front. The motor for the pot is not running to turn the pot on remote command, or not getting the signal from the board or something...
Of course, it works fine if I turn the knob with my fingers, but maybe there is a known fix, or troubleshooting path to follow for that? As I said, it's minor, and does not impact function of the unit (I had to find another remote as it did not come with one), but I'd like to have this feature working if possible.
This was their top line (single disc) player from the "Monitor Series" in the 90's I guess it was. Not an easy model to find, so I took a chance on this "sort-of" working one.
Basically, it had a door that wouldn't open when I received it- that wasn't a problem when it left the seller, but it had to be fixed either way. I thought maybe the drawer switch was bad or dirty, because a KNOWN issue was that pushing the OPEN button was intermittent- it often took several presses to do anything.
After heavy use of colorful metaphors and removal of nearly every screw, I was able to get to the transport well enough to free to drawer. The cam was out of sync and just moving the tray to its limit manually fixed all that. Drive belt was intact and in good condition, so I left it. Drawer opens and closes smoothly now (when the button cooperated). Cleaned the plastic track for the drawer and lubricated with watch oil while I was there.
So, to the OPEN switch. The front panel button presses on a switch on a board behind the face plate. Okay; I'll just clean that switch out for a start... when I finally got to the switch, I found that the board holding the switch was not fully clipped into the retainer on the back of the face plate. Some (factory) glue was there, so since it was sold new, this switch was just a bit far away from the actuator (button). Clipped the board into proper location and that is also fixed.
Laser was clean but I cleaned the rails and lubed with watch oil while I was there. Working great!
Maybe these discoveries will assist someone in the future.
PS I DO still have an issue with this player, but it's minor in the grand scheme. The player has a remote, and every remote function works except for the variable output level. The player has fixed and variable outputs on the back (also digital out), and the variable is controlled by a motorized pot on the front. The motor for the pot is not running to turn the pot on remote command, or not getting the signal from the board or something...
Of course, it works fine if I turn the knob with my fingers, but maybe there is a known fix, or troubleshooting path to follow for that? As I said, it's minor, and does not impact function of the unit (I had to find another remote as it did not come with one), but I'd like to have this feature working if possible.
Last edited:
urbom
Member
Q901 13.5v
Q902 -13.9v through a dbt
dr*audio
Fish fingers and custard!
Put in a CD. Look at the voltage on P103 pin 2 with your meter, connecting the black lead to ground. You should see some voltage there, like 1V as it tries to advance the sled. If not, look at the voltage on R141, both ends. If that is 0V, you blew Q104. Game over.
urbom
Member
Sooo, when I can find r141, and it is 0v, can i pull q104 (48 pins!!) and put in a zif socket with a new ic?
dr*audio
Fish fingers and custard!
You can test at Q104 pin 20. I expected it to be a surface mount IC. If it's bad you could certainly use a 48 pin DIP socket. I would solder the new IC in. CEItron on e-bay has good parts like this. Also wehavethatitem. I wouldn't order from anyone else. Use the complete part number when searching: CXA1082BS.
urbom
Member
.15v on pin 2 of p103 and -4.96v at q104 pin 20. So much for easy
dr*audio
Fish fingers and custard!
No, it's easy, Q106 is blown. CEItron on ebay has it. He is a reliable seller.
STA341M "Original" Sanken 8P SIP IC 1 pc | eBay
(This is for 1) pc of the STA341M IC. Consolidated Electronics was created in February of 1979.
www.ebay.com
urbom
Member
I’m not worthy. I bow to your magnificance. I ordered the part you linked and hope it works and fixes this damn thing. If I had just put those caps in right the first time.No, it's easy, Q106 is blown. CEItron on ebay has it. He is a reliable seller.
STA341M "Original" Sanken 8P SIP IC 1 pc | eBay
(This is for 1) pc of the STA341M IC. Consolidated Electronics was created in February of 1979.www.ebay.com
dr*audio
Fish fingers and custard!
When you pull the board to replace Q106, check the continuity of the traces going from the +/-14V supplies to that IC, because it's possible one of them burnt and is open. That's about the only other thing it could be is a bad trace. +14 goes to pin 1, -14 goes to pin 5. Measure continuity back to the regulators where you checked the voltages.
urbom
Member
Continuity checked and all good. I really cannot express how grateful I am that you somehow put up with my stupidity. The Q106 should be here thursday.
Kevin
dr*audio
Fish fingers and custard!
You really should get that type of thing from Digikey. LM4562 is what you want to use.