I have one of these really quite wonderful little machines. However it is suffering from this problem…
When the machine is switched on at the rear, then taken out of standby, drawer opened, CD loaded, drawer closed - it will read the CD index and all functions can be accessed successfully.
However, if the drawer is then opened and closed again the player displays OPEN when the drawer is closed and will not read the CD. If the player is then turned off at the rear and turned on again, it will function perfectly.
I have stripped the drive down, cleaned away old silicone lubricant, used tiny amounts of SPG on moving cogs and racks, replaced the door opening belt, contact cleaned the micro switch, and cleaned both sides of the laser lens. I have not, and see every reason not to, moved the potentiometer setting on the laser. Electronics have been left alone.
I’m guessing that on player power up, the laser head is positioned correctly to read the CD index, but fails to do so once the drawer open and close sequence happens, perhaps because the player doesn’t think the drawer is closed…
When the machine is switched on at the rear, then taken out of standby, drawer opened, CD loaded, drawer closed - it will read the CD index and all functions can be accessed successfully.
However, if the drawer is then opened and closed again the player displays OPEN when the drawer is closed and will not read the CD. If the player is then turned off at the rear and turned on again, it will function perfectly.
I have stripped the drive down, cleaned away old silicone lubricant, used tiny amounts of SPG on moving cogs and racks, replaced the door opening belt, contact cleaned the micro switch, and cleaned both sides of the laser lens. I have not, and see every reason not to, moved the potentiometer setting on the laser. Electronics have been left alone.
I’m guessing that on player power up, the laser head is positioned correctly to read the CD index, but fails to do so once the drawer open and close sequence happens, perhaps because the player doesn’t think the drawer is closed…
I'm not familiar with these players but if it does this consistently, I would expect an electronic problem rather than a mechanical.
Hugo
I've never worked on the Quads and can't even quickly see what type of mech it uses. Some later players used DVD drives.
I'm going to say it sounds like the loading cycle doesn't quite complete if the drawer appears closed but the display still shows open... but you need to prove that by looking at any inputs to the system control processor and seeing if they change as expected with drawer open and closed. There could two or three micro switches involved in all this.
I'm going to say it sounds like the loading cycle doesn't quite complete if the drawer appears closed but the display still shows open... but you need to prove that by looking at any inputs to the system control processor and seeing if they change as expected with drawer open and closed. There could two or three micro switches involved in all this.
The mechanism is labelled VAM2202A/B and it looks like images for a VAM2202 on the internet. It has a Quad specific controller board attached to the drive which has local voltage regulation, the power drivers for the motors and I assume the logic circuitry for the drive - a Philips set of chips. There are two micro switches, one for the laser sled and one for the drawer - I’ve cleaned both and checked electrical function. No sight of schematics anywhere…
Wouldn't the drawer need more than one microswitch? or perhaps an SPDT type if it is a single.
A single switch can only indicate two states, drawer open (or closed depending how its configured) and drawer not open or closed. It needs a second signal to confirm its reached the end of wherever its going.
A single switch can only indicate two states, drawer open (or closed depending how its configured) and drawer not open or closed. It needs a second signal to confirm its reached the end of wherever its going.
Yes I assumed that switches of some sort would be needed to tell the system when a) the drawer was fully out (and therefore turn the drawer motor off and presumably precondition the next drawer action to be a close) and b) tell the system when the drawer was closed. The microswitch for a) is a simple spring leaf single pole part that is pushed to make the circuit close by the drawer reaching the end of its open travel limit. I can't find anything (yet) to deliver the b) function. The mystery is that the system is able to receive some sort of signal to tell it that the door is 'closed' and that when it does all works well. However, as described this seems to break down once the system has received the signal from the a) function that the drawer is 'open'. So logically there is something about the receipt of this 'open' signal which seems to trigger the system into not being able to recognise that the drawer is 'closed' and therefore to initiate the LOAD sequence....
Hi! I don't know this cd player but, surfing on internet, it looks that this cd player is very prone to this fault but, I'd try two things:
There is one SMD capacitor, 1uf50V, check and replace if it suspect.
If capacitor is not the culprit, look for any Reset circuit and research the difference into power up wit rear switch, and reseting when the disc enter.
https://www.facebook.com/2374261996...reading-the-discs1st-photo-s/930968793656510/
There is one SMD capacitor, 1uf50V, check and replace if it suspect.
If capacitor is not the culprit, look for any Reset circuit and research the difference into power up wit rear switch, and reseting when the disc enter.
https://www.facebook.com/2374261996...reading-the-discs1st-photo-s/930968793656510/
Images attached show the drive mechanism, PCB attached to top of board which contains the BTL drivers for motors and (I assume) associated logic control, and ICs except the BTL. Two microswitches are identified - drawer switch has the brown and black wires attached and sled switch has orange and (different) black wires attached.
Attachments
I really don't know on this one. I was trying to think of a way one switch could work and there might be a way but it relies on the mech knowing the initial state and it never altering or getting confused.
If the drawer is open and the switch closed (lets say) and you then close the drawer the motor could run to close. How does it know when to stop? Could there be some mechanical thing on the tray to twang the switch again and signal closed?
The trouble with that is that it relies on the player always knowing which way to run the motor based on the last successful operation.
Without examining one I just can't say... the above is more a thought experiment as to whether its possible.
Maybe you could identify a Philips based player that uses the same mech and get some proper service info for the loader. There must be one, Quad wouldn't have a unique mech for a niche player, that's just not cost effective.
If the drawer is open and the switch closed (lets say) and you then close the drawer the motor could run to close. How does it know when to stop? Could there be some mechanical thing on the tray to twang the switch again and signal closed?
The trouble with that is that it relies on the player always knowing which way to run the motor based on the last successful operation.
Without examining one I just can't say... the above is more a thought experiment as to whether its possible.
Maybe you could identify a Philips based player that uses the same mech and get some proper service info for the loader. There must be one, Quad wouldn't have a unique mech for a niche player, that's just not cost effective.
It is a mystery. Have checked the operation of the microswitch for the tray. It definitely makes/closes when the tray is fully out. I also checked the resistance on this switch when the drawer was fully closed in case there was some sort of mechanism I couldn't see which closed the switch in this situation - it was open circuit when the drawer was closed. I have however followed your helpful thought on the service manual - the Marantz CD7300 uses the VAM2202 and has a detailed Service Manual on line. In this manual the tray microswitch is called a 'limit switch' which seems appropriate. Haven't yet found the sled(ge) microswitch but there are a lot of very small lines and writing on these diagrams
Good detective work
So, and just skimming it over very quickly... this looks to be the area for the tray. All those IC's seem to be some kind of H bridge driver for all the motors, pickup and so on. Puzzled why there is no R/C network shown across the motor output on pins 9 and 12. There is on all the others.
Random thought. Noisy (electrically noisy) motors can generate lots of spikes. Could that be glitching the chip in some way?
Pins 6 and 7 look to be the inputs.
More random thoughts... if its intermittent try a low value series resistor to the motor and a small non polarized cap across the motor.
Load switch... is that the sled do-dah or something else.
So, and just skimming it over very quickly... this looks to be the area for the tray. All those IC's seem to be some kind of H bridge driver for all the motors, pickup and so on. Puzzled why there is no R/C network shown across the motor output on pins 9 and 12. There is on all the others.
Random thought. Noisy (electrically noisy) motors can generate lots of spikes. Could that be glitching the chip in some way?
Pins 6 and 7 look to be the inputs.
More random thoughts... if its intermittent try a low value series resistor to the motor and a small non polarized cap across the motor.
Load switch... is that the sled do-dah or something else.