CED VideoDisc and Player Discussion

[robertsradios]

Hi again from the UK. Problems from the start. First it wouldn't drop the tray. There was a whirring sound coming from the motor that drops the tray. The belt seems to be loose. Touch belt which starts cam and tray drops but motor keeps turning. Touch motor pulley to stall motor and disc motor starts and the needle carrier repositions. Does this mean that the belt from the tray motor needs to be replaced? Presumably, the electronics rely on the motor stalling to know whether or not the tray has dropped. Is this correct?
In this condition (tray dropped, disc spinning, needle positioned) if I press RESET the needle carrier moves back and when it reaches the rest position the motor controlling it keeps whirring away. So how do the electronics know the needle carrier is the rest position? Is there a microswitch? Does it rely on a stalled motor like the tray motor? If so does it need a new belt?
When the main board was tried in a working machine there was no Red in the Video or RF outputs. Anyone know of a simple reason this might be so? Many questions I know but hopefully someone will be able to provide answers.
Regards robertsradios

[brother]

Hi
You have picked up on the general operation of the unit - the complete operation is based on various microswitches located at the rear of the machine and one on the laod tray near the front so it knows disc is in place before tray drops.

I am still no expert and I have not identified what switch tells the need arm to start - it returns mechanically on the same principal of a record player (it reached a limiter to return to its resting postion).

There is no doubt that the belts are the cause of the failure of operation these can be pruchased cheeply from the CED Magic site.

The colour issue is out of my league but Tom (CED Admin) will view these topic so be a bit patient and he will reply.

On the basis that the problem with you manchine is the belt set up dont worry too much about the main board being tested in a another machine this may be a compatability issue and a bit of a red herring in getting you machine up and running.

Kind Regards
_________________
All the girls love me like a brother

[robertsradios]

Hi, after a bit of fiddling I found out the following. When you put a disc in the tray motor lowers the disc tray. When it hits the end stop it stalls, the stall current tells the electronics to go start the disc motor and start moving the needle arm. Mounted on top of the arm is a long thin piece of metal at rightangles to the arm. This fits into a censor when the main board is in the down position. In this piece of metal there is ahole in a position that corresponds to the end of the disc. I think the sensor is actually 2 sensors. 1/ an optical sensor to detect the end of the disc using the hole. 2/ a magnetic sensor to detect when the arm is in the rest position. After the tray motor tells the arm to start it positions the needle over the start of the disc and searches a bit to detect the start of the side. It then syncs to the signals and proceeds to read from the disc. When it detects the end of the disc (or you press reset) the arm moves back. When it reaches the rest position the sensor tells the arm motor to stop and starts the tray motor to lift the tray. When the tray reaches the top of it's travel it stalls. The electronics detect the stall current and switches off. If this is actually the way it works its a bit nifty. A loose tray belt will prevent the tray motor from stalling and so the arm won't move to play the disc.
Anyone got a source for 23m - 24mm belts in the UK?

[brother]

This is good info - it appears you have invested a great deal of time is confirming operation.

This does ring true with one of my Hitachi players which goes a bit out of sync tray trys to lift when playing or other weird combinations due to motor sticking.

Dont waiste your time hunting for Belts in UK - by them from CED magic for pence approx $1 postage. I have ordered two lots and are here withinin the week - you can access the parts list through the main site. If you got a Paypal account its just a few clicks of button -no wainting in line at the post office to convert your pounds.

Last order I placed with CED Magic was £5.98 delivered - absolute peanuts.

Kind Regards
_________________
All the girls love me like a brother