Onix CD-1----Play, no tray

[jbeckva]

Just a jump the gun theory at the moment, but let's say it works like this..

1. Button pressed
2. Controller IC "allows" TDA to swing into action, driving the motor

BUT

3. Controller IC is also just a split second layer EXPECTING the limit switch to change states i.e. either the drawer has started traveling to "closed" or "open", depending on it's previous state.

AND

4. Either the delay isn't long enough anymore.. Controller IC says "well.. I don't see it opening or closing", so I give up

OR

5. The voltage differential being presented to the motor is NOT enough anymore, therefore the TDA needs replaced.

Soo.. perhaps there may be an outboard cap around the controller IC that through typical RC action is in charge of this delay... and is shorted..

or

TDA chip bad

or

Controller IC bad

 

[laatsch55]

Let me see what 9-12 is

 

[jbeckva]

I think you are getting close to putting a resistor on the output instead of the motor as a load to test this.

I'd just like to see if Lee sees anything close to 5V being presented to the motor i.e. between the two output pins. Gotta watch both of them at the same time to determine if it's a measly 2.5 volts or the full 5, so having the meter between 'em would do it.. if it's fast enough.

And if he does see the full 5 and knows the motor "works" off circuit, then hmm... think about my theory above..

 

[laatsch55]

voltage between 9,12 is .023 in all aspects.

 

[laatsch55]

Yeah Jer I l;ike your prognosis. I thought abouit the limit switch holding out tray movement after no motion wqas detyected ands facilitated tray movement at the right time. Also both of these CD-1's I have left had power supply fuses blown, I'm assuming from the 120, 240- switch being thrown the wrong way.

 

[jbeckva]

Ok.. crazy idea..

position tray so that it would normally open up with the button pressed

"hold down" (i.e. ground) pin 7, while pressing button

anything new and interesting happen?

 

[laatsch55]

pressing button to open or close

 

[jbeckva]

to open (not the same button?) hmm.. hehe

yeah.. hold down pin 7 with tray in closed position, then press open button.

 

[laatsch55]

Gotcha. Kevin is about to turn on his WOPL, hang on folks.

 

[Rex Everything]

Interesting read

 

[laatsch55]

Ok Jer, shorting pin 7 to pin 10, it moves the laser to the out position , no open.

 

[Gepetto]

Here is my recommendation for a quick and easy test of the TDA7073.

With everything static, no buttons pressed and all inputs and outputs steady at 2.5V, no motion.

Rig a 100 ohm resistor in series with a jumper clip lead, one end of this jumper attached to ground of the CDP, the other end will be the open lead of your 100 ohm resistor. Attach you scope lead to either pin 9 or pin 12 of the TDA.

First, touch the open lead of the 100 ohm resistor to pin 6 of the TDA. Note any change in voltage on scope or spinning of tray motor.

Second, touch the open lead of the 100 ohm resistor to pin 7 of the TDA. Note any change in voltage on scope or spinning of tray motor.

 

[Gepetto]

Looks like you are addressing wrong motor if it moved the laser head. Unless the TDA drives both and the chip is confused internally.

 

[laatsch55]

OK, hang tight.

 

[laatsch55]

That's operated off another 7073 up the board a bit.

 

[jbeckva]

Ok Jer, shorting pin 7 to pin 10, it moves the laser to the out position , no open.

Ok, that there is a BIG HMMMM...

We were all thinkin with 6-7 on the input and 9-12 on the output that this section of the TDA controls the drawer motor...

I'm thinking it controls the sled with the laser??

Lee. you're sure the drawer motor is on the other end of pins 9 and 12?

 

[jbeckva]

Looks like you are addressing wrong motor if it moved the laser head. Unless the TDA drives both and the chip is confused internally.

Lol.. like minds...

 

[laatsch55]

Yes it does jer, see the pic of the bottom of the board.

 

[laatsch55]

Joe, doing as you say we have the laser tray bottoming out and starting to strip[ gears, the other haven't found it yet but sounds like something else. Yep, both shortings of pins 6 and 7 make the laser tray move.

 

[Gepetto]

I think that the laser tray may move at the same time as the CD tray, I see a trace going off from pin 7 to another destination.