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Old 9th April 2005, 06:06 PM   #1
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Question CDM9 Tray Motor Overrun

Hi All,

I've had a look but can't find any archived info about the tray motor overrunning on a CDM9 unit when the tray is closing.

I have checked the limit switch and this seems to be working fine.

The problen occurred after I had re-capped the CDP with Pana FC and FKP caps (in the same values).

A look at the service manual didn't really help - the cap that is in the tray control part of the circuit is not one I changed.

Many thanks in advance for suggestions.

Jon
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Old 10th April 2005, 05:53 PM   #2
tubenut is offline tubenut  South Africa
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Motor over run.. I assume you mean the motor keeps turning for 3 secs after the tray is closed and disc loaded in place?

My Theta Data obtained 2nd hand had a 10 ohm resistor fitted on the tray motor + motor terminal. Thought this was to slow the tray down and make it look more "deluxe".

I recently fitted a new tray gear to another Theta data and it had the motor over run problem... I cleaned the switch 10 times.... And reconditioned the belt, cleaned, sanded, cleaned gears etc...

There was no resistor on the motor on this one... Finally I put 10 ohms in series with the motor supply and the problem vanished.. Except now every 3 or 4th load it would not read toc.
Played with resistor values and got down to 3.3 ohm, no motor over run and reads toc every time a coconut.

I do not have a clue to the reason for the problem or why the resistor works. If anyone knows what the reason for the problem is I would be keen to know 2.

Jon, for now a resistor in series with the motor (fitted on the motor terminal) will probably solve your problem.

Keen to hear if anyone knows more....

regards
Guillaume
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Old 10th April 2005, 08:08 PM   #3
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Lightbulb Thanks Guillaume.......

.......... I'll give that a try.

I don't know it this makes any difference, but I mis-posted the problem - it happens when the tray is opening, not closing. It is for around 2-3 seconds, and I don't recall seeing any resistor when I had it in bits this weekend. I've now reassembled it, but it'll be open again soon to fit a Kwak Clock 7.

According to the scematic, as the limit switch is made, the +5V or -5V motor run voltage drops to zero and the tray stops. I can only think that a cap change I made is interfering with the motor run logic and it is thinking it needs to go for a few secs more. I replace Evox Rifa PFR with FKP and Rubycon with Pana FC - all like for like values.

Thanks for you suggestion.

Cheers

Jon
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Old 8th May 2006, 01:32 PM   #4
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Question Update.... But no joy

Hi, I was hoping an update to bump this thread might just catch someone's eye out there.

I have finally got round to dismantling the player again and having a really close look at the schematic (with my limited electronics experience). The tray limit switch only seems to be employed while the tray is closing. I can short out the switch pins on the mainboard (simulating limit switch closing) and the tray stops dead. I am measuring +7V closing and -7V opening and the schema lists 5V.

Playing with the limit switch shorting has no effect on the -7V tray opening which seems to runn for a predetermined time (around 2 secs too long) and then the motor stops. I didn't get round to putting the resistor on the motor and am hoping that a fresh look at this might help. I am holding off putting back all the caps I replaced, but I have retained them all. I have a feeling that this problem will still be there when I have finished soldering and would prefer not to retrace my steps just yet!!

So, apart from the resistor on the motor (which I'll try anyway), does anyone have any other suggestions?

Most grateful for your thoughts.

Many thanks!

Jon

PS: I have a pdf service manual that I can email over if you'd like a look. The relevant part of the circuit is on sheet 4 "Alpha 5 CD Monoboard Circuit".
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Old 8th May 2006, 02:28 PM   #5
poynton is offline poynton  United Kingdom
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Default Re: Update.... But no joy

Quote:
Originally posted by jonclancy
Hi, I was hoping an update to bump this thread might just catch someone's eye out there.

I have finally got round to dismantling the player again and having a really close look at the schematic (with my limited electronics experience). The tray limit switch only seems to be employed while the tray is closing. I can short out the switch pins on the mainboard (simulating limit switch closing) and the tray stops dead. I am measuring +7V closing and -7V opening and the schema lists 5V.

Playing with the limit switch shorting has no effect on the -7V tray opening which seems to runn for a predetermined time (around 2 secs too long) and then the motor stops. I didn't get round to putting the resistor on the motor and am hoping that a fresh look at this might help. I am holding off putting back all the caps I replaced, but I have retained them all. I have a feeling that this problem will still be there when I have finished soldering and would prefer not to retrace my steps just yet!!

So, apart from the resistor on the motor (which I'll try anyway), does anyone have any other suggestions?

Most grateful for your thoughts.

Many thanks!

Jon

PS: I have a pdf service manual that I can email over if you'd like a look. The relevant part of the circuit is on sheet 4 "Alpha 5 CD Monoboard Circuit".

Hi.

I take it that the problem is in an 'Alpha 5'?

Send me the pdf and I'll take a look.

Andy
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Old 8th May 2006, 06:20 PM   #6
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Thumbs up Thanks!!

Hi Andy,

It's an Alpha 6 but the main board is the same as the 5 and 5+.

I'll PM you the Service Manual when I get to my other computer later on this evening.

Many thanks for your help!!

Jon
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Old 8th May 2006, 06:26 PM   #7
poynton is offline poynton  United Kingdom
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Default Re: Thanks!!

Quote:
Originally posted by jonclancy
Hi Andy,

It's an Alpha 6 but the main board is the same as the 5 and 5+.

I'll PM you the Service Manual when I get to my other computer later on this evening.

Many thanks for your help!!

Jon
Hi. Fine.

If it is very big, it may be better to post it to :-

http://www.yourfilelink.com/

and email the link.

Andy
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Old 9th May 2006, 11:23 AM   #8
poynton is offline poynton  United Kingdom
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Default Re: CDM9 Tray Motor Overrun

Quote:
Originally posted by jonclancy
Hi All,

I've had a look but can't find any archived info about the tray motor overrunning on a CDM9 unit when the tray is closing.

I have checked the limit switch and this seems to be working fine.

The problen occurred after I had re-capped the CDP with Pana FC and FKP caps (in the same values).

A look at the service manual didn't really help - the cap that is in the tray control part of the circuit is not one I changed.

Many thanks in advance for suggestions.

Jon

Hi Jon,

Thanks for the manual.


I have just checked my A6.

The motor voltage is almost the same as yours +-6.4v.
Looking at the schematic, I don't think that is anything to worry about. The driver chip is fed from the unregulated nominal +-10v.

On tray out, the voltage remains high for about 1 sec before returning to 0v.

On tray in, it returns to 0v immediately due to the switch.

The motor stops dead, by the way. No sign of run on after the tray is all the way out. [although as said there is voltage for a second after it stops]

If yours keeps running, try cleaning [degreasing ] the belt and pulleys, it may be greasy.

Alternatively, try the resistor.


Andy
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Old 9th May 2006, 08:03 PM   #9
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Hi Andy,

Thanks for following up my measuments on your own unit. It is feasible that the belt could be greasy. I changed the geared wheel on this unit and used a silicone grease. Quite possible that it went where it shouldn't have.

If that doesn't do it, I'll try the resistor to slow the motor down. That way the time and tray position might just coincide somewhere near the end of the tray travel.

Again, many thanks for your assistance here - I appreciate it.

Jon
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Old 11th May 2006, 07:29 PM   #10
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Cool Success!!

Hi Andy and Guillaume

SUCCESS! I tried a variety of resistor values. Eventually settling on 22R5. The motor runs smoothly and doesn't overrun.

Thanks very much indeed for your help Gents - I'd be stuck without it. The forum doesn't show the large amount of PM traffic between us in discussing this problem and I appreciate your time.

Hopefully, anyone else with this particular problem can find a quick and easy solution in this thread.

All the best

Jon

Can't work out why it overran in the first place, though.....
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