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Trying to fix a Kinergetics Research kcd40
Trying to fix a Kinergetics Research kcd40
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Old 21st January 2018, 04:30 PM   #11
ahiukka is offline ahiukka  Finland
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Main PCB looks really close to Philips CD380.

Maybe the circuit has some very minor differences, apart from "missing" DAC, but most likely it is essentially the same.

Service manual for Philips CD380:
PHILIPS CD380 Service Manual download, schematics, eeprom, repair info for electronics experts
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File Type: png Philips.CD380.PCB.png (191.4 KB, 36 views)
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Old 22nd January 2018, 12:40 AM   #12
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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*edit*
Thanks ahiukka! that is in fact the player I was looking for! A CD482 was pretty close as well but had a different DAC TDA1543 I think.

I was also looking at the data sheet for the TDA8808 to see where I should attempt to grab a signal from if I can get the player to read a disc again.

Pin9: FOCstart Pin16: FElag Pin18: LM which has the "monitor photodiode" Pin17: is LO which goes to what looks to be the CCS driving the laser diode.

I lack the knowledge behind the theory of how it all works other than the basics so this is a bit of a learning challenge for me right now.

Last edited by CrazzyAbtTubes; 22nd January 2018 at 12:43 AM.
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Old 22nd January 2018, 06:53 AM   #13
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
Pin 3, HF out is the RF signal.
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Old 24th January 2018, 01:38 AM   #14
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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Well I tried to measure the RF signal and got it trying to read out once and for a moment I saw something on the scope but it was so brief I wasn't able to even tune in to see what the wave form looked like.

The player seems to be doing a "read out" of the cd less frequently now. There is no pattern to the problem it seems.

I set the laser adjustment pot to 1K which is what the service manual says to start with and the "focus offset" to have the lens close to the mid way point. This indicates that this section of TCA0372 to me is working at least.

Pin 3 is the output output to the radial motor, on idle there is 1.86V present and the voltage hops around when the player tries to read a disc. This voltage have been skyrocketing when I heard the radial motor "snapping" to the limit point, I was hoping I could get a reading of the signal coming out of the opamp when it did that.

Have any more ideas Mooly? I'll see if I can get the player to read out again and put out an RF signal but it isn't looking good right now. Not sure how much more time this player is worth spending on but it is starting to look like it might be going to the grave yard.
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Old 24th January 2018, 07:35 AM   #15
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
No magic fixes I'm afraid. If it tries to read a disc then it means that electronically it is basically OK at a fundamental level.

Adjusting pots on a non working player introduces even more variables into the equation.

If you can get the RF to appear, even if its not locked on the scope, then you should be able to gauge the amplitude which is always useful. Around 1.2 volts pk/pk would be normal.
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Old 24th January 2018, 09:05 PM   #16
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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If I leave the player sit for a day now I can usually get it to spin up once or twice if I am lucky.

This is the best I can do for now... just looks like a bunch of noise. I had it set at 0.2V 0.5uS but I never really learned how to properly use a scope so the measurement is probably not accurate.

Click the image to open in full size.
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Old 25th January 2018, 07:26 AM   #17
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
Hard to say whether just noise or not.

If it is set to 0.2V/div then the level is really low. The 'Cal' knobs all need to be set to the 'Cal' position for the settings to be accurate. You need to set the trigger to be active on the scope channel being used (CH1).

You can get an idea of whether it is noise or not by carefully tweaking the laser power and seeing if the level alters. You've already altered this setting and so nothing lost in trying it on the scope.

Use AC coupling on the scope but before you measure again make sure you understand how to read the amplitude. If you set the coupling to DC then try measuring a 1.5V battery and check the trace moves around 8 divisions vertically (for the 0.2V/Div range. You will have to move the trace right down to bottom of the screen to fit it in.
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Old 25th January 2018, 10:49 PM   #18
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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Ok, I got it figured out now, I got the same sort of noise but on 0.5V and is around 0.75 p-p. Tried a couple of time settings and there was no real distinguishable difference... just noise.
Quote:
You can get an idea of whether it is noise or not by carefully tweaking the laser power and seeing if the level alters. You've already altered this setting and so nothing lost in trying it on the scope.
Wish I had more time to work with to actually try tweaking with the laser power setting but I guess if I change it a bit I can tell if the level goes up or down or if I literally just have noise.

I'm still suspicious of the TCA0372 since I have seen intermittent/bad opamps do some very strange things it would be nice to know how it would affect the player is it was going bad... I do have a SOIC version on hand but would have to get an adaptor or hard wire it but I trust that you don't think that is what the real problem is so it would just be a blind assumption for me!

An odd thing I forgot to mention too is that the tray motor spins to pull the tray in as if it is not detecting the tray is closed just before the player attempts to read out a disk. I checked the functionality of the door switch and the player detects when the door is open or closed without problems. I also swapped out the switch for a good one and there was no difference.
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Old 26th January 2018, 07:28 AM   #19
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
It sounds like there is more than one issue here. The tray motor should not be running at any time once a disc is loaded.
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Old 27th January 2018, 01:38 AM   #20
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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The tray motor spins when I hit "play" then the spindle sort of "twitches" clockwise a bit then counterclockwise.

I did manage to get it to start playing the first track again for a couple seconds and was able to grab a much better shot this time before the player went into maximum overdrive and came to a slow hault.

Click the image to open in full size.

It seems to be pretty consistent with not working after this point, almost like something cools off or discharges allowing something to work for a brief period of time.
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