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Trying to fix a Kinergetics Research kcd40
Trying to fix a Kinergetics Research kcd40
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Old 17th January 2018, 01:36 AM   #1
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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Default Trying to fix a Kinergetics Research kcd40

I guess you can say I made the foolish attempt to replace the 8809 and 8808 IC's and then try the player out without making sure nothing else was bad or getting trouble shooting advice first.

I saved the player form the trash in the hopes of fixing it for a client. It would not spin a disc at all, it attempts to but does a sort of one, two step with the disc then nothing.

With past experience I have found that the laser is never the problem rather a bad spindle motor, bad connection on the board or a servo IC.

This player has a philips mechanism and board and philips IC's. I was able to source the TDA8808 and 8809 IC's on ebay... they look like the real thing or really good fakes, either way upon the first read with the new IC's the disc read out and spun up and played for about 5 seconds then the laser sled flipped "hard" to the end of the tray.

Now I'm back to the old problem... and possibly bad IC's again if they were bad in the first place. I was hoping some one might have a schematic for this player or have some idea were to find the "RF" test point and what the two adjustment pots on the board can do for me.

Any help or ideas would be greatly appreciated! (otherwise the player really is going in the trash)
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Old 17th January 2018, 01:55 AM   #2
Praudio is offline Praudio
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Is it a CD4/19 or ?
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Old 17th January 2018, 05:03 PM   #3
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
Does this use the infamous Philips 33uF radial (edit... Axial, not radial) caps that cause so many problems on other players ? If so then they would be favourite to replace first.
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Old 17th January 2018, 10:00 PM   #4
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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The player is a KCD-40, I have no idea what model the philips board and mech are used in.

I found one philips 47uF 25V axial cap which read around 25uF so I swapped that out. All the other capacitors are Nichicon radial lead types.

I tried a cd again and it attempted to spin it up, this time I heard the laser sled snap over almost right away and the cd just sat there spinning lol

The first time I tried a cd with the new IC's I actually got a read out time and play time on the disc up to 5 seconds. The screen stays blank now.

Did some more probing and found a TCA0372DP2 14 pin servo amplifier opamp which appears to be driving the the laser sled coil. It looks like it took a little bit of heat on the board... could this be the real culprit or am I chasing wabbits again?

Not sure if there is a sub for this part... if pictures would help I can work on taking some.
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Old 18th January 2018, 07:40 AM   #5
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
The chip is a dual power opamp... I doubt that is the problem tbh. If the outputs are behaving normally (as in following normal opamp rules) then it will be fine.

Is there a separate servo board under the RAFOC unit ? That is where all the problem caps live in other Philips players. I'm not familiar with this one beyond pictures on the web but it looks to be based around second generation Philips era stuff judging by the mains transformer.
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Old 18th January 2018, 09:05 PM   #6
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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Quote:
Originally Posted by Mooly View Post
The chip is a dual power opamp... I doubt that is the problem tbh. If the outputs are behaving normally (as in following normal opamp rules) then it will be fine.
Can I check the outputs with the scope? What should I see if the opamp is working?

I will get some pictures of the full board up.
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Old 19th January 2018, 01:54 AM   #7
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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New TDA8808 IC (underside of board)

Click the image to open in full size.

New TDA8809 IC (underside of board)

Click the image to open in full size.

Full board with original Philips DAC removed.

Click the image to open in full size.

Close up of section with the TCA0372DP2 opamp and laser assembly connector. You will notice that I have all ready replaced some capacitors including the 47uF Philips axial lead one I mentioned earlier.

Click the image to open in full size.

The custom DAC board.

Click the image to open in full size.

Underside of laser assembly.

Click the image to open in full size.

Last edited by CrazzyAbtTubes; 19th January 2018 at 02:01 AM.
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Old 19th January 2018, 07:57 AM   #8
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
Quote:
Originally Posted by CrazzyAbtTubes View Post
Can I check the outputs with the scope? What should I see if the opamp is working?

I will get some pictures of the full board up.
It doesn't quite work like tbh. The opamp output could be in any one of a number of states, a static voltage, stuck at one rail or the other, or with an AC signal on it.

What it does do is follow rules regarding how it is arranged with regard to how the feedback around the opamp is configured, and what the applied input voltages are around the inputs.
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Old 20th January 2018, 06:59 AM   #9
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
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All right, well what is the next step I should take to trouble shoot this problem? If you don't think it is that opamp what should I look for next? It would be nice to know what the two pots control and of course a schematic is probably not easy to find for this player!
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Old 20th January 2018, 07:53 AM   #10
Mooly is offline Mooly  United Kingdom
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Trying to fix a Kinergetics Research kcd40
A manual is pretty much essential tbh. You might get lucky trawling all the Philips models of that era because that main PCB is almost certainly from a standard player.

If you can still get it to spin up and read the TOC or play even for a second or two then that's enough to look at the RF on a scope and make a judgement call on amplitude and quality.

One of the pots will probably be laser current, the other perhaps some offset adjustment related to the servos.
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