Primare laser change

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The measurement of approximately 1.5 volts pk to pk is as viewed on a scope. There's no other way to do it. If its difficult to access then you can solder a wire tag to connect the probe to.

It does sound like a suspect pickup. Even 6 years or so back I returned two CDM12.4's back to the supplier (I won't name them but they are one of the biggest suppliers to the repair trade). I was sent a boxed "Japanese" made CDM12.4 mech that was absolutely unbelievable in quality. The RF was amongst the cleanest I have seen. The other pickups looked and even smelled used and dirty.

No easy answer I'm afraid.

Are the "made in Japan" versions NOS or are there in Japan the CDM12.4 laser pickups still under currently production ?

check out also this threads:
http://www.diyaudio.com/forums/digi...ayer-models-loader-l1265-l-1265-cdm-12-a.html
http://www.diyaudio.com/forums/digi...am1254-cdm12pro-vau1254-cdm12-4-compatib.html
http://www.diyaudio.com/forums/digital-source/118902-stripdown-clean-cdm12-4-a.html
http://www.diyaudio.com/forums/digi...dm-12-4-transport-compatible-replacement.html

P.S. this Primare model is very similar to Thule's model CD150 (Spirit) where the loader model L1265 from the Philips model CDR765 is in use - go to post #14 about
http://www.diyaudio.com/forums/solid-state/180929-thule-audio-components-overview-2.html
 
You would normally measure here (for example) on pin 8 of the SAA7345 (assuming thats what it uses)

Find the 2K2 resistor and clip the probe to that.

finally found some time and attached a wire to 8th pin of SAA7345 (1st three pics). The last pic is 9th pin of TDA1305 soldered to ribbon cable socket (was 10th before). I don't know, seems to me like same graphs as I uploaded above :confused: Moreover, when attached to SAA chip, pk 2 pk voltage is reduced by 10% roughly...

P.S. this Primare model is very similar to Thule's model CD150 (Spirit) where the loader model L1265 from the Philips model CDR765 is in use - go to post #14 about
http://www.diyaudio.com/forums/solid-state/180929-thule-audio-components-overview-2.html

same company same parts and design, different chassis :)
thanks for the links, I got the point, the only trouble is where to get a decent CDM12.4 laser...

Well, it's not so bad actually though it skips on scratchy CDs... The only thing is to try another laser head, perhaps I would be more lucky next time. Alternatively I'll use some grease from the old mechanism as the new one came without any.

Also would be very delighted to correctly take pk 2 pk measurements as it seems i'm doing smth wrong...
 

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It seems like the digital scope can't resolve the waveform, it shouldn't look like that :) If that's the case and I wouldn;t like to say whether the amplitude can be relied upon either.

The level decreasing when on the 2K2 resistor will be due to scope loading due to probe and cable capacitance. At high frequencies those effects become dominant. A divider probe (divide by 10) reduces that effect a lot.

Getting a good CDM12.4 is a problem. Remember these are nearly 20 yr old now.

Another thought is when you describe "scratchy" discs. The CDM12.4 was never great at coping with such discs in the real world although a good one passes all the red book tests and more.

Post #54 here,
http://www.diyaudio.com/forums/digital-source/67783-test-cd-cd-player-adjustment-3.html#post1415445
 
Getting a good CDM12.4 is a problem. Remember these are nearly 20 yr old now.
There is only one me known source to get an excellent CDM12.4 head:
Buy the mechanism from Marantz' CD7, model VAM1252. Unfortunately Marantz don't offer the head alone - only the whole mechanism for 250 until 300 euros (as replacement part, definitely NOS and not from currently production).
 

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Another thought is when you describe "scratchy" discs. The CDM12.4 was never great at coping with such discs in the real world although a good one passes all the red book tests and more.

Post #54 here,
http://www.diyaudio.com/forums/digital-source/67783-test-cd-cd-player-adjustment-3.html#post1415445

ok, then I leave it as it's now adjusted roughly to 1.5vdc p2p on 9th pin of TDA1305. Thanks again for the help ;)

There is only one me known source to get an excellent CDM12.4 head:
Buy the mechanism from Marantz' CD7, model VAM1252. Unfortunately Marantz don't offer the head alone - only the whole mechanism for 250 until 300 euros (as replacement part, definitely NOS and not from currently production).

I wish I said I have at least that hope, but it's way too much for used Philips head :)
 
cheers,

it took quite a long time for me to make sure that all gained copies from ebay are real cr%^& and even the so called genuine parts that have some stamps and even rust do also skip tracks or do not read anything after the first couple of tracks at all. That is a nightmare :)

anyway, there is one thing that forced me to post it here.

I installed a genuine cdm laser in my primare taken from other well working player that was used to compare the readability of all these Chinese copies. It worked for several days having no issues at all like when it was in the other player. Then yesterday in the morning it instantly began to skip almost every track on 50% of CDs. The laser had been accurately cleaned before I swapped it to Primare. Anybody knows what that thing is? Does that mean that the laser is going to die or the primare is so good that even the original cdm cannot help it?
 
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I wouldn't like to say what is going on tbh. Once you have started fitting different pickups and are still having problem then a thorough investigation is called for. And this is where proper test equipment is called for. The RF signal is the biggest clue and it should look like this on a scope (pictures 8, 9 and 16) irrespective of the pickup/mech type. The CDM12.4 signal should look identical to picture 16 apart from amplitude which could be a little higher on the 12/4

http://www.diyaudio.com/forums/digital-source/226288-sony-cdp790-kss240-restoration-project.html
 
Thanks again, Mooly, for your help :)
It's really something fishy going on with the player as today it read all CDs without even a tiny skip. It was disconnected from the mains for couple of days, though i doubt that it could be the reason. Anyway, I'll continue my observations :)
 
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