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Old 7th August 2013, 03:49 AM   #11
Johno is offline Johno  Australia
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Default CD-52 laser and focus adj without test discA?

@SimontY, many thanks for documenting the process, its still being used. Pity you do not get royalties, I would have been happy to pitch in.

My story, I have just purchased a dead CD52 for restoration and tweaking.
Quick check showed lots of litter from the broken gear wheel as I expected. I have since bought a replacement wheel and belt from Marcmart in HK on eBay.
Unfortunately I also found that someone had been inside it before me, to the point of removing the main board. Nothing was changed thankfully. However, when this moron put it back together he inserted PCB mounting screws into the holes for the laser and focus trim-pots, tightened them until the trim-pot end stop broke, jamming the screw in the hole. (now I know why 2 cover screws were missing).

I have the service manual which describes the fairly simple adjustment process.
But, do I need to acquire the test CD 5A? Does anyone have experience with laser current adjust and focus offset adjust without the test disc, are there any tricks?

Many thanks in advance....

John
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Old 8th August 2013, 06:25 PM   #12
SimontY is offline SimontY  United Kingdom
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Hi John,

I adjusted the laser current on a similar player once and I had no specific test disc. I think I just used normal music... no tricks or tips as I can't remember a whole lot about it, I just followed the instructions and it seemed to work ok.

I'm glad the guide is useful :-)

Simon
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Old 12th August 2013, 06:02 AM   #13
Johno is offline Johno  Australia
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Thanks Simon,
Have not tried the adjustments yet, i am stripping it down for a clean and tweak.
I decided to separate the 5 and 10 volt supplies by adding a small 20va toroidal mains transformer for the 5V digital needs and increasing the pre and post regulator filter capacitors along the way. Plan to use separate 78L05 regs for each of the 5 DAC power pins and a 7805 for the rest of the digital chain. Any other 5v can run off the existing supply thats shared with the servo. The 15v analog supplies will just get bigger caps and I have pulled the 5532's to replace with LME49720 but will DC couple the outputs. Then there's the oscillator and and and ..
Cheers
John
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Old 14th August 2013, 04:22 PM   #14
SimontY is offline SimontY  United Kingdom
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Hmm, good mods, it should sound really nice, especially if you re-clock it. There's always more isn't there?!

Simon
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Old 16th August 2013, 11:32 AM   #15
Johno is offline Johno  Australia
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I found the low jitter vcxo from Vintage Audio Labs in Taiwan to do the reclocking, so thats now on order along with the caps and regulators and stuff. All due to arrive next week.

I have moved the existing fuses from transformer secondary to the primary side now that I will reduce the load on the existing transformer (surprising amount of heat marks on the inside of the top cover). There are pads on the main board for one mains fuse (was jumpered) so regrettably I will drill holes nearby for the second fuse to protect the second transformer.

That unfortunately gives me 240Vac wires running from the left hand side of the box to the vacant realestate on the right hand side. Can't see any way to avoid it.

And I have promised myself, that will be all.
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Old 16th August 2013, 04:57 PM   #16
SimontY is offline SimontY  United Kingdom
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Interesting stuff. I've had my eye on VALabs' gear on Ebay for a while... the clock, DACs and the stepped attenuators in particular.

Do let us know how the clock sounds in the '52!
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Old 28th August 2013, 04:21 AM   #17
Johno is offline Johno  Australia
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Very happy with step 1. Gave it a good listening to then a service/clean/re-grease, re-adjusted laser current and focus after replacing all the power supply electrolytics, with a bit of a squeeze to miss the case work and each other.

the +/-15v smoothing were 100/35 are now 2200/35 FR
the +/- 10v were 1000/16 and 3300/16 are now 6800/16 HE
and 21 of the 47/25 scattered post regulator are now 470/25 ZLJ
the op amps are now LME49720 in sockets.
the bypass caps across the rectifier diodes replaced by snubbers on the secondaries, 100n+780R

Result is a remarkable reduction in noise and hiss and hum, its embarrassing how much because I thought it was pretty good before.

Really annoyed by the errors in the Marantz service manual - so many of the references do not line up with the CD52 that I could almost have cooked it.

Still waiting for the Vlab clock but have got my hands on some REG103/104's plus some LT3032's. Both have very good noise and load transient specs but the 3032's are far too small for my eyes. What was I thinking?

Last edited by Johno; 28th August 2013 at 04:23 AM. Reason: missed a bit
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Old 30th August 2013, 08:22 PM   #18
SimontY is offline SimontY  United Kingdom
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Outstanding! I do like the sound of these players, they can sing quite nicely, though I've not really gone to town on one. I may do one at some point, just for fun!

What brand of caps are FR, HE and ZLJ?
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Old 31st August 2013, 12:08 AM   #19
Johno is offline Johno  Australia
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Oops, assumed you would know
FR = Panasonic, HE = Nichicon and ZLJ = Rubycon.
All 104C, high current (plus 0.8 or 1.0mm lead diam), long life and are tall, narrow with small pitch which makes them ideal for retrofit with much larger values.
I prefer FR and FC but they get expensive, and personally I think these are better than the Elna caps.
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Old 31st August 2013, 07:21 AM   #20
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Tall, narrow and small pitch are awesome things as it's often so hard to squeeze in larger capacitance values!
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