Replacing the draw cog and belt on CDM4/19 e.g. CD42/CD52

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The Valab TCXO arrived today for the CD52. Took its time I must say.

Still crunching numbers to optimise the 5v regs but have settled on making 3 using REG103's - one each for the analogue and digital supplies for the DAC and one for the Clock. I expect this to take the load off the remaining 5V digital stuff as well as reducing the overall current in the original transformer. I am beginning to think that anything else is past the point of diminishing returns.

But I am really enjoying the SQ improvement just from re-capping.....
 
CD52 mods

Finished the mods. Result is amazing and making my speakers (which are Manzanitas by the way) really sing. Finally piano sounds like piano and the Stones sounds like I am there. And its so clear, it really does sound live, well the good recordings anyway.

I'll have a figjam syndrome now for sure.

Summary of changes

New drawer cog and belt
Recapped the existing power supply with the biggest Panasonic, Nichicon or Rubycon caps I could find AND that would fit - essentially very tall, same diameter - about 25 of them all up.
Removed the capacitors across the rectifier diodes
Added snubbers across the transformer secondaries (780R + 100n)
(Now the unit is very quiet)
Added a second transformer 20VA 9+9 torroidal (careful to preserve the double insulation)
moved existing fuses to the primary side - the second fuse is now for the new transformer
snubbers across the secondaries (390R + 100n)
4 bridge rectifiers + largest smoothing caps that would fit (4700/35)
6 x uA78L05 regulators, 4 for the DAC analog, one for DAC digital and one for the clock
TCXO from Vintage Audio Labs in Taiwan
The 4 analog regs shared one transformer winding and the digital regs the other winding. My thinking is that the new transformer leaves plenty of VA without droop for the servo circuits on the original plus isolating the DAC from the pervasive digital noise.

Seems to work.

John
 
Thank you

I've just replaced the wheel/band on my Marantz CD52 MK2 Special addition using your instructions and it is now working perfectly.
I want to thank you very much indeed for your easy to follow instructions.

The only problems is that I have been left with a small spring about .5 of a cm long and .2 wide. It has flat ends with no hooks.
As everything seems to be working well I am content to leave well along unless the omission of the spring is desperate :)

Once again thank you so very much indeed.
 
Fantastic

Thanks so much. Piece sourced from the Far East for £5 and 15 minutes of labour. When removing the screw near the headphone socket I had to take out a second screw in the middle to move the facia but other than that no problems. Might I be the first woman to achieve this??? lol. Sarah
 
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