Help! CONRAD JOHNSON DF1 CDplayer-preamp

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... Unfortunately the display driver IC and the seven segment displays here is one module (one unit)
... the great effort.

I think it would be better to stop all that.
One digit lost on display is not a great problem.

The best is it plays music now !!

DiyAudio is very nice to find help and knowledge.
These 3 last weeks - and thanks to You - I repaired My Conrad Johnson DF1 and my Kenwood L-07CII.

Raymond
 
... What are the analogue stages like that CJ add. Any room for improvement there ? Opamps maybe ? What does it use.

It's a pure CJ product for D/A section & preamp stage :
- on the upper right, you have D/A stage card,
- just below (invisible) preamp section with many selected Jfets,
- and just behind led numeric display a second power supply ( CJ made ) dedicated for these 2 stages.

An externally hosted image should be here but it was not working when we last tested it.


And in addition this link about DF1 CONRAD JOHNSON

Raymond
 
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Thanks for the detailed picture... sounds like it is discrete from what you say.

It's a really nice player... worth looking out for a display for.

Really, I bought it recently and I never listened it.
Today I will do it thanks to you.
But I think nowadays CD players are better, and the main interest of this DF1 consists it is a preamp with 2 line inputs.

An externally hosted image should be here but it was not working when we last tested it.


And I am not yet ready to put my LEVINSON set ML-6A / ML-2 in my cellar !

About its numeric display ( block with its ic decoder ) , I think it is a selected CJ component ( not Philips because its 9 pins on the same row ) :

An externally hosted image should be here but it was not working when we last tested it.


Raymond
 
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Hi... you're English is fine :)...

Oooooh, I don't think so !
It's my dictionary.

Conrad Johnson tested this morning.
As said previously :
- CDplayer is just average ( my Sony CDP-X555ES beyond all question better )
- but preamp section is very nice ( a bit tuby with rich bass & medium ), typically CJ, but not enought to put my Levinson ML-6A in the cellar.

About led display Metaxus said : I just repaired the display on a newly acquired CD202 tonight by flowing solder through all the vias.
And I did't understand the meaning of " all the vias" : Help me please !


Raymond
 
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Vias are all the little empty "holes" on the display PCB that are plated through. They link one side of the board to the other.
I wouldn't like to say whether that would be worth trying or not. Maybe the heat from doing that affected it... dunno ? my feeling is it probably won't be that... and that if it did alter the fault it's because of the heating that took place.
Can't really advise on that... worth a try if you are careful perhaps.
 
Oooooh, I don't think so !
It's my dictionary.

Conrad Johnson tested this morning.
As said previously :
- CDplayer is just average ( my Sony CDP-X555ES beyond all question better )
- but preamp section is very nice ( a bit tuby with rich bass & medium ), typically CJ, but not enought to put my Levinson ML-6A in the cellar.

About led display Metaxus said : I just repaired the display on a newly acquired CD202 tonight by flowing solder through all the vias.
And I did't understand the meaning of " all the vias" : Help me please !
Raymond

The term "VIA" (= "Vertical Interconnect Access") I have never heard before (I know only the term "throu-hole" for that). Now I know, what this mean;
Via (electronics) - Wikipedia, the free encyclopedia
Through-hole technology - Wikipedia, the free encyclopedia

To perform flowing solder through all the vias is a good idea. Sometimes transition resistances by the vertical interconnections causes trouble in general. Such trouble is always hard to find.
But remove all oxydations and solderstop coating residues with help of a fiber pen carefully before solder.
 
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.. Maybe the heat from doing that affected it...
Can't really advise on that... worth a try if you are careful perhaps.

I have the same idea about that.
May re-soldering have a repair action or a killer one ?

I think problem is rather due to a bad junction between 4 numeric block and its PCB plate : this junction seems to be executed by heating small plastic pins of this block which stick it on the PCB.

One rule to do in the life : when we don't know, we don't touch !!!

Raymond
 
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Lol... something like that :)

Would you believe, my ancient Philips 150 has developed the same display fault as yours... it didn't want to be outdone.
I only use it as a quick source component on the bench so no real problem.

I'll wait and see how you fix yours ;)
 
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