Musical Fidelity CDT Player

[contax]

Hello,

I own a Musical Fidelity CDT Player. It has a signal transformer in the begining of the tube output stage (see enclosed pincture. It's is a cube shielded with a metal sheet). One channel fails.

Temporary I have solved the problem connecting the stage without the transformer. I have inserted one capacitor and one resistor (the signal was too high) in the signal path and the player works again.

I would be interested in the service manual of schematic.

Does anyone know the transformer specifications?. Does anyone know what is the CD mechanism?

Has anyone modified this CD player?

Thanks for your help.

 

[contax]

I think the CD mechanism is a Sanyo SF-90 5/8. Does anyone know any details about the transformer?.

 

[tubenut]

Is it definately a transformer? Would not surprise me if the shield was the hiding place for some op amps.

WRT modding, these units are notoriously quirky, if it works otherwise, I would leave it alone.

 

[contax]

No. I think the shielded "brick" has two transformers inside. It has only three input terminals and three output terminals. One is ground and is common.

My "brick" has one channel faulty. I have tested the other one connecting a sinus wave signal and checked the output with an oscilloscope. The output signal is lower than the input signal.

Maybe the only purpose of the transformer is to supress any DC offset.

Without the transformer and inserting a capacitor in the signal path (before the output stage), the tube oputput stage and the CD work.

 

[molecule3]

Hello !

I bought this player and I like its vitality, I prefer it to my Arcam CD72.

It's hard to find informations on the Musical Fidelity CDT,
also known as 'Musical Fidelity PAN' (try this in google)

I do not know anything in electronics, but may be this link may interest you, or try contact 'dht' :

http://translate.google.com/transla...owe_cd_35158.html&sl=pl&tl=en&history_state0=

i speak english like a frog, sorry

 

[contax]

This is the power supply schematic published by dht

 

[contax]

and the output stage schematic

 

[contax]

The trafo picture. The DC resistance values are;

R primary = 5.93Kohm
R secondary = 86.40Kohm

The output signal/input signal ratio is aprox 0.7

 

[skibi]

contax,

unfortunately I dont have the service manual. I have only these two schematics posted on audiostereo. Maybe tomant could help you, send him a private message (PW) via audiostereo.
If you want to tweak the CD I suggest you to bypass the trafo and NJM4558 opamp. I can send you a LC7881 datasheet.

dht

 

[liesekarl]

Hi contax!

Do you solved your problem?
I have a Musical Fidelity "PAN" and my one has the same symptoms as yours.
Sometimes the faulty channel works fine.
When i heat up the "brick" it mostly works.

Can you help me?

Best regards

 

[02GF74]

regarding the schematic for the output stage;

does anyone know voltage for +va2, -va, +va1?

and what model valves are used?

plus any information on the input transformer?


thanks

 

[contax]

Hi contax!

Do you solved your problem?
I have a Musical Fidelity "PAN" and my one has the same symptoms as yours.
Sometimes the faulty channel works fine.
When i heat up the "brick" it mostly works.

Can you help me?

Best regards

My solution was the supression of the transformer. I inserted one resistor and one capacitor per channel in the signal path. I didn't remember the values. I can check it.

 

[vphifi]

I have the Musical Fidelity SACD player. It receives the power but never gets out out of the mute mode. No display on the front panel either. Does any one have the same problem and how to fix it?

Thanks

 

[tomtiger]

Hi,

I think the CD mechanism is a Sanyo SF-90 5/8. Does anyone know any details about the transformer?.

I often read it is a Sanyo SF-90 5/8 pin. There are several models of that player the one you (and I) have with the plastic lid is the older one, newer versions had a glass lid.

Mine has a spring loaded opening mechanism, I also read about hydraulic opening mechanisms (and their failures).


My CDT has a Sanyo SF-90 6/7 Pin laser pickup. Be sure to carefully check the pictures on the net before you get an exchange part, I got one from here: CD SF-90 6/7 PIN G?OWICA LASEROWA - www.100hz.pl

As for tuning, AFAIR the chipset used has an integrated oscillator so no clockupgrade should be possible.

All I did was to put textile tape to the places where the top covers touch metal supports.

As you can see here the mounting supports for the drive mechanism in my player are not black, I covered them in black textile tape where they are visible from the outside.

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

My CDT has shown another problem, the paint/coating gets off of the two top plates when cleaned. I have to see how I can solve that, but I would be careful (the first spots of colour got off when I had them in my ultrasonic cleaner).



Regards Tom

 

[contax]

Hello Tom,

The only fault on my CDT is the transformer. As per today I have not replaced it. Do you have any details about the transformer?

Thanks for your help

 

[contax]

Transformer replaced

Following Per Lundahl's advice I replaced the faulty Musical Fidelity transformer, choosing this http://www.lundahl.se/pdf/1570_0xl.pdf

It's necessary to build a small PCB in order to adapt the pins of the new transformer to the holes of the output stage PCB.

The sound should improve because I am sure the Lundahl transformer is better than the original used by MF.