Bram Jacobse

Tinkering CD Players & Digital Audio

CD 100

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If i could take a look at this CD 100 , it’s been recapped , Also the MAB C006 has been Replaced. LM324 and  other Op-amps have been replaced , Servo BD135 and BD136, some Diodes…  but still not working, 🙁

 

 

 

 

 

 

 

Problem found,  a broken TCA240

 

 

Some comparisons measurement off the TCA240 in a CD 104 in Service mode A

Measuring : the yellow trace is output Radial Error (RE) output LM324 pin 8 ,Purple is i1+i2+i3+i4

 The radial error signal RE applies the formula:
RE = k.d. (i1 + i2 +i3 + i4) – k (i1 + i2).

k is controlled by the automatic gain control
d is controlled by the offset control

A good TCA240

 

The Broken TCA240 ,  K or D is wrong

 

And here startup sequence ( scope in rolling mode )

Start of CD and begin first track

The good TCA240

The Broken TCA 240

 

 

“It’s fantastically beautiful, analog sound!!! Once again, thank you very much! , I listen to music on CD 100 all day, it’s a fantastic experience!, I  think it could have been standing there somewhere for years. Now that you’ve brought it to life and I’m using it, it just keeps getting better. Thank you very much!!!”