My first CD50 mod with NOS

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#81
Eldam said:
😀... this April fool was gifted by Maccau ....😉😀

:cheers:
Click to expand...

:cheers: Eldam, thank you 😀 April fools is a good day and closer to May, then June winter 😀

The spare CD50 U shape heatsiink is loose so would be easy to take out with attached regulator, i think the regulator was upgraded in the CD50 I am working on. I will set meter to 500 dc and test output and input😱 and will be carefull not to touch wires
 
#82
Marantz CD50 no sound, one regulator gets very warm

I am still not getting sound, so i felt the regulators in the power supply and one was hot, if i left my finger there, so i got the spare CD50 board and replaced the regulator, but the same issue>😕 maybei need to get a new regulator?

😕
 
#84
Thank you Tauro for re reply and advice

Inside the heatsink, i get:

006 (6volt) reg going towards the front
the middle (2nd from back) is the hot one 015 (15v)
one at the back 011 ( 11volt)

outside attached to the heatsink is the other regulator
this reads 005 (5volt)

? maybe new ones for inside the heatsink?
 
#85
Hi,
Does the complete model number is the 74CD50? I found the services manual but is for the 74CD50. Can you read the part numbers on the board for the regulator? Anyway I checked the manual and it has 5 voltage regulators. If the part number is 6577 then the voltage output it is correct.

1-MC7805
1-MC7906
2-MC7815
1-MC7815
 
#86
Hi
I am looking now, i dont see 74CD50, but it is a Marantz CD50 player. ( edit -- yes service manaul says 74CD50)
I have the following.

Inside heatsink
6590 part number is the hot one, 78M15C (i think maybe factory mis print maybe 7815mc)
MC7906 -6v
MC7915 - 11v
MC7805 - 5v ( attached to heathink part 6591)
78M15C
 
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#87
Hi,
I download the services manual for the CD50 and it is the same. Do you have the service manual? If not download it by doing a search Marantz CD50 and check if it is the same as your have. If you have the manual check the voltages for all the regulators in page 14. The 6590 it is the 15 volt regulator.
 
#88
Hi i shall check now , and yes they are on page 14, the layout of the PSU , and i see +15 at the end of the arrow for 6590, not sure why it is hotish and the others are fine, maybe is a diode nearby, and 6v for the other reg is fine also
 
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#89
Each Regulator is supplying a specific Voltage at a specified Current. These will all be different and some will be supplying more current than others, therefore, they will get hotter. This is normal.

I am not saying you don't have a PSU fault but you need to do some basic, methodical checks.

What are the Voltages at the outputs of the Regulators compared with what the Service Manual says?

You say in post #5 ''.....MC7915 - 11v.....''
Does this mean you are getting Negative 11 Volts from this Regulator?
A 79.....Regulator is a Negative device.
A 7915 Regulator is a Negative 15 Volt device and if you are only getting -11 Volts from it, and this is the one that is getting hot then this is the place where you should look, after measuring all the other Supplies.
The Regulator maybe OK and just struggling to supply the correct -15 Volts because something it is supplying further down the line is faulty and wanting to draw more current than the Regulator can supply.
 
#91
Hi Percival 🙂
Thank you for the reply and help. This morning I did readings again, and I never saw any -ve readings i set the DMM to 500 on DC V--.

6593 - (back reg within PSU heatsink) : 7915C input 26V, output 11V
6590 - ( hot one to touch within PSU heatsink) : MC7815 input 23v, output 15v
6592 - ( within PSU heatsink) : 7906C : input 12v output 6v
6591 ( attached outside to PSU heatsink): 7805CT: input 11v output 5v (has attached tant cap 10v 35V)
6577 ( towards front outside PSU heatsink) : 7815MC: input 27v, output 5V


Hi Tauro
CD plays perfectly, there is no sound output though, and that one regulator in mention seems hot the touch? i have tin can version of the LM4562
 
#92
Hi,
The 6577 the output should read 28 volts. It's have a zener diode in the pin 2 that will raise the voltage 15+13 = 28. But thats goes to the VFTD. Also the sound output it is disable by the signal KILL. I tied to find where it is coming from but can not find it. If you find it should read zero. A positive will kill the output.
 
#93
Hi thanks for explaining Tauro
I get 27v, means maybe i just need to check it again. I need a zero reading, if can find the signal KILL. I wonder if the opamp is the problem? the pins on the tincan LM4652HA is thinner than the other LM4562 where were in the adaptor socket.
 
#96
tauro0221 said:
Hi,
Can you check the transistor base 6542 voltage? Page 20. if you have a
positive means something it is telling to kill the output.
Click to expand...

tauro0221 said:
Hi,
I think I found where it is coming from. It is in the same page coordinate H-12 and V-F. It is generated by sine wave 1 and 2. Same page. We need to check the kill signal to decide what to do next.
Click to expand...

Hi 🙂
I will get the marantz back on the table, and check what you said and report back. I would use dc voltage like the regulators.

I have to find 6542 first, then try to find H12, but first the transistor
 
#97
2ew16qh.jpg


? is this the 6542 transistor? it is near the 2700 ( bp capacitor) 100u 16v

how do i measure the transior? earth on the rca and +ve on the base

thanks again Tauro 🙂 off to lunch then back on the Marantz
 
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