Yamaha CS50 No sound generated
When I received it the voltages were bad or missing. I rebuilt the power supply. All voltages good at the load end. With the volume all the way up, I get noise. I can hear a faint generated sound with some settings, but it doesn’t change with key change. I have multimeter and scope.
Yes. + and - 15vdc and + and -15s and + +8.5vdc and 6.5 vdc. I found 2 TA7505M TO3 IC’S that are bad and are order. Can you explain their function??? I see 6 keys sending voltage to the YM26000.
Thanks for your response. I am in way over my head on this but then, how do we learn???/ again thanks
Hmmmm … where do you see TA7505M in TO3 casing? I can see TA7504M in TO-18 and that is an OpAmp used on the Master Board Transposition Circuit
It seems to me that we are looking at 2 different versions of the cs50 schematic. Mine shows the keyboard into the KAS board, into the SH BOARD (Sample/hold).The SH board has 4 of the TA7505M TO- 8 PIN CAN OP AMPS (MY MISTAKE) IC chips and 4 on the KAS board. AGAIN, thanks for weighing in on this for me.
It’s not the TO3. Sorry I am a little slow at this. The mosfets on both the SH and the Kas boards have some bad units. I have new ones that I am getting ready to install. When I turn this thing on it generates a sound that eventually goes away. Something shorting or ???. I get no response when I press any key. There is a voltage at the key contact 8.5 and that shows up at the YM26600 on the associated pin. That’s all I have to this point. Any suggestions please. Thanks
