08-31-2021, 12:03 AM
I been trying to fix the original stereo decoder in this Sony STR7065. And finally came to the conclusion that the IC was bad.
Now since the IC is not obtainable. I ordered what is suppose to be a MPX decoder for a car radio. I ordered three different ones and got lucky that at least one of them is actually what it was advertised as.
Here is the original circuit.
And here is the block diagram. There was no 38K signal at pin 18. Both the 19k signals were present at the two filter and trap. So at that point I gave up on the original IC.
So the next option is this. It works like charm.
The 8volt regulator is at the top and the two transistors at the bottom right are to switch on the stereo lamp.(not LED) The pot at the right is for tuning the VCO.
The other chip on the little board is a noise blanker that I don't feel like trying to build the filter network for it.
After about a whole day of messing with it. It now looks like this.
Now if I only knew how to use the software to make circuit boards. I will most likely make it by hand.
I will add more here when I get back to it.
Now since the IC is not obtainable. I ordered what is suppose to be a MPX decoder for a car radio. I ordered three different ones and got lucky that at least one of them is actually what it was advertised as.
Here is the original circuit.
And here is the block diagram. There was no 38K signal at pin 18. Both the 19k signals were present at the two filter and trap. So at that point I gave up on the original IC.
So the next option is this. It works like charm.
The 8volt regulator is at the top and the two transistors at the bottom right are to switch on the stereo lamp.(not LED) The pot at the right is for tuning the VCO.
The other chip on the little board is a noise blanker that I don't feel like trying to build the filter network for it.
After about a whole day of messing with it. It now looks like this.
Now if I only knew how to use the software to make circuit boards. I will most likely make it by hand.
I will add more here when I get back to it.
!!!!!!!!!!!!!!!!!!!RESISTANCE IS FUTILE!!!!!!!!!!!!!!!!!!!!!!
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[Image: http://philcoradio.com/phorum/images/smi...on_eek.gif] Chris