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I have a vox board PB1438B and another one that does not have a PB number on it.
The B model has a sn72560 IC and mc14013 IC ..
The one with no part number has mc14024 and mc14011 Where can I find a schematic for this one with no part number.?
Attached is a photo of the board that has no part number. Its malfunction is that it will not key into transmit in cw. no break-in.
Robert

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I found the microscopic part number and it is a PB1685
This board was in a FT301S. . any schematics for this one??
relay control is provided by a quad 2 input nand gate which drives a npn transistor and in turn switches another? npn transistor on which then activates the relay. I had to sub out the 2sc372 and 2sc735 with 2n2222a. it worked for a while then quit, so I am getting some where. Now, it hangs in tx. I will undo what I did and check the output of the gate.

Hello Robert.

I just uploaded a Japanese version of the 301/S. The echematics & diagrams show very early models. This one also shows the analog LED indicator schematic for non-D models which is not present? in more recent D model manuals.

Hope this helps, it helped me with one of my 301S units.

Jim

The output of the IC is ok. The problem is with the two switching transistors.
I dont know why they are using 2 NPN transistors to switch the relay !!
There is a diode between them. I dont like the way they did it. I tried 2 2n2222.

I had to re-arrange the leads. now, when I key, it hangs !!? They are just switches so it should be simple.
since I have to work with what I have here, I will try a 2n2222 (NPN) and drive a 2n2907 (PNP). That should do it, I hope.
I am working on two ft301 at the same time. :))?
Robert KH2BR

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Problem solved
I have the vox board working now. I changed the circuit a little. Now, the MC14011 drives a 2n2222 which in turn drives a mosfet, 2n7000.
It works very well now. Q606 is a 2n2222 and Q607 is a 2n7000.. the diode d602 was eliminated. We will see