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Gb: F4 pcb

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#44
Last time I checked the F3 service manual, the psu was schem was wrong. You need to stack the rails so that -23 becomes ground and then you'll have +46 on V+ (in reference to gnd). You will probably still be able to make the switch system, but you need to do a lot of thinking. 😉
 
#45
Single-Ended PSU

cviller said:
Last time I checked the F3 service manual, the psu was schem was wrong. You need to stack the rails so that -23 becomes ground and then you'll have +46 on V+ (in reference to gnd). You will probably still be able to make the switch system, but you need to do a lot of thinking. 😉
Click to expand...

Is this what I need to change, a complementary to a single-ended supply for the F3?

Single-ended and differential amplifiers : OPERATIONAL AMPLIFIERS

Is there a correct single-ended schematic for the F3 to look at?
 
#46
No, this link is about signals and not psu. I think you should focus on getting one amp to work first and when that is done, then it will be much more clear for you what you need to do to make it switchable. You can use slightly longer wires to hook it up so that you can just cut them when you are ready to add more stuff.

Regarding the schem, I don't have one, but perhaps you can find one in the F3 thread. Otherwise it would be a good exercise for you to draw it yourself - post or mail it to me and I'll check if it will work. I don't know what caps, resistors and bridges you are planning on using, so I can't draw it for you.
 
#47
cviller said:
No, this link is about signals and not psu. I think you should focus on getting one amp to work first and when that is done, then it will be much more clear for you what you need to do to make it switchable. You can use slightly longer wires to hook it up so that you can just cut them when you are ready to add more stuff.

Regarding the schem, I don't have one, but perhaps you can find one in the F3 thread. Otherwise it would be a good exercise for you to draw it yourself - post or mail it to me and I'll check if it will work. I don't know what caps, resistors and bridges you are planning on using, so I can't draw it for you.
Click to expand...

Thanks for your help. I'll do just that.
 
#48
I have some bad news regarding the F4 boards you have ordered. I ran over them again today and to my horror I discovered an error in the layout. 🙁
Good news is that it is fixable.

R6 should be connected to the node between P2 and C4 instead of as it is now between P2 and R22. The mistake can be fixed relatively easily by cutting two traces and extending the leg of R22 to connect to the other end of P2 and bending one leg on P2. I have attached a drawing of what needs to be done to fix the problem.

I have already written to those who have ordered, so if you have ordered, but not received the mail, please write to me.

I still have more boards left and I'll cut the traces so that the boards can be used virtually without any extra effort. However since people might not like to have to stretch a leg on a resistor, I'll lower the price from $9 to $7.
 

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  • f4_v1_trace_fix.JPG
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#52
Fixing the layout error

Before sending the boards I cut the traces so that all you need to do is to bend one leg on R22 and one on P2 to get the correct operation. Here is a picture of how the boards look after I have cut the two traces.
 

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  • f4_trace_cut.JPG
    f4_trace_cut.JPG
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#54
Hi,
I received the F-4 boards (As well as the rectifier boards) in good condition, Thank you!
I have a question: what is the best tool too use to cut the traces on the PCB?
Regards,
Eric
 
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