Surf PI 1.2 problems

[Qiaozhi]

Qiaozhi I'm using PCB board from silverdog

I have a blank Surf-PI Longboard from Silverdog (marked SURF 1.2 "ApB"), and ICs U4 and U7 are definitely connected to the -5V supply (U6 pin 5). That is ..... as long as you remember to put in the wire link that is located between R8 and U2 on the PCB. If you do not have continuity between U4 pin 7 and U6 pin 5, then you've either not inserted the wire link, or there's a break in the track somewhere

Note 2 in the datasheet just refers to the conditions under which the tests were carried out. This is not a restriction.

[localbug]

Why delay configuration failed/didn't work

4093 NAND gate schmitt trigger

input1 input2 output
+ + -
+ - +
- + +
- - +

[Qiaozhi]

Why delay configuration failed/didn't work

4093 NAND gate schmitt trigger

input1 input2 output
+ + -
+ - +
- + +
- - +

Are you saying that you've found the fault in your Surf-PI?

[localbug]

Are you saying that you've found the fault in your Surf-PI?

Yes, if I am the only one having this problem.

No, because I found 4093 wrongly configured on the schematic and PCB.

4093 truth table

input1 input2 output
Positive Positive Negative
Positive Negative Positive
Negative Positive Positive
Negative Negative Positive

[Qiaozhi]

Yes, if I am the only one having this problem.

No, because I found 4093 wrongly configured on the schematic and PCB.

4093 truth table

input1 input2 output
Positive Positive Negative
Positive Negative Positive
Negative Positive Positive
Negative Negative Positive

There is no fault with the Surf-PI schematic. Many members have successfully built this detector, and the schematic you're referring to is an original from White's Electronics.

Did you check (as I suggested earlier) that you have +/-5V on IC4 and IC7?

[localbug]

U4 pin7 -4.7v , pin14 5v
U7 pin7 -4.7v , pin14 5v