keen wrote:Hello franzkleid,
I had same problem on 4th batch kit.
Please try unbuffered 4011UB.
I solved R151 problem by it.
cheers
wow is that really the issue? My local electronics retailers don't seem to differentiate, just listing "4011" without any suffix. I guess I could go in-person or call to verify the buffered vs unbuffered versions...
EDIT: I just checked the TR-808 service manual and as far as I can tell they used 4011
B type NAND gates. So maybe that's not the problem?
Attached screenshot from the service manual:

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