Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

74HC04 vs SN7404n notice #2

Open
zhblue opened this issue Aug 8, 2021 · 4 comments
Open

74HC04 vs SN7404n notice #2

zhblue opened this issue Aug 8, 2021 · 4 comments

Comments

@zhblue
Copy link

zhblue commented Aug 8, 2021

a second hand IC maked "sn7404n england" works fine with 470 ohm resister
but a brandly new IC maked "74HC04" from JLC market need a 4.7k ohm resister to work with.
i have no idea about why , just post here for people who might need it.

@zhblue
Copy link
Author

zhblue commented Aug 18, 2021

the extra 470 ohm resister can be used parallelly on the outer two pin of volume control, make volume adjust more smooth.

@AidenShaw2020
Copy link

AidenShaw2020 commented Jan 14, 2022

I had same issue, that me get almost crazy, but resolution is pretty quite simple :)
Only what you need is change oscilator circuit from this:
image
, to this:
image

After that, you get perfectly stable frequency +/-1Hz.

@dekkit
Copy link

dekkit commented Mar 13, 2022

Interesting i had a batch of SN7404n (ordered 5) ..4x worked with 470R.

..but 1x pcb needed both 470 replaced with a 4.7k.

I suspect anything above 1k will work more consistently.

Note (new builders):

  • if building the circuit the first time - becareful and pay attention to the dots and chip orientation (as labels written on the pcb arent necessarily orientated the correct way)

@badass-boss
Copy link

These values must still be just downright incorrect. This card doesn't work right at all using all original mouser parts linked in the BOM. 1K resistors paired with a 100pf cap generate a TON of random noise and loud glitches and the FM music gets all corrupted at all times. When changing resistors to a higher value, the issue is fixed and I think this card works best with 4.7k resistors. What are these resistors even supposed to achieve and what is the configuration of the original Adlib card?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

4 participants