AIN bypass caps on SmashTV MBHP_AIN_R2

[drin]

Hi all. I'm assembling all the great SmashTV kits I purchased (hi Tim!) and noticed that the AIN kit comes with 4 caps. I believe these are the bypass caps that Thorsten describes putting between Vss and ground on each 4051. However, being a dunce I'm not sure which pins these are!

I've searched for '4051 datasheet' hoping to find a pinout but there appear to be quite a few 4051 analog multiplexer chip varieties out there, to my dismay.

Can anyone help out? Do I tie the caps to a common ground on the board? To Vs on J5? I'm lost... :(

Thanks!

-drin

[illogik]

hi,

I've searched for '4051 datasheet' hoping to find a pinout but there appear to be quite a few 4051 analog multiplexer chip varieties out there, to my dismay.

but they probably all have the same pinout, just different manufacturers.

and look at the AIN module page, the pictures below show the right spot!

cheers, marcel

[ImAlive]

Yeah, most commonly it's just diagonally between the topmost left and the lowest right pin (top view). You can also buy sockets in which these bypass caps are already contained. And as illogik posted, there are pics on the module page. (If I may add this, soldering stuff on the bottom side of the board sucks ;D )

[drin]

hi,

but they probably all have the same pinout, just different manufacturers.

and look at the AIN module page, the pictures below show the right spot!

Thanks Marcel, but TK's PCB layout and Smash's layout are different! The R2 Smash board has been heavily redesigned to eliminate a number of jumpers and the layout really doesn't resemble TK's board any more. I've already tried saving the image from the AIN page and enlarging it to see the connections - can't make them match.

Thanks!

-drin

[drin]

Yeah, most commonly it's just diagonally between the topmost left and the lowest right pin (top view). You can also buy sockets in which these bypass caps are already contained. And as illogik posted, there are pics on the module page. (If I may add this, soldering stuff on the bottom side of the board sucks ;D )

Thanks! I tried the pics but didn't get anywhere since the board layouts are different. I'll take your word on the pin connections and give it a try. :)

Thanks again!

-drin

[ImAlive]

Oops, I was wrong wrong wrong!! (Damn memory...) The caps go between pin 16 and one out of 6,7 or 8! So that would be the topmost RIGHT and lowest LEFT pins, viewed from the top. Here's an image, as viewed from the solder side:

[Screaming_Rabbit]

Tip:

To prevent contact of the bare wire with the PCB traces, don't place the caps like on the picture. Cut one leg so the cap body is right at the IC-pin (for example: Pin 16) then put a shrink tube over the other leg and solder it to the other pin (Pin 6, 7 or 8).

Greets, Roger

[drin]

Oops, I was wrong wrong wrong!! (Damn memory...) The caps go between pin 16 and one out of 6,7 or 8! So that would be the topmost RIGHT and lowest LEFT pins, viewed from the top. Here's an image, as viewed from the solder side:

<image redacted>

Much to my surprise I was able to figure out that your initial advice was a little reversed! Thanks! :)

Thanks to all who responded. I'll be installing the caps this afternoon.

-drin

[drin]

Tip:

To prevent contact of the bare wire with the PCB traces, don't place the caps like on the picture. Cut one leg so the cap body is right at the IC-pin (for example: Pin 16) then put a shrink tube over the other leg and solder it to the other pin (Pin 6, 7 or 8).

Greets, Roger

Thanks Roger! I'll make sure and do that.

-drin