Decoupling Capacitors for memory chips on motherboard

[rockdoc2010]

Hello there,

 

I am building a 1200Xl from scratch. On the motherboard there are what appear to be decoupling capacitors that are located between pin 8 and pin 16 on the memory chip. C16 - C23

 

I am wanting to install gold plated machine pin sockets that come with a decoupling capacitor installed in the frame of the socket.

 

The Atari schematic calls out 0.1uF on the motherboard.

The Capactor in the frame is also 0.1uF

That would give 0.2uF per memory chip if I installed the caps in the board.

 

Do I just replace the caps on the MB with wire, omit them entirely or leave the caps in the motherboard?

 

Thank You

 

Douglasmemdetail.bmp

[+5-11under]

Don't add a wire. That will make a short between V+ and GND.

Two choices: Don't install the capacitors on the MB (0.1 uF result), or install the capacitors on the MB (0.2 uF result). Either is fine. I'd probably do the 2nd.

 

Edit: also verify that the last pin on either side of the DIP package is okay to have that capacitor. There may be cases where those two pins are not voltage inputs.

Edited February 1, 2014 by 5-11under

[1050]

Use both caps, if you'll go to the Atmel website and do some looking thru their application notes you'll find one where they universally recommend upping the standard .1 uf ceramic to .22 uf ceramic across the board for decoupling caps. So it's really a non-issue? Do what you want.

[Brian of Fairfield]

Hi Douglas, nice socket + capacitor thing.  Where did you get them from please?

Thanks, Brian