BOM and questions

[hsnewman]

Let me prefix this by saying I don't understand alot about electronic parts, specifically the specifications of each part and how to identify the proper part to buy. That said, I am capable of building electronic kits.

I have a Klyball Superboard II bare board, but now want to populate it. I downloaded the BOM.zip from this site but ordering the components such as capacitors and the like is very hard due to the many types of those devices that may have the same specs. Moreover, the BOM doesn't contain all the parameters that Digikey for example specify about each part.

I also found the Superboard II assembly guide, and in it there are specifications for each part, but it again doesn't give all the details about, for example, what type of capacitor to use.

I've begun creating a BOM from that guide, and it resides here: https://docs.google.com/spreadsheets/d/ ... sp=sharing

My question is how do I determine what parts to buy given the information provided? Example:
C-102 is a .001 µF capacitor. Searching for .001µF capacitor on digi-key results in three types: aluminum electrolytic, ceramic, and film capacitors, with different voltages, and specs. How can I possibly order all of those parts when there are so many variations and types?

Does anyone have a Digi-Key list which has all the parts i will need for the Superboard II build?

Thanks!

[Mark]

A good overview on capacitor types can be found here: https://www.jameco.com/Jameco/workshop/ ... -caps.html
And their use can be summarized as a picture:

capacitors.jpg (416.65 KiB) Viewed 1883 times

Fortunately for the 600 build, most capacitors are not critical. The voltages you are dealing with are mostly +5v. It's best not to run capacitors at or near their rated voltages! Generally as voltages increase, capacitor size increases. For 5v operation, pick something rated for at least 10V or 16V or something that has a good price & size for your application. If a small value capacitor is only available as a 100V part, that is OK as long as the capacitance is correct. You don't need a 100V capacitor, it just happens to be the rated voltage of the capacitor with the capacitance you need.

Typically for bypass capacitors used for noise suppression near chips power supply lines, ceramic .1uf capacitors are used. They are cheap and are usually rated at 50v or so, which is way overkill (you only need 10v), they hold up well to abuse. As you can see in the picture above, you could replace these with other types of capacitors and not notice a difference in operation. Ceramic caps can vary in capacitance by 10% to 20%, this doesn't cause problems with noise filtering at all but it is more of a concern in oscillator circuits. You don't want the frequency changing as the temperature changes. You could use metal film caps, if you like the look better, or find some green ceramics to match the original OSI boards.

I believe OSI tended to use silver mica caps for the baud rate generators, clock circuits, and filters. These types of caps have very good temperature stability and are very precise. But generally any non-polarized cap with a 5% to 10% tolerance will work. See the C1P service manual page 5 or so for a detailed list of parts and values.

Finally for larger capacitor values (1uf-5000uf+), aluminum electrolytic capacitors are used. These are usually polarized capacitors (there is a + and - side) and are mainly used for power supply filtering in OSI. Do NOT hook them up backwards! Pick the axial or radial form factor with the size & values you need. No need to get super small high density caps for this 1980's design!

So overall, any choice you make will work as long at the capacitance is close, physical size fits and rated voltage is higher than your circuit.

Good Luck!

[hsnewman]

That's great info, thanks. "See the C1P service manual page 5 or so for a detailed list of parts and values." is exactly what I needed!

Harris