C64 Optimized PSU Without LED?

[m00dawg]

So I am trying to build the C64 PSU on a simple protoboard (I only used a small section for the BankSticks so I figure, why not?). I have a few questions however:

1. Has someone already made a board for this and might I have the EageCAD? I saw a triangular board but was looking for a square and, while I'm learning EagleCAD, I don't have enough skills to make a square one :)

2. If I have to use the protoboard, no biggie, but I was going to forgo the LED. I figure I can tell it's own simply by the LCD panel and other LEDs I'll eventually have. So, if I remove the LED, I assume I don't need the diodes from the power switch? And, I assume the reason there isn't a connection on the diagram for the VS on J1 is because it is already grounded from VS on J2?

Also, and this might be a bit newb, but how does the power switch work? I noticed that there is two sections for the switch and I'm not sure what switch to get, nor how to wire it.

Thanks All!

Tim

[seppoman]

2. If I have to use the protoboard, no biggie, but I was going to forgo the LED. I figure I can tell it's own simply by the LCD panel and other LEDs I'll eventually have. So, if I remove the LED, I assume I don't need the diodes from the power switch?

what diodes do you mean? The rectifier (X1 in the optimized diagram) will still be necessary. But it's no problem to leave the LED out (and of course, the corresponding 220 Ohm resistor).

And, I assume the reason there isn't a connection on the diagram for the VS on J1 is because it is already grounded from VS on J2?

exactly. having only one ground connection prevents ground loops (hum).

Also, and this might be a bit newb, but how does the power switch work? I noticed that there is two sections for the switch and I'm not sure what switch to get, nor how to wire it.

You need a dual power switch that opens/closes two cirquits at once.

S

[m00dawg]

what diodes do you mean? The rectifier (X1 in the optimized diagram) will still be necessary. But it's no problem to leave the LED out (and of course, the corresponding 220 Ohm resistor).

Ah I thought those were separate diodes. Now I get it :) On that note, however, I was unable to find that exact model with my distributor (Allied Electronics). I am guessing that I can get a higher rated rectifier (say 600V, 50A or something), just not a lower one in this case?

[seppoman]

On that note, however, I was unable to find that exact model with my distributor (Allied Electronics). I am guessing that I can get a higher rated rectifier (say 600V, 50A or something), just not a lower one in this case?

yes, higher rating is always ok - but a 50A version would be huge. Rectifiers are very common parts, you should easily find compact parts with e.g. 40 or 80V, 1A, 1.5A etc. so no need to pull out the really big tools :)

S

[m00dawg]

That you very much! You have been most helpful!

[stryd_one]

Multi-word, all uppercase, prefixed with spaces, not relevant to the thread  tags have been removed. :P

[m00dawg]

My apologies. I was only trying to help as I was not able to find the original answer to my question via the forums (and I thought having good tags would help solve such problems in the future). Is there a standards or suggested tags page I can reference? If not, there should be as the tagging process is not clear. All points you mention in your comment are points that, I thought, were actually valid :)

[stryd_one]

Heh, don't be sorry man! there's no "rules" as such, but some things just don't link up right, and some things seemed to become a habit pretty quickly. just add in whatever you think works and if i see a problem I'll zap em, and let you know if I'm unsure of what to replace them with :) (generally if I can, I just fix them)

Lower case is definitely the go, and the leading space makes them not work, and you don't need a "SID" tag because it's in the SID forum (and not about SIDs which is really just the chip).

There's a "psu" tag in use already (using existing tags is the way to go!). Maybe "rectifier" too... because this does come up quite often. It seems it's hard to find, perhaps because of the misleading symbol that looks just like 4 diodes, people search the wrong term? Whatever it is, hopefully the tags will help the next guy :)

Tag away, m00ny! :D

[m00dawg]

Thanks for the clarification! I'll try to be more reserved, proper, and critical about these sorts of things :)

[m00dawg]

Oh boy...so while we're here I find myself confused with this whole ground loop issue. Using the C64 Optimized PSU, how exactly do I connect the additional modules to avoid ground loops?

My original idea was to use 2-pin SIL headers for each module on the PSU board. That way, I can run a cable to each module directly. The idea was so I can move things around if need be, and I can expand more modules as needed (since I only have 1 SID / 1 CORE at the moment). Yes, I will end up with a lot of pin headers, but I figure that makes things easy to expand.

After asking around work, I was told I should NOT do that and should, instead, make runs to each module (so say from PSU -> CORE1 -> CORE2). I was thinking of accomplishing that was with a single ribbon cable with periodic connections for each module type (ie one cable for COREs and one for SIDs).

I thought about posting this in this thread but that thread seems to have died sometime ago and I haven't really seen a great answer to this.

Thanks again!

Tim

[stryd_one]

run a cable to each module directly.

After asking around work, I was told I should NOT do that

Did you ask Why?

[m00dawg]

Did you ask Why?

Yep. They said ground loops would be possible and/or that it would potentially create more noise. From what I've read, it seems like my design fit the bill for star grounding if I hooked up the headers correctly (I am guessing I would hook each up to the ground point individually? The whole process is surprisingly complicated, or perhaps that is just me being confused :)

How does one create a ground loop anyway?

[stryd_one]

How does one create a ground loop anyway?

Give the signal >1 path to ground

[m00dawg]

So that means, then, that, as long as the modules link back to the same ground point, I can hook it up however I want? I'm sure I am showing my newb colors but, man, it's had me confused for a few days now :)

[stryd_one]

So that means, then, that, as long as the modules link back to the same ground point, I can hook it up however I want?

So long as there's only one such link to ground.

[nILS]

An example of Ground Loop vs. No Ground Loop can be found in the attached picture. Notice that the wiring is rather random and neither complete nor necessarily correct. It's just there to illustrate how to (not) wire your ground connections.

[stryd_one]

Ahh thanks nils! That's a really simple and easy representation (I think...does it make sense to everyone else?)

I think that needs to be wikified too.

[m00dawg]

+1 for wikification! That really does help! I think I will have to do some experimenting either way but I think I have a good idea about what (or rather what NOT) to do when I wire this thing together. Thanks for everyone's help!