[XCSSA] XCSSA (Blowing Fuses and Unsure Why)

[X-otic Computer Systems of San Antonio]

Bottom Posting Engaged!

On Jan 11, 2009, at 9:37 PM, X-otic Computer Systems of San Antonio  
wrote:

> On Sunday 11 January 2009 06:42:27 pm X-otic Computer Systems of San  
> Antonio
> wrote:
>> Didn't realize you were building this on perf-board, thought you  
>> had an
>> etched PWB, now I understand why you've had troubles.
>>
>> Perf-boards are handy, but dangerous because most component leads  
>> do not
>> fit tightly in the holes, and the leads can, and do flex (hello short
>> circuit). And
>> yes, I learned this lesson too.
>
> There's also issues with the size of the wires (don't recommend  
> building a
> power supply using wire wrap!).. Especially with the ground paths,  
> which need
> to be fat and wide.. See how power traces are larger on PCBs?
> 	http://www.sampson-jeff.com/motor/motor_b.gif
>

I'm using some reasonably gauged wire on a spool I picked up from  
Radio Shack. The label fell off so I don't know the exact gauge  
though, but it's definitely heftier than wire-wrap. I also have a  
busted PSU I'm using the wires from for the really big stuff (I'm  
going to use this wire for connecting everything together via Molex  
connectors). I'll be honest, though, for some of the connections, I  
just re-used the cut-off legs from a soldered component :)

I'm not expecting my current design to power a full loaded synth,  
though. As soon as I settle on a design, the very next step is going  
to be ordering a board from BatchPCB :) For that, I'm using the bottom  
of the board as a ground. Haven't gotten far enough to know if that's  
a good idea or not for power. That suggestion was made for my last  
power board (that used the C64 PSU) and my board to hold EEPROM chips.  
I'm also using the biggest traces I can possibly fit onto it so I'm  
hoping we should be good.

I'm not 100% sure if I'm going to keep with my center-tapped design,  
though. Half of it is being fully rectified, and the other half is  
just off the center tap (sharing the GND from the - of the rectifier).  
This seems to work, but it means I need more capacitance on the +5V.  
Not a big deal, but I'm wondering if I'm over-complicating it a bit. I  
could just take the 9VAC and regulate that down to 9VDC and 5VDC. I  
don't really like that, though, because that's alot of heat to expel  
to get it 9VAC down to 5VDC and most of the drain will be on the 5VDC  
rail.

Oh well, at least I've got stuff to think about :)

Tim