I’ve finally managed to knock together a working PSU from the Optimised PSU diagram, and using the original C64 power socket and switch. I did it on stripboard, and it looks terrible, and I’m sure the layout is incredibly inefficient, space-wise, but the voltages check out
5.13V and
13.88V
It’s a minor right of passage for me, as it’s the 1st actual circuit I’ve created from a circuit diagram. I’m surprised it works!
The only problem is, I fell at the first hurdle when it came to connecting the PSU to the MB Core. Desoldering the voltage regulator from my Smash TV PCB, the pad nearest the big cap came away from the board. I tried putting a jumper across the holes where pins 1 and 3 of the 7805 had been, but I don’t think there was enough pad there to make a connection.
Two questions:
Am I jumpering across the right holes anyway where the 7805 used to be?
Where should the 5V output from the PSU be connected to the Smash TV Core board. The Optimised PSU diagram says J2, but J1 on the Smash TV board is the 5V OUTPUT. Should I just connect the PSU to the J1 power input pins on the Smash TV board?
I know this is incredibly basic stuff, but any help would be much appreciated.
Am I jumpering across the right holes anyway where the 7805 used to be?
you should be jumpering accross the outside pins of where the 7805 use to be, the center pin is ground. The reason for this is that way you keep the caps in the circuit (the rectifier can go though) which help smooth out the DC voltage. If you pulled the pad out, scrape away some of the soldermask from the trace right next to the where the pad was and solder to that. Check continuity with a volt meter if your not sure its connected.
Where should the 5V output from the PSU be connected to the Smash TV Core board. The Optimised PSU diagram says J2, but J1 on the Smash TV board is the 5V OUTPUT. Should I just connect the PSU to the J1 power input pins on the Smash TV board?
Either one if the rectifier is still there. If you take it off, then J2
Hello toneburst! I have recently completed my Optimized(not sure if I spelled that correctly) PSU board too and as you were, I was pretty excited to see it working as well!
As for the correct jumper to connect to, If you look at the page dedicated to the Core board, http://ucapps.de/mbhp_core.html here you will find a section describing the functions of all the jumpers on the Core module. It explains everything you will need to know about using J1 or J2 as the 5v input just as altitude explained. It helped me a lot and maybe it can give you some insight as well?
I was a bit confused as to whether J1 and J2 on the Core boards on this site actually matched the ones on the SmashTV boards, since they look quite different.
I’ll try soldering to the trace and test it to see if that works. It’s gonna look messy, but hopefully it will work.
I’ll post a pic of the PSU board when I’ve finished it (just need to add some SIL headers and the resistor for the LED).
Even though your psu is ugly (you said it, not me), do you think it would be possible for you to post a picture of the front and the back. Because im having terrible problems with my psu, and perhaps it would help me to decifer your pics.
Hey Carsten, I took a few pics of my PSU board for you to check out. These pics were taken with my motorola RAZR mobile phone so don’t expect too much from them…
Some of you may notice that there are quite a few more jumper pins on my board than the original schematic drawing has. I’ll explain…
In the top pic there is a row of 4 SIL pins on the bottom left(kinda difficult to see) of the board. This is where my 7pin DIN plug for the C64 PSU and the on/off switch connect to by means of a female connector w/crimp pins. The 8pin DIL jumper on the bottom right is where the Core and SID boards will get their 5v from individually(not chained from board to board as on the original schematic). The next 3pin SIL jumper up from that one is for the C64 power indicator LED. And the last 4pin SIL jumper in the top right is where I will send out the 14v to the SID modules individually as described before.
I’m not sure if any of this will help you or not Carsten, but I dunno?
Let me know what you guys think of my PSU board too… ;D
Oh crap! :( I just noticed after reading over my last post that I made a mistake on my board. Grrrrr! >:(
On this part:
The 8pin DIL jumper on the bottom right is where the Core and SID boards will get their 5v from individually(not chained from board to board as on the original schematic).
I would have needed to use a 16pin DIL pin header to send 5v to the Core and SID boards individually! Oh well, I guess I can still fix it…
By the way, Does anyone see a problem in not chaining them as in the Optimized PSU schematic and sending each one out separately anyway? It seemed like a good idea to me.
By the way, Does anyone see a problem in not chaining them as in the Optimized PSU schematic and sending each one out separately anyway? It seemed like a good idea to me.
You are supposed to put a cap on the end of the chain to cut down on the digital noise
You are supposed to put a cap on the end of the chain to cut down on the digital noise
Yeah, I was planning on putting it in later on when I make up all of my wires with their connectors and such. I didn’t give that part enough thought It seems. I guess it might not work the same with the 5v going out separately to each board huh?
Yeah, I was planning on putting it in later on when I make up all of my wires with their connectors and such. I didn’t give that part enough thought It seems. I guess it might not work the same with the 5v going out separately to each board huh?
-tel3
it would work, but you’d have to place a cap at the end of each length of wire. if you have enough caps i guess that might be ok. the only possible problem i can see with doing it that way, is that each cap has to ‘fill up’ with charge when you turn it on, and the resulting current draw may be too high for the 7805.
it would work, but you’d have to place a cap at the end of each length of wire. if you have enough caps i guess that might be ok.
Yeah, I thought that might be what I would have to do…
the only possible problem i can see with doing it that way, is that each cap has to ‘fill up’ with charge when you turn it on, and the resulting current draw may be too high for the 7805.
I guess the only thing I can do is to try it? I would think the worst that could happen is the 7805 would get very hot and possibly fry? Or, It just won’t work? ;D
If it comes down to it, I’ll just do it the way TK designed it! I’m just not sure how to chain the modules together while using the crimp pin type connectors I like so much that will only fit one wire in them?? How do some of you guys do it?
Thanks for your help peeps! And sorry for jack’n your thread toneburst!!! (edit:Oops not carsten!)
Incidentally, the hardest thing about making the PSU was actually desoldering the original C64 power socket and switch.
Have you tried desoldering with some desoldering braid? It works pretty good for me. The only thing is you have to be careful about how hot the parts you are trying to desolder get while letting the copper braid “suck up” all of the solder. Definitley worth a try if you haven’t already.
I keep meaning to buy some soldering braid, but keep forgetting to order some.
Having screwed up one of the pads on my Core board, mind you, I’m a bit scared of getting things too hot again. It might be a good solution when it comes to desoldering C64 bits from the board though.
If it comes down to it, I’ll just do it the way TK designed it! I’m just not sure how to chain the modules together while using the crimp pin type connectors I like so much that will only fit one wire in them?? How do some of you guys do it?
Talking of crimp pin connectors- what tool would I use to fit these? Newbie question, I’m afraid, but without knowing the correct terminology, I’m having great difficulty tracking down the right tools (and parts, for that matter).
I’ll explain…
I guess it might not work the same with the 5v going out separately to each board huh?