Wanted Power Supply For C64C...

[asm1]

Hi

I've just taken delivery of a C64C. I have no Idea if it works and no means of testing it as there was no PSU. So I guess I am after a PSU for a C64 of some sort, preferably with a UK 3 pin plug on it . I think I have read (odd ) that the C64c is compatible PSU wise with the older "Breadbox" C64.... and indeed with the C128 PSU with a bit of hacking.

I know nothing about the C64 so any tips/pointers would be much appreciated.

Andrew

[jvdbossc]

Lucky you, you bought, the best sold, and best system ever! You will not need to look for memory upgrades to

I can't help you, we are to fare away, shipping, and power plug would be killing the transaction.

If you mange to find the connector at the C64 side you can testdrive the C64 with a pc power supply, but then you loose sound, because the original psu has 9V ac to. Once attempted a battery operated one, this was the only consequence.

The C128 psu delivers the right voltages, be sure that it is a 128 psu The amiga 500 psu looks exactly the same but delivers different voltage, you still need to find the right connector etc..

Would not bother, have one orignal bought locally.

---------- Post added at 23:31 ---------- Previous post was at 23:03 ----------

rember that it powered the sid chip and that you could hard wire it to at some points on the motherboard after a small transformer, but why bother..

[asm1]

jvdbossc

Thanks for the info.... I shall bear it in mind.

I didn't buy the C64 I just had to agree to give it a home



Any UK Amibayers out there with C64 PSU's ? or rather



Cheers

[rkauer]

If you fell brave, it is dead easy to make your own C= 64 PSU:

Buy a 9Volts - 2Amperes AC transformer and a plastic case, some 5x wire, a 7-pin DIN connector (best luck finding one!), plus a small 1 Ampere rectifier, a 1000uF capacitor with at least 25V of voltage tolerance and a 7805 with heatsink.

Hook all together and you'll made your own C= supply.

[xc8]

Originally Posted by rkauer

....a 7-pin DIN connector (best luck finding one!)...

how many 7pin din do you want?

http://tinyurl.com/ycokhtz

chris

[Zetr0]

Wow, I was asked this very question this morning!!!

anyway, lets mix up that recipe =D


You can easly get 9vdc from an ATX psu with just a small modification

- It is actually a lot simpler than it sounds, all you need to know is

1. what voltages you need
2. what voltages you have (from the ATX psu)
2. what amps you need the new voltages to be in

As you may know for the most part an ATX psu will provide everything but a +/- 9volt rail so you would have to make one.

Firstly my hats off to my good friend Rkauer whom just showed you (and me) how to over-load a 5volt regulator to get +9volts... awesome!!!


Anyway a little safer (for the component lol) is that some clever people already have and provided it in a nice little 9v regulator package - the 78s09


So hows it work?

well lets take a look at the nice sturdy component "78s09" : it can output 9volts @ 2amps from an input between 12 volts and 35 volts

Although you could run this inline its best to have some protection a small circuit if you will - something like a 78s09 is realistically is only half the solution.

We need to create a small circuit for the device to provide a good steady 9volts of juice



how much current do we need?

we need to know the required amp input to our output and our output needs to be slightly higher that the required input -

According to the HwB the C64 PSU provides 2 rails of 9volts each with 1.0amps


The 78s09 can provide upto 2amps, however since they are relatively cheap it would be prudent to use two of these to provide two independent clean 9v power over two rails say from one source of +12volts. (dont worry about the source most ATX psu's will thump out more than 10amps on the +12volt rail)


Bulding a small circuit -

Using a 78s09 regulator only requires and Source voltage as its output is static (*as long as you are within the voltage range of the device*) however, doing this directly -in-line- makes a bit of noise (electrically speaking), so for the wont of a few pennies I would suggest a small level of filtering

you would need 1 diode, 3 capacitors and 2 regulators

2x 78s09 ------- 12v-35v input 9 volt regulator
1x 1N5400 ------ stop reverse polarity
1x 220u [C1] --- clean (smooth) 12v DC in
2x 47u [C2] ---- clean (smooth) 9v DC out

The Diode provides protection from reverse polarity where as the capacitor of [C1] provides (input stage smoothing) into the regulator, the capacitor [C2] provides (output stage smoothing)

I will say that knowing what your doing with the 9volts out is important, in this example circuit the output filter [C2] is fine as long as its not going directly to another Intergrated Circuit, if it was then I would change [C2] to 100nf to make the voltage as ripple free practically possible.



Lets start with a Schematic

I have knocked up a schematic (for my friend GazCBM) and I have checked it online, the schematic provides 2 rails of 9volts with a maximum of 2 amps each rail.



So, where can you get these components -

Unfortunately maplin sux the big one here and dont have any fixed 9v regulators so with a little bit of hunting I found a place to fill a shopping list - via www.conrad-uk.com


9v Fixed Regulator "78s09"

£0.84p each


1N5400 Diode

1N5400 Diode £0.25 pence each


Capacitors

220uf (16volt Electrolytic Radial) £0.41 pence each


47uF (16volt Electrolytic Radial) £0.30 pence each



There that lot you can net for about £5 from Conrad-uk.com, not sure what the postage is mind, but I doubt it would be that much, the good news is that its all in one place =)

Combine that with what XC8 found (7pin DIN's) and you sir... are away =D

I will say that it might be an idea to Rob a heatsink from a dead psu for the regulators, should that both be at full tilt (although very unlikely) that would be 20watts of heat each that would need a hand dissapaiting - so when laying out your circuit, either include a HUGE ground plane for the regulators to screew to, or a heatsink.

WIth a bit of jiggery and for-thought you should be able to fit this inside an ATX PSU chassis as well..

although... a small micro-atx or pico-psu mod would be awesome too =D


food for thought indeed.... how wierd to be confonrted with the same problem in the same day after posting a solution...... freaky...

[edit]
Please note that the C64 requires 9Volts AC (9VAC) this requires a little more circuitry and a small bit of protoboard - schematic comming soon =D

[xc8]

@asm1

also, you can register on the forum of the Commodore Computer Club (UK) http://commodorecomputerclub.co.uk/ and ask there.

Chris

[Zetr0]

Okay guys

I may a bit of a boo-boo here, I mis-read the 9VAC requirement of the CBM64 as 9VDC, as the CIA timer chips need a phase to work correctly you will need to add a clock source to the current changing it from DC to AC, its not hard but it will require a little more than a 78s09 lol...

heres a great place to start

http://www.ide64.org/stuff.html

and you will be making somthing like this



its not hard and the components are easly sourcable, just need some nerve and a bit of bread board... also a multi-meter... you will certainly need one of them sir!

[xc8]

check this too:

http://twitpic.com/1286wg

and the schematic from Ray Carlsen's site:

http://personalpages.tds.net/~rcarlsen/images/c64ps.jpg

[rkauer]

Originally Posted by Zetr0

Firstly my hats off to my good friend Rkauer whom just showed you (and me) how to over-load a 5volt regulator to get +9volts... awesome!!!

Premature something, my friend?

I didn't noticed the little c=64 used that much current on the 5V rail! Can someone tell me if the real computer needs more than 2A?

Using a simple secondary 9V AC transformer with enough current (3A) to supply the computer can be more than enough:

Using a 78S05, a suitable rectifier and a pair of capacitors will suffice. Take those from Zetr0's recipe.

Take the 9V AC from before the rectifier and do the 5V "magic" after it. Problem solved with a smaller circuit.