1541 won't work with VIC-20

[idrougge]

It was UB4 I replaced. You can buy it here: http://www.elfa.se/elfa/produkter/se/2012856.htm

I replaced the 7406, now the drive is even more irresponsive. Don't know if it's a good sign or not.
I've asked a friend to bring some 6522s and a suitable PSU this weekend, so we'll be able to do some more tests.
I also tested the joystick yesterday, it worked fine in all directions except for right, but that could have been due to the joystick or the joystick port itself, didn't have time to do further tests then.

As for 6522 VIAs, stealing them from a 1541 isn't necessary, since Bejoken (http://www.bejoken.se/) still stocks the Rockwell 1 MHz version.

[Boray]

You replaced UB4 before trying with a 3A PSU? Well I hope it was socketed... The original Vic requires a lot of power. Those big heat sinks should get as hot that you burn yourself if you touch them... At least mine does... I have moved them out of the computer to keep the heat down... And my VIC chip has an extra home made heat sink too...

/Anders

[carlsson]

Yes, the "right" direction requires a data direction register to be altered and reads from yet another register. I wonder about the power consumption, if you only get ~9W instead of 25W, shouldn't the picture be flakey and other problems appear?

[idrougge]

You replaced UB4 before trying with a 3A PSU? Well I hope it was socketed... ;) The original Vic requires a lot of power. Those big heat sinks should get as hot that you burn yourself if you touch them... At least mine does... I have moved them out of the computer to keep the heat down... And my VIC chip has an extra home made heat sink too...

It's socketed now! ;-)
I trust that the ceramic casing does it for the 6561.
I ran the VIC for hours yesterday, peeked and poked, and the only flakiness I could see was some very slight "snow" (if you've used an old CGA PC, you'll know) when drawing characters.

[Boray]

I've never seen any "snow" like that. When thinking of it, in the description of the Vic chip, it says one of the characteristics is that there is NO distortions to the display even when text is outputted... You said earlier that the low-video pin of the video port wasn't connected. Are you sure about that? Maybe it just was so weak because of the PSU so you couldn't see it at all... On mine there is a video signal there, but extrememly weak... Also read this: http://sleepingelephant.com/ipw-web/bul ... .php?t=202

Btw, why are there so many Vic20s out there without a PSU??? Almost every time a Vic20 is out on Tradera, then there is no PSU for it... I've never had any problems with a PSU breaking down so they must just get separated from the vic for some odd reason.... Maybe people store them in separated places and when they find the PSU, they don't recognize it to belong to the VIC20 just because it says VC 20 on it and not VIC-20

And why is it called "Power Supply" in english and not Transformer???

Well, it will be interesting to see if your problems disappears when you try your friend's PSU...

/Anders

[carlsson]

Well, the brown brick quite frequently broke down for me, and we once bought a plastic bag (!) full of replacement PSU:s for use with the newer VIC or C64. These even had a power switch. A year ago I sent the remaining ones away to someone in Linköping (feh, I can't remember who), but they were reported to not work properly.

The small black 9V PSU is yet working, and I hope it will for long. Maybe the introduction of dual voltages and design change made the PSU more "fragile"?

[Boray]

idrougge, Did your friend come so you could test with the original PSU?

/Anders

[carlsson]

I just browsed through ELFA (very big but also rather expensive electronics distributor both to companies and individuals), and power supplies which output AC seems outstandingly few.. or I look in the wrong categories. I have looked both for "transformator", "batterieliminator" and "nätaggregat" of various types.

There is a user forum at ELFA's home page, so it could be fruitful to post a question there about where to find a possible PSU, and then adapt the power connector as required.

On the other hand, I saw that Clas Ohlsson now is selling a DC adapter which outputs 6V/3.5A so in theory I could at least the paper moving in my Casio unit. However, it is a little expensive (295 kr) for something I don't know if it will work.

[Boray]

Good news!!! A 9V DC 3A power supply would work just as well! Here is the words from Ray Carlsen (Commodore repair guru) (plus my question to him):

> Another question... It is very hard to get hold of a substitute
> PSU for the old 2-prong european vic20 (220v AC -> 3A 9v AC.)
> At least two people are looking for one on the "Denial" forum.
> If everything is rectified inside anyway - then would it work
> just as well with a PSU that generates 3A 9v DC???

Anders,
After looking over the schematic, I believe it would work fine
with a DC supply. All DC sources derived from that AC power pack are
indeed rectified and used as either 9VDC (cassette motor) or 5VDC
(everything else). The only other place the 9VAC shows up is at the user
port. Unless something is plugged in there that needs the AC source, it
shouldn't matter that it's missing.
I don't like to give out information when I've not tried it
myself, but in this case, I don't have a problem with it. Note the
polarity of the DC supply source would not matter because of the bridge
rectifier in the computer. Whichever way you connect a DC input, the
rectifiers would reverse it if necessary.
Lastly, I've never tried to buy a 9 VDC 3 Amp adaptor, but it
seems to me that would be as rare as a 9VAC power pack. If I couldn't
find one, I'd probably buy a 9 volt transformer and install it in a
metal case to power my VIC. Even so, a three Amp would be unusual.

Ray

On page 70 of Clas Ohlson's latest catalog, you will find one (or 3) suitable transformer(s). (Article number 32-8529) for 295 swedish crowns.

/Anders

[Leeeeee]

Good news!!! A 9V DC 3A power supply would work just as well!

It won't, 9VAC will need to be replaced by a 12V DC (RMS VAC * root 2).

Lee.

[carlsson]

I posted a question on ELFA user forums, and one replied me personally with his friend owned a VIC-20 and was certain it took 9VDC input. As we all know, it quite doesn't. Personally I'm too uneducated (or stupid?) to understand why a direct current would work the same was as an alternating, but if it does...

Someone else told me to look among transformers. I'm sure one can build your own PSU which delivers the right power - maybe even one with two connectors that delivers both 5V and 9V 3A. If I'm not mistaken, it doesn't do any harm if the PSU is able to deliver more current than the computer drains, only the opposite.

[Boray]

12V??? Can you explain that a little better? So that a novice like me would understand?

I actually thought that it would be the other way around if any difference... The sinuswave rectified would be as a lot of upward bows going from 0 to 9V at top right? And 9V DC would constantly be a top of 9V. So as a total, 9V DC would be more than a 9V AC????

/Anders

[Boray]

Anyway, here is a little more info from Ray Carlsen

> There is a "battery eliminator" that can deliver
> 9V/3A DC sold by a company here in Sweden (called "Clas Ohlson").

Anders,
I have to wonder what kind of equipment takes that voltage and
current. Battery eliminators here are usually 12V... to run a car radio
for example.

> They also have one that can deliver 9V/4A and one for 9V/6A.
> I guess they would work too? Because they only deliver as much as
> the computer needs - right? And there is a 3A fuse in the vic20
> anyway... Have I understood this correctly?

Exactly correct. The only exception would be the so-called "wall
wart" types of supply (generally ones under 2 Amps). They are usually
unregulated, and a larger (higher current) unit might put out quite a
bit more voltage under the same load than a low current one. However, I
suspect the power supplies you mentioned are switchers and therefore
inherently regulated to put out no more than the rated voltage.
Switchers tend to be very small and light weight for the amount of
current they can supply in comparison to the C64 black brick which is a
conventional linear type.

Ray

[Leeeeee]

The sinuswave rectified would be as a lot of upward bows going from 0 to 9V at top right? And 9V DC would constantly be a top of 9V. So as a total, 9V DC would be more than a 9V AC????

/Anders

Nope, 9VAC will go from zero to plus 12.7V through zero and down to -12.7 and so on. The Root Mean Squared value of this waveform will be 9V which is the equivalent DC voltage into a resistive load.
The problem starts when you rectify the AC as the current is only drawn at the wave peaks so it becomes about 12VDC after rectification.

Lee.

[Boray]

But why would the vic-20 need 12V when only 9V and 5V is used inside? wouldn't it work with a 9V DC suplly anyway?

Hmmm..... Well, I measured, and out of my power supply comes 10.5V AC. After the rectifyer, it's 11V DC.

Could this be because they have increased the voltage of the
power outlets from 220 when the vic20 was built into
more like 225-230V today?

Maybe it's more healthy for the vic to buy one of those DC power packs....

I don't think there is anything wrong with the AC measuring of my multimeter. When I measue the power outlet, it's 225V and that's probably right...

/Anders