Power Supply

[Richard James]

If you make a PSU using those plug in adapters you avoid having to deal with electrical emission laws. If you designed it so that it took in power from the main and used a custom circuit board then also you would need to ensure that it was electrically safe as power supply.

You might get away with those issues if you make them for yourself but if you want to sell them then you might encounter legal difficulties.

[nbla000]

Yesterday my Cabletronic Amiga PSU is dead

I need to go to a repairman, i hope is just a fuse.

It has a red led, last evening when i powered on it the led comes red for an half second and after off but no smell of burning from it....

[eslapion]

If you make a PSU using those plug in adapters you avoid having to deal with electrical emission laws. If you designed it so that it took in power from the main and used a custom circuit board then also you would need to ensure that it was electrically safe as power supply.

You might get away with those issues if you make them for yourself but if you want to sell them then you might encounter legal difficulties.

This is precisely why I made the power supply like that.

I can see there is more good sense in this thread than on Lemon64 and comp.sys.cbm

My reply to this nice mess...

Fact: Did you inform me of the problem before publicly posting it? NO

Fact: Did you ask for a repair or replacement? NO

Fact: If you had known what was inside you would never have plugged it in??? How in the hell else would you expect a power supply of that nature to be built??? A transformer and switching PSU, both perfectly isolated, both with safety certifications. All PCs PSUs are built like that! The switching wallwart inside this box is the same kind provided with millions of internet gateways, wireless routers and other digital devices.

Obviously, not a single PSU in the world is good enough for you. This comment simply shows how ignorant you are.

In WHAT way was this a ripoff? I should have built nice looking fins on the box? I should have put a mechanical gerbil inside? NO!

I selected a 9Vac box and a 5Vdc box which met the required specifications. I tested them under no load and under full load and I made sure they both had legally valid certifications.

Now, you complain about the cosmetics of the insides... very bright.

I don't think I have anything else to add...

[eslapion]

@Jim Brain:

You said:

While I could see some value...

No, forget it, there are so many things wrong with the PSU, I can't
defend it at all.


o Wall Wart PSUs typically don't provide enough juice for the 5V leg of
a 64 with any amount of peripherals. I've seen 1.5A ones, but never larger.
o Extension cords were never meant or designed for that use. In a
pinch, sure, but not enclosed like that.
o Grounded plug, where are ye?


You know, I've got a HD original 64 PSU around here I'll ship you for
the cost of shipping, just to save you some pain. But, only if you
promise to make a web site and put this on it. I don't even think it
needs any significant description. This is classic, and it's not even
CBM specific.


Jim

I have to respond to that.

The 5Vdc switching wallwart is rated for 2.4A and is CSA/UL certified and so is the 9Vac transformer.

This PSU was AT LEAST 40% more powerful than a standard C64 PSU. Also, as it uses a switching PSU instead of a linear one, it normally produces much less heat and therefore was much less likely to fail.

Since both wallwarts are certified and the ratings are way above the requirements for operating a C64 with many things attached to it, excuse me for assuming that this should be safe and operate properly for a long time.

I think your post assumes things which are FALSE. For example, if a ground lug would have been added, what should I have connected it to? None of the two wallwarts had ground pins because they had plastic casings. The plastic enclosure is made of ABS which is an excellent electrical isolator.

In that case, a ground plug was neither required nor applicable. For example, original VIC-20 PSUs which were also galvanically isolated had no ground plug. Virtually no switching wallwarts available on the markets have a ground plug because they are galvanically isolated and have non-conductive casings.

Since I was not legally allowed to solder on the 120Vac side of the wallwarts, the only way to connect them safely is to use an extension with multiple outlets. Putting the outlet inside an electrically isolated case is perfectly safe and legal.

I also think a lot of other posts by other people concerning this PSU denote pure ignorance and irrationality.

If Dragos can post a picture showing the general insides of the box, he can certainly show pics of what printed on the wallwarts. If he doesn't then I will!

Many wall wart PSU's are not (properly) stabilized as well. Some output
a considerably higher voltage when they are only lightly loaded. In
other words: you do risk your vintage hardware when hooking it up to
these kind of PSU's.

Disinformation #2.

Many switching PSUs do have a minimum load. However this little one was tested with no load for voltages. It showed 5.1v @ zero load which perfectly acceptable.

I tested it with my own C64 and REU attached. The voltage fell to a very safe 4.95v.

These switching PSUs are sold for 9.99$ (more expensive than the SCSI box PSUs) at Addison electronics.

BTW, the minimum load of my SCSI Box PSU based high capacity power supplies is 500mA on the 5Vdc, half the power consumed by a C64 with nothing attached to it.

[dragos]

Without causing a huge disruption here, please read all the comments posted at lemon64. I think they will speak volumes, especially Francios' statements.

http://www.lemon64.com/forum/viewtopic. ... sc&start=0

[eslapion]

Without causing a huge disruption here, please read all the comments posted at lemon64. I think they will speak volumes, especially Francios' statements.

http://www.lemon64.com/forum/viewtopic. ... sc&start=0

Yes... it speak volumes of your ignorance. You paid 35$ for that thing well, this is how you make a SAFE C64 power supply for 35$. That's it!

[dragos]

I see. I cannot post insults but Eslapion can. I approached this matter without being a dick, and I get attacked. ah well, at least MY feelings were not hurt

[gklinger]

eslapion: Why do you post replies here to posts made elsewhere?

[eslapion]

eslapion: Why do you posting replies here to posts made elsewhere?

I am not a member of comp.sys.cbm nor do I wish to become one. I believe Mr. Jim Brain is a member here.

[carlsson]

Administrative comment: You don't have memberships in Usenet News. You could say that you're not a reader of the newsgroup, or using newsgroups at all but as long as you have a provider who carries certain groups, you can come and go as you wish.

Personal comment: I used to be very active in comp.sys.cbm and other groups until perhaps 1-1.5 years ago. The number of trolls grew louder, the signal to noise ratio dropped far below any web forum I've visited so nowadays I check the newsgroups once every 3rd month or even less. Most of the time, it is only flame wars or newbie questions posted anyway. I respect those devoted Commodore people who still hang around there - some even prefer Usenet over web forums - but I see most of them being active in one or another forum as well. Today, a newsgroup as comp.sys.cbm mostly acts like a missing link between people who visit two different forums.

When it comes to power supplies, a friend of mine tried to design a C64 power supply last year, but only on paper. I don't have the skills or guts to assemble it, and he barely has neither. After all, I have obtained enough number of "normal duty" PSUs to get me going, and rarely have more than one computer connected at a time anyway. If anyone is interested to see my friend's dabblings, I could scan his diagram and post here. But only if I can get a promise it won't turn into another flame fest pointing out how stupid someone can be for choosing this design over that.

[eslapion]

...Most of the time, it is only flame wars or newbie questions posted anyway.

I share this view and that's why I don't want to invest energy or time there.

When it comes to power supplies, a friend of mine tried to design a C64 power supply last year, but only on paper. I don't have the skills or guts to assemble it, and he barely has neither. After all, I have obtained enough number of "normal duty" PSUs to get me going, and rarely have more than one computer connected at a time anyway. If anyone is interested to see my friend's dabblings, I could scan his diagram and post here. But only if I can get a promise it won't turn into another flame fest pointing out how stupid someone can be for choosing this design over that.

Your friend's design might very well be excellent.

I myself, 2 years ago, designed a hysteresis based switching supply that was incredibly cheap and safe. However, since it is not CSA/UL certified, selling it is almost impossible. It always has to come with a warning that it might void your insurance policy etc. This is true for pretty much any device that has no safety certification.

Making anything that plugs into the wall outlet can void your home insurance if not safety certified.

That is why I will always recommend playing lego (connecting and integrating them as opposed to designing and making them) with components already safety certified and available on the market when it comes to making PSUs for old machines, Commodore or anything else.

Also, most publicly availale plans for making PSUs involve linear voltage regulation which produces a lot of heat. Most modern mass produced PSUs use switching technology which produces considerably less heat.

Making switching PSUs yourself can involve looking for components which are very difficult to find such as custom inductors of highly specific values. It can also involve complicated calculations which cannot be done by most people as it involves using complex number system (i=square root of -1). It also usually involves dealing with dangerous high voltages.

By using already made PSUs, you have multiple benefits: mass produced PSUs are cheaper, they are safety certified and will not void your home insurance, they almost always use switching technology which produces less heat and consume less power. Buying dozens of them results in getting homogenous and consistent characteristics from one unit to the next.

I try to design completely custom power supplies only when faced with a very specific application that demand it.

[gklinger]

I am not a member of comp.sys.cbm nor do I wish to become one.

Yet you're quoting posts made there so clearly you're reading it which directly contradicts what you just said.

This article is interesting and germane. Following the given advice could have prevented tragedies like this one.

[PaulQ]

I've given this a lot of though, and, well, here's my thoughts.

At first, when eslapion announced he was selling his power supplies, I envisioned that he was using an AT power supply, which already has a good 5VDC source, and a resistor to bring down the current on the 12VDC line. That's the way I think I would do it.

When I first saw the picture posted by Golan at Lemon, I never for a moment thought it was from eslapion. When I discovered that, I was in shock. Then I figured, hey, maybe eslapion really hates Dragos and was playing a joke on him.

Honestly, I think that the CSA/UL certification was invalidated the moment the wire ends were cut from the power supplies. Soldering them together onto a Commodore 64 power cord would further invalidate this certification. I mean, those certifications are pretty specific for every aspect of the design of the device they're applied to. I don't mean to insult or flame anyone here; that's just the way it reads. For instance, in many of my manuals, there is a line in the appendix under regulatory information which clearly states something to the effect of, "This equipment is UL-listed and CSA-approved for the uses described in this manual."

Like others, I am not an expert in this area. It's entirely possible that I am wrong. I do hope that I am. I have decided to defer to the experts in this case, and have sent an e-mail to certinfo@csa-international.org to ask them if the CSA certification would still be valid. I sent them a copy of the picture for reference. I am doing this so that we can all learn something from this, and put it to rest once and for all. I will post back with their response.

[PaulQ]

So far, I have received the standard form response as follows:

From: CertInfo [info@csa-international.org]
Sent: April 30, 2008 6:58 PM
To: Paul Quirk
Subject: Acknowledgment of Enquiry

We have received your request and on behalf of CSA International we would like to thank you for your inquiry. A representative from our sales department will be in contact with you soon.

Sincerely yours,



CSA International Sales Division


This message is intended only for the use of the person or organization to which it is addressed, and may contain information that is privileged, confidential and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, or responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by email and delete the original message immediately. The sender, its subsidiaries and affiliates, do not accept liability for any errors, omissions, corruption or virus in the contents of this message or any attachments that arise as a result of e-mail transmission. Thank you.


No virus found in this incoming message.
Checked by AVG.
Version: 7.5.524 / Virus Database: 269.23.6/1407 - Release Date: 30/04/2008 11:35 AM

Will keep you all updated.

[eslapion]

I've given this a lot of though, and, well, here's my thoughts.

At first, when eslapion announced he was selling his power supplies, I envisioned that he was using an AT power supply, which already has a good 5VDC source, and a resistor to bring down the current on the 12VDC line. That's the way I think I would do it.

Then you would likely destroy your Commodore 64.

The smallest AT power supply (and probably the only one still made) has a rating of 23 amps on the 5V and it has a minimum load condition of about 2A. In other words, if all you've plugged to the AT PSU draws less than 2A, you will get voltages much higher than 5V, possibly high enough to destroy all the digital electronics connected to it.

See: http://www.startech.com/item-specs/PS2P ... upply.aspx

Comparatively, the Commodore 64 with nothing attached to it other than a TV or monitor, consumes a little more than 1amp on the 5V line.

Compared to a modern PC, the Commodore 64 (or VIC-20) consume VERY little power. While I have to have a 430 watts PSU in my PC for safe and reliable operations, a Commodore 64, by itself consumes about 5 Watts on the 5V line and about 7 Watts from the 9Vac line. Thats a total of 12 Watts.

Of course, the draw on the 5V line can grow to nearly 2A if you use a Ram Expansion unit of 512k and/or a 80 column display card such as the B.I.80.

When I first saw the picture posted by Golan at Lemon, I never for a moment thought it was from eslapion. When I discovered that, I was in shock. Then I figured, hey, maybe eslapion really hates Dragos and was playing a joke on him.

Its no joke at all. A lot of people have seen this on other forums and were insulted because... they have their own custom power supply for Commodore 64s, 128 or Amiga (500-600-1200) computers and did it in exactly the same way. They have been perfectly well working for years.

Honestly, I think that the CSA/UL certification was invalidated the moment the wire ends were cut from the power supplies. Soldering them together onto a Commodore 64 power cord would further invalidate this certification.

Let me put this another way. Lets say you have a power supply for your internet router (actually, most of these things draw considerably more power than a C64) and for some reason, while passing the vacuum cleaner you damage the output cord of its PSU. You ask a friend who's good at using a soldering iron to put in place a replacement connector.

It works just fine and you can resume using your internet router and everything works fine. Did you void the CSA/UL certification? Absolutely not. You touched NONE of the high voltage components.

It is the responsibility of the manufacturer to ensure that the power supply (or wallwart, in this case) will have the necessary protections in case the newly soldered connector has a short circuit. Same thing, for example, if the power supply, before having this new connector had touched something metallic on the floor, such as a clothes pin, which would have short circuited it.

I mean, those certifications are pretty specific for every aspect of the design of the device they're applied to. I don't mean to insult or flame anyone here; that's just the way it reads. For instance, in many of my manuals, there is a line in the appendix under regulatory information which clearly states something to the effect of, "This equipment is UL-listed and CSA-approved for the uses described in this manual."

Well, what is the use described in the manual? Powering a device that is supposed to expect a specific voltage and drawing no more than a certain amount of electric current.

The commodore 64, in order to operate properly, requires a minimum of 1A on its 5V power input pins and about 750mA on its 9vac input pins. Also, for safety reasons, these two sources must be "floating" or "isolated" from one another.

The two wallwarts found in Dragos's box were both electrically isolated from the ground and had the following specifications:
- One 5Vdc @ up to 2.4A switching regulated supply
- One 9Vac @ up to 900mA transformer

In both cases, this is way more than the 64's basic needs. In fact, it is way more than the standard C64 power supply provides, about 40% more.

Like others, I am not an expert in this area. It's entirely possible that I am wrong. I do hope that I am. I have decided to defer to the experts in this case, and have sent an e-mail to certinfo@csa-international.org to ask them if the CSA certification would still be valid. I sent them a copy of the picture for reference. I am doing this so that we can all learn something from this, and put it to rest once and for all. I will post back with their response.

Doing that implies a distrust and a perception of malice that simply isn't there.

All of the above, I have had to explain and repeat time and time again on multiple forums.

Now, I am tired and I am pissed.

This is the RIGHT WAY to make a SAFE low cost power supply that works with a VIC-20cr or a Commodore 64 or Commodore 64c.