Issues with my Vic 20

[eslapion]

Also, if I follow your thinking, I guess its a good idea to suggest to people NOT to put heat sinks on their VIC chip... after all since it is Eslapion who suggest it, it can only be because he wants to rip you off peddling his little junkie metal clips.

Actually, what it is is your arrogance in telling people that your heat sync would have saved their Vic whenever this chip fails. You assume that it overheated and failed, even though there's nothing to suggest that this is actually a problem with this chip outside of your observations that it gets warm.

Fact is, when I got my first Vic 20, I would set it on a carpeted floor in the living room, completely blocking the bottom vents, and it would be left on for hours, if not days, at a time like this. Sometimes, I would bring it into my bedroom and set it on my bed while I wrote my programs. Of course, I was only twelve, and at that point learned a lot about physics from the Bugs Bunny and Road Runner show. One would think that if heat was a huge problem for this chip, it would have had a meltdown during one of those long summer weeks it lived at the end of my bed, powered on.

Here we are, 24 years later. The Vic is used on a desk. This means the vents are not being blocked. It is on, at best, an average of a couple of hours a week. It has a heat sync on the chip. Yet it appears to have failed.

What I am suggesting is that what you are offering may in fact be false sense of security to Vic 20 owners who ought to be watching out for something else. You make it sound as though the only problem with this chip is that it will overheat. I suspect that the power supply may be a bigger issue.

As for my choice of power supply, I have come to the conclusion that the ideal solution will be to modify one of my Commodore 128 PSU's to work with my Vic and C64. You can keep your wall warts and extension cord; please don't try to peddle that solution anymore.

So according to you, its not a good idea to have a heat sink on the VIC chip?

Its not a good idea to make your own PSU using modern and reliable parts that won't fry your computer either? If that is so, how come your Commodore brick fried your VIC? (at least, according to you...)

Apparently, its even arrogant to claim doing either of these things could prolong the life of your Commodore computer.

As for peddling... I don't sell any wallwarts. They can be found pretty much at any good electronics store. Same thing for the heat sinks, you can buy mine but any other small PC video card RAM chip heat sinks can do just as well.

As for the long summer week-ends, as I said, damage is cumulative. Putting a heat sink today will not undo the damage done in the past. Its like you're saying putting fresh prestone in your car today will prevent your radiator from busting after years of neglect.

I think your suggestions are pretty surprising but i don't think anyone should pay attention to them. At least now we know that following them has detrimental consequences...

[ral-clan]

To steer the topic a little bit:

This is the first thing I've heard about C128 power supplies being convertable to use on a VIC-20 or C64. I have a spare C128 power supply. Is this conversion feasable for use only with DIN power connector VIC-20s?

And....is there anything us owners of 2-prong VIC-20's can do about modern replacement power supplies? From what I gather, a lot of the transformer guts are inside the 2 prong VICs.

[eslapion]

This is the first thing I've heard about C128 power supplies being convertable to use on a VIC-20 or C64. I have a spare C128 power supply. Is this conversion feasable for use only with DIN power connector VIC-20s?

Unfortunately, the short answer is: Yes

2 pronged VICs require far more 9Vac current than C128 power supplies can provide.

However, technically, it should be possible to modify a 2 pronged VIC to consume regulated 5Vdc from an external source and therefore draw power in a manner similar to C64s and VIC-Crs.

And....is there anything us owners of 2-prong VIC-20's can do about modern replacement power supplies? From what I gather, a lot of the transformer guts are inside the 2 prong VICs.

As I said in the past, it should be possible to replace the big 5V regulator inside these VICs with modern switching regulators.

You can either use TIs integrated switching regulators such as the PT78ST105 and other members of the same family or make your own switching regulator such as the one used in jsaily's home made power supply.

[PaulQ]

So according to you, its not a good idea to have a heat sink on the VIC chip?

If it gives a person a false sense of security, yes.

Its not a good idea to make your own PSU using modern and reliable parts that won't fry your computer either? If that is so, how come your Commodore brick fried your VIC? (at least, according to you...)

I never said that.

Apparently, its even arrogant to claim doing either of these things could prolong the life of your Commodore computer.

No, it's arrogant to claim that a heat sync on this chip would have saved a chip from burning out without considering other causes.

As for the long summer week-ends, as I said, damage is cumulative. Putting a heat sink today will not undo the damage done in the past. Its like you're saying putting fresh prestone in your car today will prevent your radiator from busting after years of neglect.

Microchips do not take radiator fluid; the chemistry is completely different. Thus far, your assertions continue to go unsubstantiated. Can you demonstrate that this chip slowly damages itself over the years from the heat it generates?

This is the first thing I've heard about C128 power supplies being convertable to use on a VIC-20 or C64. I have a spare C128 power supply. Is this conversion feasable for use only with DIN power connector VIC-20s?

That's what this person has done: http://qotile.net/cynthcart.html

[ral-clan]

In doing some web-searching, I found this source for new old stock MOS6560 chips. I'm not sure how legit the site is:

http://www.wt.co.th/?code=610-04800-1

[eslapion]

This is the first thing I've heard about C128 power supplies being convertable to use on a VIC-20 or C64. I have a spare C128 power supply. Is this conversion feasable for use only with DIN power connector VIC-20s?

That's what this person has done: http://qotile.net/cynthcart.html

This link in no way says how to modify a two pronged VIC to work with a C64 or C128 power supply... it only says the guy thinks a modded C128 PSU is the best power supply for a C64.

In my opinion, a C128 PSU is much better than an original brick but it is not as safe and as reliable as a modern switching wallwart. Old power supplies, even if they are better than linear ones remain old power supplies.

Before you blast me with all the junk you're used to, I would like to point out that ALL power supplies eventually fail and they are the greatest single source of computer failure. What really matters is not IF a power supply fails but what happens when it does. A modern power supply made with quality parts will NEVER damage the computer of electronic apparatus it powers when it dies, it will just shut itself off...unless it been opened and tampered with.

Switching wallwarts are now used to power (or recharge) everything from cell phones and PDAs to expensive electronic instruments. We use wallwarts to recharge multi thousand dollars Fluke portable scopes as well as powering FPGA development boards. Just like any other PSU, they fail every once in a while and we get them replaced but they NEVER damaged any equipment, or represented a fire hazard in any way or injured anyone.

Do I sell any? NO!

No, it's arrogant to claim that a heat sync on this chip would have saved a chip from burning out without considering other causes.

A heat sink CAN save a chip from burning out. Does that mean YOU should not consider other causes? I hope not.

I certainly never said you shouldn't.

Its rather monolithic thinking to assume a heat sink (...not heat sync...) will always save your chip no matter what happens because it can prevent it from suffering damage caused by heat. If that's what you understand from what I said then I have to ask if you've been diagnosed with autism...

Anyways, if you stil don't believe high temperatures can damage a chip, you should take a look at this book.

ALL semiconductors suffer cumulative electron displacement damage from higher temperatures AND/OR radiations. In the case of NMOS chips, anything above 55C is detrimental.

[PaulQ]

This link in no way says how to modify a two pronged VIC to work with a C64 or C128 power supply...

Clearly then, I was not referring to the two pronged Vic, was I?

In my opinion, a C128 PSU is much better than an original brick but it is not as safe and as reliable as a modern switching wallwart.

Please explain in what way is the Commodore 128's switching power supply less safe than a cheap wall wart switching power supply.

Before you blast me with all the junk you're used to, I would like to point out that ALL power supplies eventually fail and they are the greatest single source of computer failure. What really matters is not IF a power supply fails but what happens when it does. A modern power supply made with quality parts will NEVER damage the computer of electronic apparatus it powers when it dies, it will just shut itself off...unless it been opened and tampered with.

Are you suggesting that the Commodore 128's switching power supply will not behave in this manner?

Switching wallwarts are now used to power (or recharge) everything from cell phones and PDAs to expensive electronic instruments. We use wallwarts to recharge multi thousand dollars Fluke portable scopes as well as powering FPGA development boards. Just like any other PSU, they fail every once in a while and we get them replaced but they NEVER damaged any equipment, or represented a fire hazard in any way or injured anyone.

That's nice. I've never heard of a Commodore 128 PSU damaging any equipment or representing a fire hazard or injuring anyone; so I'm still unclear as to how it's less safe.

A heat sink CAN save a chip from burning out. Does that mean YOU should not consider other causes? I hope not.

I certainly never said you shouldn't.

You seem to suggest it's the only reason why it fails:

6560 overheated and died... as usual.

Just a small little heat sink would have saved it.

Its rather monolithic thinking to assume a heat sink (...not heat sync...) will always save your chip no matter what happens because it can prevent it from suffering damage caused by heat.

Perhaps you and I are talking about different things. Is your heat "Sink" like a kitchen sink, or more like a bathroom sink?

If that's what you understand from what I said then I have to ask if you've been diagnosed with autism...

No, that's exactly what you wrote. It's common for you to state that a person's 6560 failed due to heat; you do this all the time. See quote above for reference.

Anyways, if you stil don't believe high temperatures can damage a chip, you should take a look at this book.

ALL semiconductors suffer cumulative electron displacement damage from higher temperatures AND/OR radiations. In the case of NMOS chips, anything above 55C is detrimental.

I'm not denying that excessive heat causes failure. What I'm saying is that there is a lack of evidence demonstrating that the 6560 in the Vic 20 suffers from levels of heat to cause it to fail. Unless you're suddenly an expert in thermology, what independent source is there to substantiate your claim?

[eslapion]

This link in no way says how to modify a two pronged VIC to work with a C64 or C128 power supply...

Clearly then, I was not referring to the two pronged Vic, was I?

Then its my feeling you were not answering Ral-clan's question.

In my opinion, a C128 PSU is much better than an original brick but it is not as safe and as reliable as a modern switching wallwart.

Please explain in what way is the Commodore 128's switching power supply less safe than a cheap wall wart switching power supply.

When I say less safe, I don't mean for you or your house. I mean it has a greater likelyhood of damaging your machine. Altough cases of C128 PSUs destroying the machine they power are considerably fewer than with original bricks, just like with disaligned 1571s, there are a couple.

When the C128 PSU was designed, switching PSUs were in their infancy.

Good quality MOSFETs with low "ON" resistance that dissipate little heat weren't available. Many lower power PSUs didn't even use MOSFETs and many of them had a very poor power factor because they consume electrical current in a very irregular manner.

As I recently illustrated in a post addressed to Groepaz on Lemon64, the power factor of C128 PSUs sold in north america is very poor.

While the level of efficiency of a good switcher is around 90%, the efficiency of both C128 PSUs I have here is barely above 50%. Comparatively, the efficiency of the C64 brick is around 30%. More heat always contributes to shorten the lifespan.

Also, the feedback systems of these things is fully based on analog chips that were slow to react. If one of them fails, it can briefly expose the machine to a much higher voltage than the rated output.

If you look at more modern switching PSU controllers like the LM3524 or TL494, these use a combination of analog and digital circuitry which forces a shutdown in specific conditions.

Damage to the powered device can also occur because of other reasons I mention below.

Before you blast me with all the junk you're used to, I would like to point out that ALL power supplies eventually fail and they are the greatest single source of computer failure. What really matters is not IF a power supply fails but what happens when it does. A modern power supply made with quality parts will NEVER damage the computer of electronic apparatus it powers when it dies, it will just shut itself off...unless it been opened and tampered with.

Are you suggesting that the Commodore 128's switching power supply will not behave in this manner?

It can and it has. Much less frenquently than Commodore bricks but like I said, it has happened.

Sometimes this is not necessarily attributable to a design flaw. C128 PSUs have venting holes. Through the years, all sorts of dust, insects, liquids can infiltrate through those venting holes and affect the performances of components inside. In such a case, the simple fact that a switching wallwart has less age can make it more reliable and safer for your Commodore computer.

There is also the classic problem with aging electrolithic capacitors... no PSU is immune to that.

Switching wallwarts are now used to power (or recharge) everything from cell phones and PDAs to expensive electronic instruments. We use wallwarts to recharge multi thousand dollars Fluke portable scopes as well as powering FPGA development boards. Just like any other PSU, they fail every once in a while and we get them replaced but they NEVER damaged any equipment, or represented a fire hazard in any way or injured anyone.

That's nice. I've never heard of a Commodore 128 PSU damaging any equipment or representing a fire hazard or injuring anyone; so I'm still unclear as to how it's less safe.

Injuring anyone or causing a fire hazard, I have never heard either. Damaging a C128 and destroying a 1750 REU, I have heard...

Power supplies used in PCs and clones of that era have done that too. They use pretty much the same SCR/BJTs technology. A 22 y.o. power supply is... a 22 y.o. power supply, even if its a better one.

As said above, its not less safe to you. Its less safe to your equipment.

That being said, according to my experience, its still much safer than an original brick.

A heat sink CAN save a chip from burning out. Does that mean YOU should not consider other causes? I hope not.

I certainly never said you shouldn't.

You seem to suggest it's the only reason why it fails:

I really hope not.

Its rather monolithic thinking to assume a heat sink (...not heat sync...) will always save your chip no matter what happens because it can prevent it from suffering damage caused by heat.

Perhaps you and I are talking about different things. Is your heat "Sink" like a kitchen sink, or more like a bathroom sink?

Its more like that...

It's common for you to state that a person's 6560 failed due to heat; you do this all the time. See quote above for reference.

I firmly believe the main cause of 6560 failure is prolonged exposure to heat.

Its not the only one.

Since the original MOS 6502 and MOS 6522 VIAs used in the VIC-20 and 1541 drives both use the same NMOS technology, why do they fail much less often comparatively?

The 6560 can fail for the same reasons as the 02s and VIAs, such as static electricity discharge or short circuits/innapropriate voltages caused by failed or failing external components yet the 6560 fails considerably more often.

BTW, if your 6560 would have been damaged by a higher voltage from the PSU, its likely the VIAs or 6502 would also have suffered damage. All these chips use the same technology and all run on the same 5V source.

I'm not denying that excessive heat causes failure. What I'm saying is that there is a lack of evidence demonstrating that the 6560 in the Vic 20 suffers from levels of heat to cause it to fail. Unless you're suddenly an expert in thermology, what independent source is there to substantiate your claim?

The type of doping used in Commodore's NMOS technology is well known. It was also used in other chips of this era. Considering the properties of this type of semiconductors and the impact of temperature on it is well documented, all you need is a mean of verifying its temperature while it is operating, preferably with the VIC case closed and the metal shield in place.

My favorite tool for doing that is a K type thermocouple. Using that, I discovered that the 6560 operates at "borderline" temperatures. Did you ever bother to check the current drwn by the 6560? Its very interesting. Apply V*I=P and you could have a nice surprise...

Another chip that is often overlooked but that also operates at potentially damaging temperatures is the 64's/128's SID, specifically the 6581.

The 8580 does not dissipates as much heat.

[ral-clan]

One questions I've never found and answer for is: if heat can shorten the life of electronic components, why did Commodore embed the guts of their power bricks inside a huge block of epoxy resin? You would think that would cause heat to be trapped, and act like an insulator.

[PaulQ]

Then its my feeling you were not answering Ral-clan's question.

He actually asked two questions. I answered the first. Go back and read it again.

When I say less safe, I don't mean for you or your house. I mean it has a greater likelyhood of damaging your machine. Altough cases of C128 PSUs destroying the machine they power are considerably fewer than with original bricks, just like with disaligned 1571s, there are a couple.

Even modern power supplies have a potential of damaging a machine; but typically, this is attributed to a manufacturing defect rather than in the design itself. You have yet to present any evidence demonstrating that the design of the 128's PSU would lend itself to an increased likelihood of damaging a machine.

By the way, it's "Likelihood" and "Although."

When the C128 PSU was designed, switching PSUs were in their infancy.

I thought you'd know your electronics history better than that. In 1976, switching PSU's were in their infancy. By the time the Commodore 128 was released nine years later, it had matured sufficiently.

http://powerelectronics.com/power_manag ... ngle_chip/

As I recently illustrated in a post addressed to Groepaz on Lemon64, the power factor of C128 PSUs sold in north america is very poor.

While the level of efficiency of a good switcher is around 90%, the efficiency of both C128 PSUs I have here is barely above 50%. Comparatively, the efficiency of the C64 brick is around 30%. More heat always contributes to shorten the lifespan.

Not if the product has been engineered to handle the extra heat. I have power supplies that are twice as old as the one I used for my Vic 20 that still work to this day, but they become considerably hotter. Some are hot enough to heat a small room in the winter!

Also, the feedback systems of these things is fully based on analog chips that were slow to react. If one of them fails, it can briefly expose the machine to a much higher voltage than the rated output.

Depending on how high and how long, it may not even be something to worry about in a computer like a Vic 20.

Sometimes this is not necessarily attributable to a design flaw. C128 PSUs have venting holes. Through the years, all sorts of dust, insects, liquids can infiltrate through those venting holes and affect the performances of components inside. In such a case, the simple fact that a switching wallwart has less age can make it more reliable and safer for your Commodore computer.

What you are citing here are environmental concerns. The venting holes in the 128's PSU are very tiny and do not lend themselves to permit easy access for insects and dust, but obviously liquids will damage most power supplies.

Injuring anyone or causing a fire hazard, I have never heard either. Damaging a C128 and destroying a 1750 REU, I have heard...

Again, the same could be said for a defective modern PSU, and what you present here is known as heresay; not fact.

I firmly believe the main cause of 6560 failure is prolonged exposure to heat.

Again, you fail to present hard evidence to substantiate your claim; hence, it will, for now, remain only a "Belief."

EDIT: Fact of the matter is, many of the 6560 chips did not go back in the day. Another fact is that the brick power supplies are starting to fail more and more, and are known to fail in a manner which could damage the computer. I think it possible that the 6560 is more sensitive than other chips, possibly because it does run hotter, which may lead to it failing first. Telling people it fails because of heat may cause them to replace the chip or their Vic, put on a heat sync, but continue to use the same failing power supply which otherwise seems to work. This false sense of security may cause them to go through a few 6560's before they realize what's going on.

[PaulQ]

One questions I've never found and answer for is: if heat can shorten the life of electronic components, why did Commodore embed the guts of their power bricks inside a huge block of epoxy resin? You would think that would cause heat to be trapped, and act like an insulator.

The epoxy used actually is a heat conductor, and this was done in a lot of PSU's of the day.

[ral-clan]

Okay, if the power supplies fail and take the computer with them, than what is the use of all those fuses?

In my two-prong VIC there is a fuse inside the power supply AND another one inside the VIC-20 itself.

Do they not protect (at two stages) against improper power flow?

[PaulQ]

Okay, if the power supplies fail and take the computer with them, than what is the use of all those fuses?

In my two-prong VIC there is a fuse inside the power supply AND another one inside the VIC-20 itself.

Do they not protect (at two stages) against improper power flow?

There is only one fuse inside my Vic, and the Vic works (well, used to work) fine without it; so its purpose is clearly not for protecting the Vic. I think it has something to do with the cassette port.

It sounds as though the two pronged Vic may have a superior power supply design. My Vic's power supply has no fuse.

[ral-clan]

That's interesting. I think, but am not sure, that when the fuse blows inside the 2-prong VIC, the machine doesn't work at all (can anyone confirm?).

I do know that when the fuse blows inside the power supply, the VIC doesn't turn on at all (I've had to replace that fuse once - I think it's a 2.5V 0.5A or maybe the other way 'round).

[Schlowski]

In my first VIC back in the days I managed to blow that inside-fuse a couple of times (with a hand-made cassette interface...). Every time the VIC doesn't show any live until the fuse was replaced.