New Low-Cost 32k RAM expanders

[eslapion]

Shipping news!!

Yes, its TRUE!! A batch of new 32k expanders was shipped for the very first time today, exactly as planned!

Thank you for your encouragement to all who have purchased a multifunction expander.

Thank you to Dragos and Alan for your support.

I hope your new piece of VIC-20 hardware will serve you well for years to come.

[eslapion]

Instructions now available online!

Just in time before people begin to find their new expanders in their mailboxes.

Alan has created some very straightforward and easy to understand instructions on how to run virtually all software ever made for the VIC using the Ultimate expander.

Enjoy!

http://www.eskimo.com/~areed/vic/ultexp.htm

[Alan]

I received my Expander cartridge from Eslapion today. Wowee! Boffo! It's great! Zoinks!

I took a few pictures and wrote up a short review HERE IT IS

[Schlowski]

Received mine too, and as Alan said it's a great product!

Good review, btw.

Björg

[orion70]

Received mine, too. I only use it for cart ROMs (quite reductive, I know ) and it works great. Only one question: how to un-load ROMs loaded from disks? I mean: I load the appropriate ROM from floppy, push the reset button, et voila, here's my game/program/utility. But when I turn off the VIC, instead of having the startup screen, there's the ROM again! What should I do? Any way of resetting the EPROM other than unplugging the VIC, unplugging the cartridge, and plugging everything in again?

Thanks eslapion for the good job.

[Alan]

Received mine, too. I only use it for cart ROMs (quite reductive, I know ) and it works great. Only one question: how to un-load ROMs loaded from disks? I mean: I load the appropriate ROM from floppy, push the reset button, et voila, here's my game/program/utility. But when I turn off the VIC, instead of having the startup screen, there's the ROM again! What should I do? Any way of resetting the EPROM other than unplugging the VIC, unplugging the cartridge, and plugging everything in again?

Thanks eslapion for the good job.

I noticed this too when using loading cartridge games into BLK5. Seems the only way to get rid of them is to unplug the cartridge. Eslapion?

[idrougge]

I don't get this ROM option feature. Does the board have sockets for ROMs, or is it a surface-mounted ROM or flash chip?

[eslapion]

I load the appropriate ROM from floppy, push the reset button, et voila, here's my game/program/utility. But when I turn off the VIC, instead of having the startup screen, there's the ROM again! What should I do?

This is truly some unanticipated "feature" of the VIC expander. The surface mount version of the memory chip consumes so little power in data retention mode that it can keep it for quite a long time.

This appears to mostly occur if you have an older VIC with the 2 prong 9Vac power supply. These VICs have a large capacitor inside which can continue to feed the memory chip with the needed 2V to keep the memory chip in data retention mode.

While the VIC is off, some truly minute amount of power might also be flowing back from the serial (IEC) port or the video port.

I will have to investigate this carefully. If this is a problem, I can change the memory chip to a large DIP chip which does not have such a mode.

[eslapion]

I don't get this ROM option feature. Does the board have sockets for ROMs, or is it a surface-mounted ROM or flash chip?

The expander has a socket for a 27c256 EPROM. In order to ensure the longest possible lasting product, I use OTP ROM chips which can never be erased accidentally.

[idrougge]

So I, who have my own (27c256) EPROM burner, can skip the ROM option and add my own monitor or DOS wedge? I so, I'm interested.

[eslapion]

So I, who have my own (27c256) EPROM burner, can skip the ROM option and add my own monitor or DOS wedge? If so, I'm interested.

You sure can! However, normally, when I make an expander, I cover it with a couple of layers of conformal coating to protect it. I would have to skip this step.

If you can burn your own EPROM then perhaps a "do it yourself" expander is better for you. I suggest you take a look at post 39 and buy the kit version which is only 22$.

Also, when people pay for the options, this covers the cost of the extra needed switches and some extra parts. In the kit version, only one switch is provided.

If you want a ROMless kit that is ready to receive a ROM chip then you will have to provide the extra switches, a few surface mount resistors and two 1n6263 diodes.

[carlsson]

There is no kind of simple electronics that can consume a small bit of power in short time that you could add, like a "zap" button if it is easier or cheaper than replacing the type of memory chip? I don't know about this stuff, just an idea...

[Alan]

I took a few pictures and wrote up a short review HERE IT IS

I always wondered what kind of person quotes himself-- now I know.

I just thought I'd mention that I've added some more stuff to my review of the new Expander. I've had another day to play with it, after all, so I had some new observations.

The review is still HERE

[Thomas Hechelhammer]

One problem is figured out in Alans review:

The Expander does have one quirk: When you load a program into BLK5, a cartridge game for example, the game will often STAY in BLK5 no matter how long you leave your VIC powered off. When this happens, the only way to clear out BLK5 is to actually remove the cartridge. This only seems to affect 'auto-booting' cartridge games, like Avenger or Omega Race. A mild inconvenience, Francois is working on a solution.

There are two possible reasons:

1. The RAM cannot be used in the VIC PCB because it needs too much time loosing the stored information after removing the power. I'm only using RAMs of the KM-series which have no problems.

2. The capacity of the condenser is too high. Condensers serve supply voltage in high frequency and complex digital circuits. They work as tension or energy source in moments of high current and/or power demand. By their low impedance with high frequencies they reduce the impedance of superordinate voltage supply or their inlet and cause a mutually uninfluenced power supply of the partial circuits.

At first I would remove all condensors and see what happens. When the effect is still present but not with other expansions, the problem is definetly the RAM.
Next idea would be changing the RAM with RAM from a different producer.
It's possible that low-power RAMs keep the information longer than the old high-power RAMs.

[eslapion]

There are two possible reasons:

1. The RAM cannot be used in the VIC PCB because it needs too much time loosing the stored information after removing the power. I'm only using RAMs of the KM-series which have no problems.

Unfortunately, this is not the origin of the problem. As Alan said, unplugging the cartridge does erase the content of its RAM.

2. The capacity of the condenser is too high. Condensers serve supply voltage in high frequency and complex digital circuits. They work as tension or energy source in moments of high current and/or power demand. By their low impedance with high frequencies they reduce the impedance of superordinate voltage supply or their inlet and cause a mutually uninfluenced power supply of the partial circuits.

At first I would remove all condensors and see what happens. When the effect is still present but not with other expansions, the problem is definetly the RAM.

Once again, this explanation does not apply and for the same reason. If the capacitors on the expander itself were the problem, the data would not get erased when unplugging the cart.

The capacitors (the right word for what you call condensers) onboard the expander are 0.1 uFarad. This is only a tiny fraction of the internal VIC-20 capacitors. The early version of the VIC which uses a 9Vac power supply has an internal electrolythic capacitor of 4700 uFarad.

Next idea would be changing the RAM with RAM from a different producer.
It's possible that low-power RAMs keep the information longer than the old high-power RAMs.

The low-power RAMs don't just "keep the information longer. As I said earlier, the have a special "data retention mode" which is normally used with lithium batteries.

What I would need to know from anyone of you is if this problem also occurs on the CR version of the VIC-20 which has a different type of power supply. The CR generally has the same type of power supply as the commodore 64 and uses a round 7 pin DIN power supply connector.

There is no kind of simple electronics that can consume a small bit of power in short time that you could add, like a "zap" button if it is easier or cheaper than replacing the type of memory chip? I don't know about this stuff, just an idea...

I don't think this would be a good idea. I had reports that the data could be kept up to 1 hour. This means a good amount of energy is left in the VIC. This button would effectively short the 5V feed from the VIC. Pressing the button while the VIC is ON could damage it and even while it's off, it's a lot of energy to bleed off.

I follow this closely but yes, the solution at this point seems to be a replacement of the RAM chip with one that does not have a data retention mode.

Technical note:
In the VIC, the only component that still consumes power when fed with less then 4V is the red LED. However, as the voltage drops, eventually it reaches about 2.1V and below that voltage the LED cannot consume any current. That is still enough to maintain the data.

The only difference between an older memory chip and the newer surface mount ones for the VIC is that the old ones loose their content when fed less than 4V while the new ones loose their content when fed less than 2V.

Any technical detail is welcome, please PM me any details about your configuration you believe is important.