Going on a VIC raid

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carlsson
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Postby carlsson » Thu Dec 15, 2005 3:00 pm

carlsson wrote:
I didn't buy all the homemade ones, only the most interesting ones.


Unfortunately, I still don't own a digital camera, so you'll have to live with my verbose explanations:


1. Black, slightly oversized case (14*9.5 cm, compared to the standard 14*8 cm) which has been modded to fit a switch on one side. The case reads "SPECIAL CARTRIDGE by audio computers", but I believe it is a generic case with four screws for easy disassembly. Inside is a printed card with the marking "32k system x-rom". There is room for a 8K chip, but it is empty. There are a bunch of chips, of which two TMS4416-20NL and room for two more. Those are the same type of RAM chips as the Commodore 16 has, by the way. It appears to be a memory expansion up to 32K with optional ROM. When plugged in, it identifies as a 16K expansion. If I flip the switch, the first 8K block seems to be disabled, but the second block still holds any data I put into it.

2. VIC-1110 8K RAM cartridge modded with two times four DIP switches. Despite once have being modded, it is hard to open without cracking it, so I didn't. It appears to be a fully switchable 16K expansion as follows:

LEFT 0001 RIGHT 0000 = 8K expansion
LEFT 0000 RIGHT 0001 = 8K expansion
LEFT 0001 RIGHT 0010 = 16K expansion
LEFT 0001 RIGHT 0100 = 8K at BLK1 + 8K at BLK3
LEFT 0001 RIGHT 1000 = 8K at BLK1 + 8K at BLK5

If more than one switch in each block is ON, that block is disabled just like if all switches would be off. I didn't dare to configure both sets of switches to the same value. Apparently, it does not support 3K expansion.

3. Grey/white (top/bottom) cartridge with only the company label. Case by Handic. It appears to be an 8K memory expansion. No switches, but once opened, it reveals two empty sockets and a total of four HM6116P chips, which indeed are 150 ns 2Kx8 RAM chips, and it sums up to 8K. The sockets are labeled to take one 4K EPROM each, and there are solder pads to select which block the EPROMs should go into.

4. White Handic cartridge with homemade software: "Extended Basic by Zyntax Zoft". Inside a small card from Datatronic with two sockets, one filled with the Extended Basic EPROM. It boots with the following screen:

Code: Select all


*** EXTENDED BASIC ***

3581 BYTES FREE

READY.


White border, white background, blue text. I will need to dump this to find out the commands.

5. Ditto homemade cartridge: "Spell it big". Same kind of card and configuration inside. Appears to be a BASIC program stored in BLK5, as the instructions tells you to POKE44,160:RUN. The program was written by Stefan Modin (probably one of those who got paid 5000 SEK/month) on January 4th, 1983. After some slow initialization involving copying character set at double size to RAM, one gets to choose colours on border, screen and characters, and is then presented with some kind of full screen editor where you can type messages. Probably some keyboard training course for people with bad eye sight. When a line is full, some strange action takes place to make room for a new line.

Oh well, nothing really amazing, but still a nice trip. At least I have memory expansions enough to sell.

In my previous message, I didn't mention that the guy had a drawer full of empty VIC-20 cartridge cases, the white variety from Commodore or Handic. He also had a few of those Datatronic boards, but unpopulated. I guess it might be interesting to someone as well, i.e. for manufacturing Leif's disk utility cartridge. Perhaps they should not be widely distributed, in case it a risk of creating false copies of other cartridges.
Anders Carlsson

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Postby Bacon » Thu Dec 15, 2005 4:08 pm

If you do get back there, I'm still interested in a VIC-20. From your description I can't blame you for not picking one up.

I wouldn't mind having a PET of some sort, and a disk drive for it, but I'm not sure I have the room. Will have to think about it.
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carlsson
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Postby carlsson » Thu Dec 15, 2005 4:16 pm

I remember he said he had thrown away a lot of cables, which might be a Bad Thing if those cables would be IEEE cables going between the computer and disk drive. If I recall correctly, such cables are not easy to obtain or create these days. He also had dozens of loose PET keyboards, but I didn't see any VIC/64 keyboards other than those inside computer cases.
Anders Carlsson



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Boray
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Postby Boray » Fri Dec 16, 2005 5:57 am

Whoops! Sorry for edeting your post! I pressed edit instead of quote by mistake. But luckily, I could get the text back by pressing "back" in the browser a couple of times, or it would have been lost...


carlsson wrote:2. VIC-1110 8K RAM cartridge modded with two times four DIP switches.


Sounds exactly as the 16K cartridge my brother built of a 8k cart.

And if you just put switches on a standard 16k cart, they would work that way too...

/Anders
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carlsson
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Postby carlsson » Fri Dec 16, 2005 7:32 am

Yes, I remember that the 8K and 16K cartridges share the same circuit board, only that 8K is half populated to begin with.
Anders Carlsson



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carlsson
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Postby carlsson » Fri Dec 30, 2005 2:09 pm

carlsson wrote:Inside is a printed card with the marking "32k system x-rom".

On Monday, I bought a cheap digital camera (those who follow my rants in Vintage Computer Forum already know), so I took a picture of this board, both for documenting purposes and to learn the camera's limitations. A such picture should be taken with macro, full detail and no smoothing, but I still don't know quite all the other settings.

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(Click to get a full sized version)

The back side has a marking "B&T", but nothing more. I wonder about the row of holes on the middle, maybe it would be possible to connect a pass-through female connector. I could trace the lines for the 8K location, but I assume it maps to BLK5 or so. All in all, a rather advanced 16-32K memory expansion.
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Leeeeee
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Postby Leeeeee » Fri Dec 30, 2005 7:08 pm

Only 16K RAM fitted but with the pads for the other 16K.

The X-ROM position is for a ROM and not an EPROM so it's not much use as is, unless you can get hold of and program the nearly unobtanium 24 pin 8K EPROM.

I'd guess you're right about being able to fit a passthrough socket as well.

Lee.

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carlsson
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Postby carlsson » Sat Dec 31, 2005 6:32 am

How does one determine between a ROM and an EPROM space? Although I'd not experiment, I thought any 24 pin EPROM (I have a D2732 here) might fit and work. Assuming the board was populated with another 16K RAM and a cartridge socket, I get the feeling the companion ROM is something meant to copy cartridges.
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Postby Leeeeee » Sat Dec 31, 2005 7:07 am

I don't think the 24 pin 8K ROM pinout is directly compatable with any standard EPROM pinout. 8K compatable ROMs are devices such as..

Signetics 82S641
Harris 76641
AMD 27S49
Fairchild 93Z565

.. for which I don't have the pinout handy.

Lee.

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Postby idrougge » Sat Jan 28, 2006 2:50 pm

carlsson wrote:Documentation? Manuals? Magazines? He had a small pile of Swedish PET magazines and the early issues of VIC=Nytt and VIC=Rapport.


I'd love some.
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Postby ral-clan » Mon Jan 30, 2006 9:37 pm

carlsson wrote:Inside is a printed card with the marking "32k system x-rom".


I have one of those too (as I posted in another forum):

Image

Here is the back where you can see there are FOUR swiches :o . This is very bizarre, because I have four DIP switches soldered onto the same place that you have a throw switch (compare pictures of circuit board below with CARLSON's in message above).

Image

Guess, what! Inside it's just like yours, but mine is fully populated with RAM chips. I guess I can get 32K RAM, but I don't know how to set it properly :? . I've only managed to get a totaly of 28K on my VIC by playing around with the switches:

Image

As for making a pass-thru slot...look what is silk-screened on the board: LABEL THIS SIDE. There is a place where another chip can be soldered on (to the right in the photo) marked X-ROM and in small print 8K J1. As stated above, it's probably for a ROM, but what kind of ROM would go there?

Image

10 DIP switches sounds like an odd number, maybe it is 2*4 to configure each block of 8K to a memory position?


Well here is a picture of the other RAM expander I have. It has 10 switches (well, really 2 and 8 )....what would they be for and why so many??? The board has no manufacturer label, but is marked 16K RAM/ROM EXPANSION.

Image

SO many questions! Can anyone clear up the mysteries?

Very intriguing cartridges.

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Schema
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Postby Schema » Sun Feb 12, 2006 9:01 am

Leeeeee wrote:The X-ROM position is for a ROM and not an EPROM so it's not much use as is, unless you can get hold of and program the nearly unobtanium 24 pin 8K EPROM.


Would these be the Motorola MCM68764 ? I have a handful of these actually. Unfortunately my EPROM burner doesn't handle them directly.

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Re: Going on a VIC raid

Postby Ghislain » Fri Feb 24, 2006 10:55 am

carlsson wrote:We'll see what he has to offer. I'm mainly looking for VIC cartridges, but if he has other interesting VIC/64 items, I might pick them up too. Ten years ago, he was still asking the 1983 list price for his items, but now he sound more flexible. If I find a Bridge, Turtle Bridge or some other rather (heh) uncommon item, I might be willing to pay the list price. I'm thrilled!


When I was going to college in a small town around 1993, I saw an advertisement for "VIC-20/Commodore 64 Items Clearance Sale" at the local music/electronics store (the only one in that town). When I came in and asked to look at the stuff, the store owner seemed shocked that his advertisement actually attracted a customer.

Anyways, most of the VIC-20 items were software programs on cassette. And I could tell that they were pirated copies because of the way the labelling was done. Prices for the software was $30 and upwards for each item (as the store was probably charging for it 10 years earlier). And he was still asking for those prices even though the advertisement was supposed to be a clearance sale! Anyways, I didn't buy anything (I was hoping he'd just sell me all of the VIC-20 software for something like $25 or $1 a tape).

That store was notorious for selling pirated music cassettes in the 1980s and trying to pass them off as real. I think the store owner got into a lot of legal problems because of it. And here he was in 1993 still trying to sell pirated software (at the original listed price) that had been obsolete(*) for 10 years!

(*) We VIC-20 enthusiasts don't consider VIC software to be obsolete by any means of course, but I was speaking from the general public's point of view.
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Re:

Postby MiaM » Thu Nov 09, 2017 8:38 am

Sorry for thread necrophilia deluxe, but I've had one of these boards myself once upon a time.

IIRC I soldered in a pass through connector on mine. I think I had four dip switches, but my memory may be incorrect.

I also had a three port motherboard that were obviously from the same manufacturer. That surely had a switch on the left side. It also had sockets for one or two ROM's, and maybe some dip switches. I don't remember all details but I think the switch swapped block 5 and another block for atleast one of the cartridge slots, I.E. obviously meant to make it easy to pirate copy cartridges.

I've never heard of any software sold on ROMs/EPROMs so the sockets must obviously also have been meant for pirate copies of common cartridges.

AFAIK the cartridges that a "pro user" might want to have were vic-mon, programmers aid (side by side in each half of block 3), super expander and maybe the ieee-488 cartridge (side by side in block 5). With theese eprom sockets you could have super expander and atleast one more copy of a cartridge.

ral-clan wrote:Guess, what! Inside it's just like yours, but mine is fully populated with RAM chips. I guess I can get 32K RAM, but I don't know how to set it properly :? . I've only managed to get a totaly of 28K on my VIC by playing around with the switches:


Well, you can't get more than 28-29k free ram for BASIC. The last 8k is in block 5, you can for example load a copy of most autostart cartridges there.


[quote="Leeeeee"The X-ROM position is for a ROM and not an EPROM so it's not much use as is, unless you can get hold of and program the nearly unobtanium 24 pin 8K EPROM.[/quote]

But a 4K EPROM will fit AFAIK, so you can for example have a copy of SUPER EXPANDER there.


P.S. it would be nice to have theese cartridges reverse engieered. It would be interesting to know how the ram is refreshed. The four 74LS157's is 4*4 two input mux'es, while the DRAM's have 8 address inputs. So I guess that two of the 74LS157's select two parts of the CPU adress bus while the other two switches between the first two and a set of counters for refresh address. It's hard to see in the photo but one or two of the IC's in the upper right corner could possible counter(s).

It's also interesting that there is a CD4050. Those aren't supposed to play well together with TTL IC's :)

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Re: Going on a VIC raid

Postby eslapion » Fri Nov 10, 2017 12:17 am

MiaM wrote:Sorry for thread necrophilia deluxe, but I've had one of these boards myself once upon a time.

I've been on Denial for 11 years now and I really like it when every now and then somebody revives a thread that dates back before I was a member.


P.S. it would be nice to have theese cartridges reverse engieered. It would be interesting to know how the ram is refreshed. The four 74LS157's is 4*4 two input mux'es, while the DRAM's have 8 address inputs. So I guess that two of the 74LS157's select two parts of the CPU adress bus while the other two switches between the first two and a set of counters for refresh address. It's hard to see in the photo but one or two of the IC's in the upper right corner could possible counter(s).

It's also interesting that there is a CD4050. Those aren't supposed to play well together with TTL IC's :)

All the memory expansions I have sold are based on 32k and 8k static RAM chip because they are now cheap. They were quite expensive in the early 80s hence the incentive to develop DRAM based expansion.

I'd love to get my hands on an expansion like that as I have yet to find a good complete schematic for a functional DRAM based expansion for the VIC-20. Looking at the C64 schematics, you can understand what's necessary to access DRAM but the refresh part is all hidden in the VIC-II.
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