The Future

Luzur · Post by **Luzur** » Sat May 09, 2009 8:47 am

English Invader wrote:Well, that's why I'm buying it. I figured the best way to learn how a datasette operates is by buying a broken one and dissecting it. That way, if and when my own datasette is in need of repair, I'll have some idea of what to do.

huh, i could have given you several broken ones for free (or at least pay for shipping) since i threw a whole box with broken and dirty Datasettes some year ago.

why not simply make a want thread for some broken 1530's here?

hawk · Post by **hawk** » Sun May 10, 2009 7:12 pm

ral-clan wrote:I think that's why Commodore datasettes are so much more reliable than those from other systems. I always got great performance from my datasette (while computer cassette decks seem to have a bad rap among Atari & TRS-80 ownders).

I was unfortunate enough to have experienced the Atari cassette drive in it's hey day. Having the interface send data across rather than audio signal is only half of the storey.

I used to think that the reason that the Atari cassette drive was so unreliable was because it only used 1 channel of a stereo pickup head for data. This made the alignment of the head more critical, as it was narrower. The other channel could play audio during the loading process, not that I came across any software that did this.

Recently I found out that one of the more significant reason that the drives were unreliable had to do with the filters used to detect ones and zeros. Some systems used tone or no-tone to encode the data. The Atari's used two different frequency signals. If the filters used to detect each frequency overlapped too much (due to poorly selected resisters, or wide resistor tolerances) the bits could get detected incorrectly. And with no error recovery system like the Amstrad CPCs had, it was back to the begining and try again!

eslapion · Post by **eslapion** » Mon May 11, 2009 10:30 pm

English Invader wrote:If it's possible to build a new cartridge for the VIC, would it be possible to build a 1530 datasette or a 1540/1541 disk drive? Maybe even the VIC-20 itself? Certainly, it must be possible to build individual parts for the VIC and its peripherals.

Then Golan said:

gklinger wrote:Reproducing the boards isn't all that difficult but sourcing the chips, some of which are no longer made, could prove difficult. It's certainly doable though.

AFAIK, all electronic components that are on both the older 2 prong VIC and the newer rev. C (called VIC Cr by some) boards are still available and in production except for the 6560/6561 video chips.

The SRAM chips may not be in production anymore but the 2k x 8 and 1k x 4 sram chips used in VICs are still easily obtainable from Jameco and other distributors.

The 6502 and 6522 chips are still made using modern CMOS technology by the western design center.

In the datasette and 1541, ALL electronic components or equivalent are still available. The culprit there is truly the mechanical components and special RW heads. Altough in the case of the datasette, a standard portable cassette recorder's RW head and mechanism may do the job just fine.

hawk · Post by **hawk** » Tue May 12, 2009 3:25 am

If you were going to the effort of reproducing the whole hardware of the VIC-20, would you use all the individual components, having to use an FPGA for the VIC I chip, or would you just pack everything into the FPGA al la-FPGA Arcade? This would in effect make it like the C64 DTV.

I know that in our hobby, nothing has to make sense but...

Would it be possible just to come up with a FPGA plug-in replacement for the VIC-I chips? It would involve pulling most of the FPGA Arcade or C-One VIC-20 core apart and only leaving the VIC-I emulation. This would allow existing machines to be repaired. I know that I, for one, have a VIC-20 that just needs a new VIC-I chip.

carlsson · Post by **carlsson** » Tue May 12, 2009 3:31 am

Call me a nay-sayer, but I doubt those FPGA implementations are 100% complete. They may emulate most of the VIC chip according to spec, but any new cool anomalies encountered would quite likely not work as expected on a FPGA. Well, of course the implementation can be revisited and improved just like e.g. VICE is getting improved over time.

It should be quite easy to prove. Take a C-1 with the VIC-20 PAL core, load e.g. one of the latest PWP demos and see how it displays. Ideally put a real VIC-20 next to it for reference.

hawk · Post by **hawk** » Tue May 12, 2009 4:29 am

I tend to agree with you Carlsson. It would take a while to perfect all the unintentional side effects. The VICE implementation could be used to enhance the requirements beyond the original spec. I'm not sure how complete VICE is, but it plays most of the modern demos.

I'd say it's a very non-trivial task that would require someone who is both passionate about VIC-20s, and skilled at FPGA development.

English Invader · Post by **English Invader** » Wed May 13, 2009 7:29 am

The broken datasette came this morning. I opened it up and managed to fix the loose play button by pulling the metal switch forward. When I hooked it up to the VIC, it wouldn't power up. I suspect this is something to do with some loose wiring in the connector that goes in the back of the VIC; the wires are hanging out slightly.

The other notable fault with the datasette is that the black counter button has been broken off. Does anyone know if a datasette is able to function without this?

ral-clan · Post by **ral-clan** » Wed May 13, 2009 7:32 am

It should be able to function without the counter moving. I've had datasettes with stuck counters and they still worked.

orion70 · Post by **orion70** » Wed May 13, 2009 7:41 am

Wasn't there a fuse inside the VIC related to the C2N?
About the counter: I had a datassette with broken counter once, and it did work anyway.

d0c · Post by **d0c** » Wed May 13, 2009 11:19 am

the counter isnt any proplem but i guess the motor have gone to hell.... and that is when it get serious.

PaulQ · Post by **PaulQ** » Fri May 15, 2009 2:11 pm

English Invader wrote:The broken datasette came this morning. I opened it up and managed to fix the loose play button by pulling the metal switch forward. When I hooked it up to the VIC, it wouldn't power up. I suspect this is something to do with some loose wiring in the connector that goes in the back of the VIC; the wires are hanging out slightly.

The other notable fault with the datasette is that the black counter button has been broken off. Does anyone know if a datasette is able to function without this?

I had a similar problem with my Vic, but it turned out the problem was with the Vic 20's power supply. If you have a second Datasette, plug that in and see if that works. If you don't but you do have another PSU (ie; from a C64), see if that works.

IIRC, the black counter button had nothing to do with the Datasette's ability to read and write tapes; but it was immensely useful when storing multiple programs on a C60. I would record the position and program name on the case insert, so I could fast-forward to whatever program I wanted to load.

English Invader · Post by **English Invader** » Fri May 15, 2009 3:18 pm

It's definitely the datasette. The one I normally use works perfectly. This is just a broken one I picked up on e-bay to use as a guinea pig.

Pedro Lambrini · Post by **Pedro Lambrini** » Fri Jun 12, 2009 1:10 pm

If it was possible to build new Vics I would love to see a new Super Vic *starts dream sequence*... It would be in a C64c style casing but would retain the same colouring and badge (the gold one) as the original Vics and would have two top loading and one rear cart slots - all switchable. It would have a proper built-in reset button and a PSU connector on the rear (not on the side - that drives me crazy!). RAM expansion would, of course, be internal. A built-in uIEC type SD card device would be in there and it would have two auto-switching controller ports on the front. One would be for paddles and the other for a joystick. The video and audio outputs would be standard RCA connectors for convenience in replacing the leads and hooking it up to my hifi. Ooh, and a blue LED for the power indicator...

On a slightly more serious note it would be great to have new hardware so that the wiggly paddle syndrome could be cured once and for all and the video signal quality would be consistent across all machines...

PS: I intend to build something similar to what I've described above some time this year. It will be a little Heath Robinson in execution and probably not work very well but I'm going to give it a try!