Arcade Restoration - Week1: Acquisition

Wednesday Max and I went on an econoline field trip to bring back two classic cabinets in fair condition.  

I will show our restoration progress in here as time permits. Work will progress slowly since this is really a pet/coding break/lunch break project for us.

Analog TV Death toll

Its Analog TV Death Day in Canada and to celebrate here are a few personal observations.

While I sadly don't have access to any sort of statistics, just going to work each day using my bicycle I got to see lots and LOTS of Analog TVs on the curb. NO thanks to the imps at BestShop for turning customers away from the standalone ATSC->composite converters and towards new LCDs instead. "You know your TV will be dead soon" ... My dad couldn't give a rats ass about HD, while of course I do to an extent.

I bet you a hundred bux my Dad's 1988 Sony Triniton will outlast any new Chinese LCDs. Just please don't listen to the imps cause this is what happens when you do:

Ecocentre des Carrières, Montreal

As a Video Game Console turned Arcade PCB collector, I have to say that right now I'm on the lookout for good analog monitors with RGB inputs being thrown away, these really REALLY can't be replaced. You just have to be able to experience a game on the support it was built for and classic arcade PCB's output pure Analog RGB with 15KHz sync. While I have a trusty Commodore 1084 to support this format It ain't immortal so I need backups!

So the other day, going to work this scene really torn my heart apart:

Poor 1702's! They don't even have a TV TUNER! ... no RGB either, but they of course support SVideo (if you split its luma/chroma signals to separate RCA cables), and Composite. Great for any classic console. A Copper Joke ain't worth that much you scavengers!

Collectors, please stash up at least a spare analog monitor and keep it in a cool dry place, cause prices someday might make you regret you didnt.

Playing the revolution/Home Computer Invasion Documentaries in Trouble???

Original Link being gone, it makes me fear the worse.
I REALLY hope the reason isn't because of damn lawyers!

Here are two other sources for the Teasers on the most thrilling documentary series since The machine that Changed the World:








There's never been a computer documentary this well shot EVER, and nearly everyone I respect and admire in the industry took time to get interviewed. I really don't want this to be shelved.

(SAFE) US SMS Japanese Mod in action

Charles MacDonald provided a circuit for me to try
HERE

Good news is that it now works after a few treaks.
Just have to to a proper protoboard version now.

I'll be receiving two different FM Units soon, the original and the "Australian Reproduction"

The reluctant US SMS that didnt want to be japanese

EDIT2: A new solution (much more invovled ) was suggested by Charles MacDonald this will be interresting to try.

EDIT: Nice, I got my answers in that thread. I'll have to backtrack on when did this become a dangerous thing to try, FYIW I used 10k res to short pin 34.

This MOD does not work on my SMS:

I tried everything, including burning a Japanese BIOS which works great here:

While its cute and all (especially with my RGB mod to a Commodore 1084), I still don't get the mark III boot on my Wonderboy 1/2/3 carts when I ground pin 34 on 315-5216.

Another user is getting the exact same prob with this motherboard rev.

Any takes?

Does ... not ... compute...

Added Internal Picture:





Theres a piezo in there... now if I could
make it beep.....

Horrible damage due to the leaking internal soldered 2x1.5v AA batteries (removed)

The Great AdLib Fire ...

(see third capacitor from bottom) ...  I hate that smell.

From wikipedia:

"Self-destruction and thermal runaway

Tantalum capacitors are under some conditions prone to self-destruction by thermal runaway. The capacitor typically consists of a sintered tantalum sponge acting as the anode, a manganese dioxide cathode, and a dielectric layer of tantalum pentoxide created on the tantalum sponge surface by anodizing. The tantalum oxide layer may have weak spots that undergo dielectric breakdown during a voltage spike. The tantalum then comes to direct contact with manganese dioxide and the leakage current causes a local heating; a chemical reaction then produces manganese(III) oxide and regenerates (self-heals) the tantalum oxide layer.
However, if the energy dissipated at the failure point is high enough, a self-sustaining exothermic reaction may occur, similar to the thermite reaction, with tantalum as fuel and manganese dioxide as oxidizer. This can destroy the capacitor and occasionally produces smoke and possibly flame.^[3] To prevent catastrophic thermal runaway failure, auxiliary protective devices (e.g. thermal fuses, circuit breakers) may be used to limit fault currents"


Oh the joy, guess ill have to replace them and retry .. with the windows fully opened... no lets make it OUTSIDE!

Lamer Exterminator, or how a 22 year old malware can still piss you off.

As usual I need to step back for my obligatory back story.

-VIC-20 from 1981 to 1985
-C64 from 1986 to 1994 (even logged onto my University account with it!)
-Various PCs and Mac's from then on.

Didn't see the word Amiga there? Normal, only very rich kids had them where I came from. Only relatively recently did I start to indulge in that world, and what a 'fun' ride this still is. Amiga literate people can stop reading now, or continue and have a laugh at my expense...

Broadening my quest on early digital sound chips, a look at Paula (MOS8364) was inevitable, although as an 8bit DMA sample playback device, it didn't really fit the original intent of chipsounds. (no oscillators, classic samples are copyrighted, etc).

Nevertheless there are a bunch of things I plan to do following my current OCS Amiga research but I'll keep this for a series of future articles...
... So I got a bunch of gear and disks from various places.

1)Top is my ebay.co.uk bought PAL A500, which I recently upgraded and tweaked (more in a future article).
2)Middle is an Original NTSC Amiga (later re dubbed A1000), a loaner from XC3N which wasn't his in the 80's.
3)Bottom one is my most important Amiga and the first one I found in a recycling center for 20$ a few years ago: an NTSC B2000 (rev6.2a) with 1MB of chip and 2MB of 'fast/slow' ram, and a 'A2320 Display Enhancer' VGA card . This was originally a Video Toaster machine but that particular addon was already removed when I acquired it.  The most important feature of that particular Amiga for me is its generous amount of ram, since this allows transferring PC<->AMIGA floppy images transfers much easily (maybe the subject of a THIRD Amiga article)
I of course also have a weird collection of disks, some that have been recently transferred from the net, but most others are from the 'era' itself, including.... various bootlegged copies of Workbench.

Working on a complex platform that you are not familiar with is daunting for many people, but it is much more so when you get this horrible feeling that everything is flaky and unreliable. Machines that reboots randomly, Disk errors which suddenly appear on what were perfectly good disks just the day before. Since I dealt with 80s technology I just figured this was due to its age and condition...

But NO, it was ME .. the LAMER...  being exterminated!

Only this virus was made 22 years ago and it made me lose PRECIOUS RESEARCH TIME THIS YEAR, since I only figured out what was happening the day I downloaded X-Copy because of its advanced disk checking features .. or so I've read... but as I found out it also scans the boot sectors of each disks for known viruses.

This virus is apparently quite famous for Amiga people, it even has its own wikipedia page. In any case, I was quite happy to wipe all infected disks clean and redoing much of my workbench, utilities, and test disks. Yes you can laugh, but I don't recall ever getting a C64 virus in my day, so I laugh back.. boot disks .... Pffft shush...

And ... That A1000 loaner I got a month ago also came with a bunch of surprises of itself:

Yes XC3N, I've quarantined those for you for when you want to get it back.  :) Don't worry, those last ones didn't make me lose any data, I had learned my lesson by then.

Conclusion: I hate script kiddies, present and past.

patience

Oh yes I'm working on new stuff...

No updates for a while, its because I can't disclose my new stuff yet.
Sad because theres LOTS of research in there.

I'm hoping to post a glimpse at NAMM 2011.

New research on the SID ADSR

My previous post on the SID ADSR tables on the SID DIE left a question unanswered about the exact method by which the chip manages to apply the level changes in the envelopes at certain points in its decay/release stages.

Lucky for us, Frank Wolf took upon the challenge, and I'm quite priviledge to be allowed to publish his research on this blog.

So here is his analysis of that problem....

(high res)

6581 Envelope Generator (26.10.2010)
----------------------------------

In the upper part you can see the R-2R ladder; on the left is the MSB (Bit 7) of the 8 Bit counter.

Logarithmic Table
-----------------

Now take a look a the Table part! Here's the table in ASCII Form and reduced to the values on 'B' lines (please note the every second bit of the 8Bit counter is negated, i.e. the signal line is mirrored A<->B!)

B7 |B6 |B5 |B4 |B3 |B2 |B1 |B0  |Fixpoint|Signal line*
0   0   0   0   0   0   0   0     = 0x00    5
0   0   0   0   0   1   1   0     = 0x06    4
0   0   0   0   1   1   1   0     = 0x0E    3
0   0   0   1   1   0   1   0     = 0x1A    2
0   0   1   1   0   1   1   0     = 0x36    1
0   1   0   1   1   1   0   1     = 0x5D    0
1   1   1   1   1   1   1   1     = 0xFF    6

*The numbers of the signal lines have been chosen to match the numbers of the selector bits!

Every possible "Fixpoint" is compared to the 8 bit counter value keeping only one(!) of the seven signal lines "high" in case of equality. To be more exact: The lines are pulled down in case of inequality.

The 5 selector bits for the logarithmic table are generated by feeding each of the the signal lines 0 to 4 into a simple flip-flop to "set" it. Output of the flip-flops is active "low"!) Additionally both adjacent signal lines are also fed into the flip-flip to "reset" it; resulting in a "high" level output.


Example:

Selector bit|
Signal line | "Reset" signal lines
0             1, 6
1             0, 2
2             1, 3
3             2, 4
4             3, 5

Sustain value
-------------

The 4 bits from the sustain value register are connected to:

Sustain bit 0 to Counter bit compare 0 + 4
Sustain bit 1 to Counter bit compare 1 + 5
Sustain bit 2 to Counter bit compare 2 + 6
Sustain bit 3 to Counter bit compare 3 + 7

So they are (as already known and verified through tests) compared like:

0x0 (S) == 0x00 (Cnt)
0x1 (S) == 0x11 (Cnt)
0x2 (S) == 0x22 (Cnt)
.
.
.
0xE (S) == 0xEE (Cnt)
0xF (S) == 0xFF (Cnt)

Plogue chipsounds running on VMachine Hardware