Zaccaria Space Pirate arcade repair. Mistakes happen!

[@rapiqui]

Woah! I am speachless. Great job! I had even saw some demos on oscilloscopes, but using it as a vector monitor was brilliant. Super instructive as always. Big thanks for this fun time!

[@iz8dwf]

Hi! Actually the oscilloscope is a great XY monitor, however it's not straightforward to use the Z (brightness) signal from the game boards, so everything is "connected" by tracing lines. It's a bit too tiny if you don't know how the game should look like (and I surely didn't know it). So I've used a "real" arcade vector monitor :)

[@Shmbler]

What an interesting failure mode of this cap! There's always something new to learn in your videos. Thanks!

[@iz8dwf]

Hi! I'm glad you liked it! Thanks!

[@RavenWolfRetroTech]

Love it! Another machine brought back to life and an interesting puzzle too!

[@iz8dwf]

Hi! Thanks! These games are not very common either :)

[@patzik1910]

Repairing the analogue section is always hard for me, I am amazed by your detailed knowledge and troubleshooting skills. Great video again and interesting game, does it really have no cpu? I repaired a pong board recently, and was fascinated how Woz designed this with only ttl logic ic's but this looks impressive too.

[@iz8dwf]

Thank you for the nice comment! These games don't have an integrated CPU (the ones on a single chip). The engineers built a CPU using integrated ALUs (3x), TTL registers, rams and proms. So it does have a CPU that can excute code but it's a custom design.

[@marcopantanetti4053]

Well done Francesco, never seen this game before, thanks for sharing.

[@iz8dwf]

Grazie Marco!

[@petesapwell]

What a strange little game, never heard or seen this one before. So no actual CPU just discrete, are they implementing a state machine like Atari did for Asteriods et al? That little tantalum gave you a run around didn’t it :)

[@iz8dwf]

Hi Pete! Well actually they implemented a quite complete CPU. As for the vector generator, they made a really clever "analog vector machine" to offload the vector drawing from the CPU. Basically the CPU just writes the start and stop coordinates for any line to be drawn, then an analog opamp circuit makes the actual line by charging a couple of capacitors at constant current between the start point and the end point. And yes, that tantalum really took me for a ride. I can't believe they couldn't make it with the correct polarity!

[@petesapwell]

Hi Frank! That’s fascinating architecture!! I imagine those caps in the analog vector section are high quality! Will have to look this one up for a gaze over the schematic, I’ve still to revisit the Zacharia Invaders board, so many board sets in for repair atm, I decided to put it aside for a while, has sound issues still.

[@senilyDeluxe]

I think the architecture is at least inspired by the PDP-8 which also was12 bits and later variants used the 74181 ALU as well. But yeah - not too many arcade machines with 12 bit CPUs out there.

[@iz8dwf]

@@senilyDeluxe Hi! Very interesting indeed. I didn't think about the pdp-8 but might be inspired by it. I like very much various solutions that Cinematronics' designers employed in these old machines, like the very peculiar and clever "analog" vector generator. They could make an "asteroids" like game with less ICs and less complexity than the Atari design.

[@deborahberi3249]

Never realized the Pirate market ever existed in this area! -Mark.

[@douro20]

Interesting to see a Yugoslavian capacitor in there.

[@iz8dwf]

Hi! Do you mean the one I've substituted? In the '70s and '80s in Italy we had many different sources of electronic parts. Of course we had our own manufacturers for both passive components and semiconductors, but it was common to find soviet resistors for example and some other eastern countries' passive parts. Semiconductors were only Italian and western countries' as far as I recall.

[@douro20]

@@iz8dwf Yes, that electrolytic capacitor had the Iskra name on it.

[@iz8dwf]

@@douro20 thanks for noticing it! As I said italian manufacturers had many sources for passive components from a good number of different countries.

[@danielepatane3841]

Buona sera, is there a way to get in contact with you via email Sir? I need to know some info on an old hp instrument. Very respectful Daniele

[@iz8dwf]

Sure, my email address can be found in the youtube channel page, but here it is: [e-mail]

[@danielepatane3841]

​@@iz8dwf grazie molte, le scrivero più tardi perché adesso sono a lavoro.