Let's Asterock around the clock !

[level42]

Looks like everybody is sunbathing in North West Europe....no activity here....

Found a great spot in the backyard in the shadow to work on the Asterock.

First thing I noticed when I powered up: no neck-glow, but I hear some fine deflection shatter ! This would indicate that the game was running !

Cool !

Now, why no neck-glow ? That was easily found out. Turns out the 6.3 VAC comes straight from the power supply. No 6.3 VAC there....mmmm, check schematic....HUH ? There's no fuse in the holder for that voltage, but there _is_ one in an unused section of the PSU. So probably put back in the wrong spot. Changed it over and Hurray, we have neck-glow but........no more deflection shatter ! (Boo-hoo) Spot killer LED is on, so there's something wrong with the input signals probably (probably game PCB not running).
Checking all the basics first, I found out that the -5V is too low (high ?) at -2,2V. Now gonna check if it's the 7905 on the "AR2" board or that it's simply overloaded by something on the game PCB....

To be continued !

[kroustibat]

way to go andre 

i wish i was sunbathing,  i just finish to mown my lawn. totaly tired now

[level42]

Had to dig deep, but I found a spare 7905. I LOVE to have some stock !



My son assisted once again in this hobby:



I thought the problem was the monitor at first so I had removed some parts to get it out:




Some Italian factory worker had a sunny day as well, this is the monitor shelf, gotta fix that !:


The G05-802. With ORIGINAL Atari part.nr. label, I still can't believe it


I know you guys like dirty pics, so here are a couple:


HV-cage:



Sooooooooooo, after checking my son's soldering (which I have to say was simply perfect, didn't have to do anything about it !) I put everything back in place and fired up.

HA I had neck-glow AND deflection chatter sound !!! This was promissing. Went to the front and was disappointed. There were just some tiny lines on the screen in the center....o no.....

but then I thought this might be the test-screen in low brightness......soooooo I flicked the test-switch and turned up contrast and brightness and........

http://youtu.be/ImOo-Zdzo-s



WAAAAAHHOOOOOOOOOO !!!!

[Belike]

Looks very promising.

[level42]

Yes, one more game running for Eurocade !!! I must say I already like the set-up of the control panel A LOT. I think this is actually probably more comfortable than Atari's bulky panel !

Now, I'm not sure, but I think the firing sounds is not correct. Not sure of course, since this is a bootleg, but all the other sounds seem to be very close to the original (the speaker is messing up a bit, sounds resonating, maybe I'll need a new speaker) but that shooting sound is annoying like hell.

Anyway, big THANK YOU to Speleo who fixed this board for me !

When I had checked the old 7905 running without load, it went up to -13Volts !!! So I was very sure it was bust. Credits to the designers of the 78xx and 79xx series making it so safe, because even though it went bust, it still protected it's output voltage so nothing got damaged. I didn't know what the -5V was used for. It runs through a separate cable (together with a +12V to the backside of the board. Turns out it runs to all the 2708 (!) EPROMS there. So good thing these weren't damaged !!

[italiandoh]

Glad to see another one up & running !
Congrats about the fix 

Matteo

[Superully]

nice fix, andré! and while i'm getting better with electronics, i'm still far behind you. my problem is that i simply don't UNDERSTAND how those games operate and therefore don't know what to check - hopefully i'll get there eventually. what i DO like is how you "integrate" your son into your hobby - must be the coolest feeling in the world!

[liquidx]

Now, I'm not sure, but I think the firing sounds is not correct. Not sure of course, since this is a bootleg, but all the other sounds seem to be very close to the original (the speaker is messing up a bit, sounds resonating, maybe I'll need a new speaker) but that shooting sound is annoying like hell.

Doesn't sound right to me on the video either. Then again, maybe the bootleg has its own.

If I remember correctly every sound has its own circuit on Asteroids so it's relatively easy to isolate the problem area and trace through it. I had a similar problem with the fire sound and had to replace a small IC in that circuit.

If I also remember correctly, all the sounds are generated from the clock signal so tend to vary from one machine to another also along with the little voltage differences.


Looks cool though.

[Etienne MacGyver]

Yes ! , congrats on the fix !

I like it too that you drag your son into the techie things  

My idea is the same, but mine is a bit younger though... so i dont handle him the solderstation just yet  
But as long as they learn from it, its ok

you cannot start young enough to learn stuff imho

[Q*ris]

If I wear shorts and walk on my knees would you incorporate me in your restos and teach me a bit of electronic/soldering too?
Honestly it's really hard for me to understand half of what you're doing here but this is still really interesting to read.
Must be an awesome feeling to locate the problem, fix it and finally get the machine to run!
Can't wait to play this game and compare it to Asteroids (already noticed that the small ships are 'only' worth 500points in this version).

[DarthNuno]

Congratulation... to your son   

[level42]

Thanks guys, I will comment more a bit later, but for the Asteroids experts they should already have seen (I mean heard) one more defect:

The enemy saucers fire sound doesn't work......

[level42]

Arrghhh.....I just checked and compared the original Asteroids schematics with the Asterock schematics.

Results:

1)
The 555 pin 3 that is connected to a capacitor and resistor which "unloads" during the sound, and thus reduces amplitude and frequency of the fire sound (see explanation on Atari Asteroids schematic) is simply omitted on Asterock. Hence the irritating BEEEEEP at a constant frequency and amplitude. It annoys me greatly. Not just that it's different, it's really a quite loud sound compared to the thump sound. Not sure if it's possible but I think I'll try to add some RC combo to recreate the original sound....even though, technically, that is _not_ original for AsterOCK.....

Original Atari Asteroids, see the parts encircled:


Asterock, nothing at pin 3 !:





2) from the LS259 Latch that triggers the sounds, pin nr. 5 (SAUCRFIREEN, which means Saucer Fire Enable) is not hooked up to anything on Asterock !!!! I guess they tried to make the game "different" from the original that way. Anyway, there should be an identical 555 set-up behind that output to create the Saucer fire sounds (with different RC values so that  the sound is different from the Ship (your ship) sound......

Original Atari Asteroids:


Asterock, notice pin 5.....nothing connected, nothing indicated.....



Could try to add that, but I first will have to measure to see if that output on the latch is actually activated when a Saucer comes in and fires shots.

Anyway, this means that the Asterock is actually working 100% at the monent (I thought that maybe a Capacitor was bad or missing for the Ship Fire sound....but it's intended this way by Sidam...

Nice to puzzle this out tomorrow !

[level42]

Just checked Asterock in MAME. The sound emulation in MAME is wrong for this game, since it DOES have the decrease in frequency (Piiieeeeuuuuwww) and Amplitude for the ship firing sound, and the saucers shots are also producing sound. Quite simply incorrect !

The good thing is that it's very likely the Asterock ROMS DO trigger these sounds....more tomorrow

[Etienne MacGyver]

Now thats a nice game of "find the differences"

thisone is more interesting than one of these: