Is R12 brown,black,red or brown,black,orange? Is R7 red,violet,orange, or red,violet,brown (orange makes it sound bad) What are the colors on C6? brown,black,orange? Or is that backwards? Is C5 100nf like C3? Are the diodes 1N4002? I don't think this one matters much. ...
R12 on my Trinitron looks brown,black,orange,gold. R7 is red,violet,red,gold. C5 seems to be printed "104M" which is likely 100nF.
C6 looks brown,black,orange,dark blue(???),grey on pink background material. The ring near grey may be also brown or black or dark violet, but it has a different hue than the given brown and black ring of that component. I have several photos of it, but it is dark and shimmers differently on all of them. It is darker than other such rings and might be simply black and shows a hue due to reflected light by the different angle of the bulged package shape.
I did not examine the diodes; they are hard to see without desoldering and likely plain silicon. On D3 I see "400..." On D4 I see a "2" near the ring and a "4" in the 2nd row. (Strange is that many parts have stray solder blobs on top like when a previous owner had soldered at them too.)
Regard that the volume envelope duration (point where decay falls silent) differs with battery voltage. They are 5x 1.5V, so maximum +7.5V (unpleasantly loud, long decay) but it works well below 5V (shorter decay, noise waveforms a bit weaker?).
There's another handheld that needs netlist sound, Coleco Galaxian. It has a sound effect when an enemy dives down. Kevtris made photos of the PCB but one capacitor is hiding in the photo, and some resistor color bands are hard to see. It also has a weird "PUT" transistor that I don't think MAME supports.
Is it a sawtooth generator like this, or the other (sine?) oscillator?
- power on - synth mode - press a note key (resets parameters) - F12C - play keys EDCBA - F30C - play keys EDCBA
Which one sounds more like the real one? I don't mean the pitch or the decay rate, but the buzz in the background, especially on F30C with R7=2.7K.
Youtube video of Coleco Galaxian, fast foward to 2:30 Sound is too high pitch for me to determine by ear if it's a saw wave. And I don't really care what the exact waveform is, just that it's not simple enough to simulate accurately without a netlist in MAME.
In the original the buzzing bass subvoice is definitely stronger than in both your examples. It is more a bit like a slapbass or plucked ruler humming in the background (or a low organ footage). But that is also because your pitch (clock rate) is 1 note too high (your "D" note is my "E", so I can't reach your "E").
Your sfx_r7_2700.wav example sounds closer, but R7 definitely is red-violet-red-gold.
With the Coleco Galaxian tabletop I suspect that they used a VCO with analogue fixed falling pitch envelope generator because the chip would have been incapable to compute the stepless howl without wasting too much CPU time.
And one thing that is more interesting: https://www.handheldmuseum.com/Bandai/Galaxian.htm There are 2 versions. One that has the Star Wars jingle at start, and one that has a jingle that sounds like Namco's Galaxian arcade. The 1st version(Star Wars I think) is on a NEC D553 MCU. So if your MCU note is correct, they ported the game over to NEC D7502G to just change the startup jingle.
Hmm, no, unfortunately I don't have a better pic of that U-Boat... I might still have a loose one of those though, if I come across it I'll check it out (and send it for dumping if needed). There's a dirt cheap one on eBay, but it's located in Egypt, so shipping is nearly twice the bid price.
Agree on Battle Beam, definitely the Japanese Flight Time.
And didn't know there was a difference in Bandai Galaxian. Next time I'm in storage, I'll check and see if I have a loose one. I know I have a Block Out still, but not sure about the Galaxian one... Do we have that first version dumped in MAME? I need to create my 'handheld only' build again. Last time I looked at the source code it had changed a lot (all of the drivers have been resorted into different directories or something), so I just kind of went on to something else.
I wish I had taken more 'guts' pictures with my real camera before I sold everything. Most of them on that guts page where taken with an old 1 or 2mp camera, so they kind of suck...
Tryom Gammonmaster II from 1978, dumped by Sean. Is this considered a handheld or a more specific 'backgammon computer' category like chesscomputers are? Not that it matters for MAME since it'll go into the tryom folder.