flip
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Posts posted by flip
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Oh I do have one more question. I have been turning off the console, unplugging the power supply and removing the multicart after I'm done. But I was wondering, would it be okay to just leave the multi-cart in the console? I don't have any original carts yet so I'm not going to be plugging in any other carts any time soon. But I wanted to check in and see if there is any potential to do damage by doing that given the age of the console. Thank you!
sorry, missed the question here...
Leaving the multicart in should be fine - in fact, given the age of the connector, it's probably best to pulg and unplug as little as possible. in addition, leaving a cart in protects the connector from dirt and what have getting in.
FliP
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All interesting. What are the actual changes tho from Rev C to Rev D?
Can't see any obvious changes in the main logic: all the chips are the same (unlike the change from D->E) - haven't looked at the RF circuit yet...
FliP
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Sorry for the double post but I was quickly looking at that "RCA Studio II teardown" on ifixit and noticed that the serial # on the unit he opens is #131. Then I looked at the board where it shows which revision it is and it -is- a C (unless I am mistaken). So this unit is very likely to be a revision C board.
Here's some photos of the #155 console. The serial number on the outside matches the one written on the board. More importantly, it IS a revision C board as suspected by TLD1985!
The warranty sticker (still sealed until this afternoon!) mentions the year 1976, as do some date codes on some of the chips: the CPU suggest week 45 in 1976... The CPU, ROMs and video chip are white ceramics, which looks really quite fragile.
The ROMs result in the same checksum and part numbers as the other boards, meaning that the on board firmware wasn't changed or updated along the way, unlike the hardware design.
FliP
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Did you guys see the work of SlyDC?
http://rcastudio2.blogspot.ca/2017/01/chip-8-for-rca-studio-ii.html
Interesting... inserting the multicart (or any other cart) disables 2 of the 4 roms in the console. The lower ROM with the interpreter and interrupt routines remains active between $000 and $3FF. It can easily be disabled however by connecting the ROMDIS signal to all four ROMS. The multicart has a jumper, which maps the range between $000-$7FF and $C00-$FFF to the multicart. You could put your own code in one of the slots and run a custom version of CHIP-8 I think, as long as you correctly map to the 512 bytes of RAM (between $800 and $9FF, which is hard coded).
At a push, a cart could be developed that has up to 64k available, though you'd still be stuck with a limited amount of RAM: the /MWR signal is not available on the cartridge slot, so you're stuck with read only memory on the cartridge... Some of the bigger games use video page caching to speed things up - that would probably be impossible to do on the RCA Studio II.
FliP
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I do wonder if they decided against adding any beeps/whines to not deter sales (or even stop shops going insane from hearing it 1000s of times a day in its short loop)
While the sounds wasn't going to impress anyone, I doubt they were concerned about the sanity of store clerks. The sound can be switched off via one of the switches on the bottom, in case it would drive someone in the shop nuts... More likely they had to economise space on the cart: the title screen alone takes 1/4 of the available space. And there's 6 text lines, which would be at least another 1/4. Looking at the dump, they had about 320 bytes to code the rest... The rest seems to be graphical data.
FliP
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I tried the rom in Emma02 and it worked perfectly in both the StudioII emulation and Victory MPT-02 emulation.
Yeah - my bad. I had loaded the victory rom in the Studio II emulator, so that doesn't work properly... Nothing to do with the Demo Cart (duh!)
FliP
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Hi all,
Thanks for the efforts of someone who wishes to remain anonymous and stupus, we now have a dump of the RCA Studio II Demonstration Cartridge!
The updated image for the multicart can be found here. The demo cart is in slot 0-F (so the left dial on 0 and the right dial on F)
The .st2 file for the emma02 emulator is attached... One thing i've noticed is that the cart doesn't seem to work correctly with the emulated clones (MPT-02, Victory, ...). I need to try this on a real machine, but haven't gotten around to that.
Since most people won't be able to re-flash the chip on their multicart, several people have offered to help out with that. ekeefe and KylJoy are both in North America, which should speed things up a bit... If there's more, then feel free to let people know.
Rather than sending the entire cart around, people should be able to gently pry the square chip (marked 39sf040) out of the socket and post only that... We could also set up a sort of carousel: if I send a few people new chips, they could send the old one in so they can be updated and sent to others?
Enjoy,
FliP
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Can someone post a pic of what a disassembled RCA cart looks like, I'm assuming you end up with two pieces and the board? We just ordered a hi res 3d Scanner at work to go with our two 3d printers, it might be worth trying to scan/cleanup and print. We've been experimenting with Acetone bath cleanup to remove the visible layering effect and are getting some great results
Here's pictures of the opened cartridge.
FliP
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I definitely agree though these repros need some amount of designation to distinguish them as repros.
A happy medium just needs to be found where they can be easily identified as fake, yet not detract any more than needed from the design.
I think we can leave the shell/label as original as possible, but have the PCB different enough to distinguish them either in color (the current set is red which was never used for real carts). We could also add some silkscreen message to indicate a repro on the part sticking out. That would make it harder to cheat while looking the part when it's in the console...
also: all the repro ideas are nice, but I guess there's a limited number of shells... Unless we find a new source (i.e. commission a new production run), there's not going to be more than a few dozen? It would be a shame to sacrifice working original carts for repros.
FliP
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Hi,
The first batch of multicarts (about 40, including some complementary ones) is all gone. I need to re-order the PCBs, which I will do in bulk as soon as I've done some testing with an updated design. I post here when they are available again, but it will probably be mid-February...
FliP
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Quick and dirty attempt: https://goo.gl/forms/yiYXzYqoryasF5A73
To be clear: the most interesting would be the serial number written/stuck on the PCB - meaning the console needs to be opened. While the numbers on the console shell/box/PCB seem to match for early and late production systems, that doesn't seem to be the case for most Studio IIs I've come across...
The results are here: https://docs.google.com/spreadsheets/d/1XBAsnVxHJ_Q2bkE02U74nG3c8W2KhculCUdPljC2B0M/edit?usp=sharing
If you prefer not to open your console, no worries... Main aim is to get an idea of how many of the different revisions were made...
FliP
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Sorry for the double post but I was quickly looking at that "RCA Studio II teardown" on ifixit and noticed that the serial # on the unit he opens is #131. Then I looked at the board where it shows which revision it is and it -is- a C (unless I am mistaken). So this unit is very likely to be a revision C board.
Good find! Hadn't noticed this before... The earliest board I've seen is #1345, which is a revision D. So that suggests the switch from C to D was made very early on in the production. Comparing the iFixit board, I can't see any obvious electronic differences to the revision D in the main logic (at least not like the difference between D & E).
The highest D I've come across is #10,929. This appears to be a replacement PCB for technical interventions (i.e. it didn't come in a case). It's guesswork, but it could mean that 1000 revision Cs were made, then 10000 revision Ds and the rest were Es (up into the 150,000s).
Perhaps we need a serial number DB? If there's interest, I can set one in in google sheets/forms?
FliP
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Thank you! And no worries, I decided it would only be fair that I bother everyone else on the thread and not just you.
Thank you for the tip on the serial number as I have no clue how to determine which board I have. Also what does the jumper look like? I'm just wondering if it's something that'll be obvious to me when I open it or if I need to poke around. I'll try the RAM test a few times, did it about twice and it passed each time, all the tests seemed fine. The image is great actually, even on an LCD, crystal clear. And it is odd that it's inconsistent. I can play Pac-Man fine, he moves in all directions, no glitches, yet Space Invaders without fail the ship just doesn't move, unless I wipe the contacts with alcohol or an air can on the cartridge port, then it moves a bit and locks up again. But it's odd that other games are fine. I'll open it up and see what I cna do with my limited skills.
Just to make sure: the jumper is on the multicart - not inside the console... It has a yellow square on the attached photo. Just move the jumper so the left two pins are connected instead of the two pins on the right...
FliP
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Ah okay. So I'll take the cart out of the case and see about these jumpers. And I'll open up the console to see if I can determine which board I have. Thanks for your help!
Sorry - I was away for a few days and traveling all day today.
Revision Ds have a low serial number, probably lower than 10,000, but I don't think the board revision should matter on an actual Studio II, though it doesn't hurt to try. Move J-2 to the 1-2 position and see whether this makes any difference...
It's very odd that cleaning the slot would offer a temporary solution, let alone that some games seem to work. Every time I've seen such behaviour, i've traced it to one or more RAM chips behaving badly. You could try running the RAM test several times to see whether it trips up... Failing that, It might be a timing issue, whereby the oscillator that generates the clock is no longer tuned correctly. That *could* throw the TPA circuit on the cartridge off - but that a long shot, especially if you're getting a good image on the screen...
FliP
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Flip is sending me a cart without a shell. Very excited. I plan to take apart one of my other cartridges as a donor shell for this, but my question is what is the easiest way to take these cartridges apart? I've taken apart dozens of Commodore cartridges (C64 and VIC-20) which are held together with screws and plastic tabs. Studio II cartridges, on the other hand, appear to be held together with rivets. I don't see an obvious way of taking it apart without damaging the cartridge. Is there something I am missing?
The 4 copper rivets need to be drilled out. Don't think there's any other way to take them out. If you take a drill that slightly wider than the rivet hole, it's not too hard and there shouldn't be any damage to the shell itself.
Once they're out, take out the old PCB, clean off the stickers and put the new ones on. Then you'll need to drill two holes for the dials and put the shell together again... In the shells that I modified, I re-used two rivets. I glued these in the top holes. For the bottom ones, I used a copper screw thread insert (see photo) that just fits the hole left by the rivet and a matching screw. That way, the cart can be opened without needing holes in the stickers...
FliP
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Here you go - page order is a bit funny, for printing reasons, so watch the page numbers on the bottom to make sense of it...
FliP
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Phew - you had me worried there for a while
On the Studio II, the cart works with the default setting. If you have an earlier board (Rev D), you can set J2 to position 1-2 (instead of the default 2-3). This bypasses Ed Keefe's TPA circuit that re-creates the full TPA signal on the cart. Without this circuit, the revision E boards seem to mirror the higher address ranges to the lower ones. This is described in Paul Robson technical pages. I can't think of any reason why RCA designers would have done this: it effectively limits the usable address space to $400-$7FF...
On the clones, I suspect that the timing is slightly different, so that the TPA circuit struggles with keeping things in sync. I've not looked with a logic analyser, but since bypassing the circuit works, it's not something to worry about.
In short:
RCA Studio II, revision D: J2 1-2 or 2-3 shouldn't matter
RCA Studio II, revision E: J2 must be in position 2-3 (as is on delivery)
Clones, including Conic and MPT: J2 must be in position 1-2
FliP
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Great to hear you got yours already!
For the Conic and the other PAL clones, try to set jumper 2 (the one on the right when looking at the component side) to the other position: short pins 1 & 2. I think the TPA signal is not crippled like it is on the Studio II, so the circuit can be bypassed...
The rotary switches: they do have a distinct top that points at what is selected, but it's hard to see... The EEPROM only has 128 slots, so selecting 8-F on the left dial is the same as using 0-F
Quite a few games, old and new, require you to press something before they start...
FliP
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Once my package arrives, I'll open up my Conic M1200 and compare with the pictures of a genuine Studio II, if it has the same soldering points. Of course it already takes 9V DC so no need to modify that part, just install the composite video board. Is the signal you tap already a weak composite-ish signal that the board amplifies, and in that case could it be used as a basis for amplifying similar signals on other systems? I suppose component values may need to be adjusted based on the original signal strength.
I can guarantee that that won't work. The video circuit of the color/PAL clones is very different from the RCA Studio II. You can get a monochrome output easily enough (even without any composite mod) but to mix in the colors is trickier. I have a basic circuit working, but it's rather tricky to install as the RF board needs to come out to reach a trace on the underside. I think I might use the reference design on the datasheet of the CDP1864 to design an independent composite or S-video signal, but no concrete plans yet...
An added complication for those consoles is that there's no onboard speaker: the sound is also mixed into the RF signal... It's not a biggie, but a second connection is needed to connect the sound to a line in/amplifier...
FliP
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Hi all,
Attached is a manual on how to install the composite out mod in your Studio II. Please have a look and let me know if there's any questions...
Most carts are on their way, or will be on their way tomorrow. I had to repackage some as there's restrictions on how tick the package can be - Anything above 3cm would cost about 3 times more in shipping: I had to take the PCBs out of the shells to get the the padded envelope under 3 cm
The shells have been modified a bit: to open them, the rivets had to be drilled out. The bottom two have been replaced with screws. On top, 2 half rivets were used to keep the shell together. That way, the labels don't need to be damaged if ever you need to re-open the shell...
When opening them, make sure you pull it open 'evenly' so you don't bend the rivets. If it's stuck, try prying it open with a knife or other flat tool, making sure you open it evenly on all side...
Let me know when you receive your cart!
FliP
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I'm interested in the multicart and composite out board, although I didn't see any pricing or what installation of the composite out board involves. Is there info I'm missing outside of the post #1?
Hey Bill,
I can't send a private message to you for some reason... Can you look into that or try to send me a PM?
Cheers,
FliP
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If it's not too late I'd love a multicart, shell, and mod board too!
I am out of shells, but I can get you a cart, manual, stickers and a composite board...
FliP
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Hiya,
No bother - things were a bit slower than anticipated: I wasn't planning to make labels & manuals, but I got lured into doing just that... Manuals arrived on wednesday and I got the front labels today. Stupus did a great job designing these, so all praise to him! The only slight concern is that the colors are a bit off: I used a different printing service, and they couldn't reproduce the 'radioactive' green that Stupus had chosen... So the greens are a bit different, but I'll make sure that the front and the back label are at least the same....
We also have the final ROM, so the carts themselves are ready. I still need to build around 10 composite boards, which oddly enough take nearly as long as the entire cartridge...
I'll probably start sending out PMs this weekend, so watch you're inbox...
FliP
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Thanks for the info, i must have crap in my eyes not seeing (errr...reading) in the first post....think i'm getting too old.
At $40 (cart+shipping), it's a great deal so put my name on the list too. Now, it only missing a front and a back label
for those who's going to get a shell with it. Anyone up to designing those labels ?
Like this guy (Nishikintoki) on DeviantArt who made a front label and the box cover of a fan-made (non-existant) game
called "Race of Speed". Check out the two links:
http://nishikintoki.deviantart.com/art/Race-of-Speed-Studio-II-625633565
http://nishikintoki.deviantart.com/art/Race-of-Speed-Cartridge-Studio-II-1977-625634601
Stupus has kindly offered to take on the artwork... He should have something to show soon (though I need to send him some measurements).
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RCA Studio II GOLD MINE! An interview with the Studio 2 Production Manager!
in Classic Console Discussion
Posted · Edited by flip
Hi,
The memory diagnostics write to the color ram - on a B/W, this doesn't do anything, but on a color one, it produces a nice test pattern. It only shows towards the end of the test, but running it again has all the pretty colors!
Attached is the st2 of my diagnostics - press 2 to run the memory test in a Victory machine and after a while you'll see colors. Background doesn't change, but I guess that could be added...
FliP
test.st2.zip