Description of my modified "Games-Library" VCS2600. 2000-04-11 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I have a VCS clone("Television Computer System") which originally contained 128 built-in games;I have modified it with an binary LED chain game number counter and the ROMs of the(in Germany very common) Atari 32 games cart and the 128 games ROM from a second singlechip VCS-clone(which damages carts), though it now contains true 288 games(as the lying frontpanel-text of that china-thing claimed before).The bad things is that many of these games are originally NTSC versions those produce very ugly colors(some just flicker B/W) on my PAL VCS.(I mounted an auxilary colour adjustment potentiometer on the back,but this makes the colours just less ugly,but not correct.) On the havily modified VCS I have glued onto the(originally plain black) front panel a sort of hologram foil that shines in bluish/greenish(and a bit redish) rainbow-like horizontal stripes - IMO the only appropriate colour really sui- ted for a VCS2600.In the center of this I glued a part of mirror foil with a vertical,green LED line displaying the selected game number in binary code.The front part of the case socket(i.e. below the front panel) I also equipped with this mirror foil and placed a huge LED in the center which is either lit in red,yellow or green to display which ROM bank is actually selected.(It goes off when a cart is inserted.) Onto this mirror foil I wrote in blue letters "Games - Library".(Also the LED chain has small blue numbers left and right next to it to show the binary values of the LEDs.) hologram foil mirror foil and LEDs hologram foil | | | v v v ___________________________________________________________ \\ \ : / // \\ \ : / // \\_____________________\___:___/_____________________// ~~~\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/~~~ \ Games (O) Library / <- mirror foil =--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--= Before you come in mind to buy a bootleg VCS2600 I first have a serious reason to warn you! If you ever find a bootleg 2600 that contains only 2 big chips (game ROM and CPU),then NEVER put real carts into its slot,because it seems to destroy them by using a too high clock frequency on it's multiplexed joystick- /databus.When I played my "Centipede" cart on it,the copyright sign on the screen became garbled(pixel mess).When I put the cart back into the real VCS, the sign remained garbled for several minutes until it slowly returned to its normal state.With my "Decathlon" cart I discovered the same phenomenon,though I refused to test any further carts in it.Instead I prefered to desolder its 128 games ROM to add it to my other 128 games VCS which is based on real VCS chips.This other VCS I have tuned by wiring it's non-connected paddle ports to the appropriate pins of the chips and 4 capacitors,and I added the missing co- lor-B/W switch,though I got a fully operable VCS2600 containing 3 ROMs with together 288 games.To select them I connected an LED chain to its adress deco- der so I can read the game number in binary digits when I swith through the 3 game-banks with the build-in adress counter IC. The dangerous VCS clone that kills carts(only EPROMs?) looks like the old 4-switch VCS,but it has no wood design on its frontside(just black) and the switch-panel with the writing on it is colored silverish.It contains 128 games built-in,although a bigger amount(512?) is written on a label.Inter- nally it contains only 2 ICs on a very small PCB.This VCS is also not very compatible(e.g. my Pitfall II cart did't work),though it only should be used to play the built-in games.Used for only this purpose the device makes even a much clearer picture than any real VCS I ever saw,but I just wrecked mine of these dangerous things to get it's game ROM. Sam. wrote: [on rec.games.video.classic] > > CYBERYOGI =CO= Windler wrote: > > >And I also have a reason to warn you;if you ever find a bootleged VCS2600 > >that contains only 2 big chips(game-ROM and CPU) > > Any idea how these work, and where they came from? Presumably the > TV-Boy is one of these. Where are the TIA and RIOT, etc? In the CPU or > the ROM? Is the CPU a ULA, or have they been manufactured specifically > in some factory somewhere, and can you get the parts? > The ROM is an ordinary 1MB ROM with 128 8k games(I soldered it onto the ROM of my other,usual designed 128 games VCS(TIA,CPU and PIA have just unusual num- bers),where it still works fine. The other chip(40 pins?) uses a wierd multiplexing between data bus and both joystick ports via diodes(a "wired OR") and switches their GND lines to select between the 2 ports.By this reason the ports can't be programmed as output li- nes(and won't work with auto-fire joysticks etc.???) and there is no pin on the chip to connect paddles to.I guess to perform this switching between data bus and the 2 joysticks fast enough,it tortures the carts with an asymmetric, at least 3 times too high clock frequency and though probably erases(???) their ROM contents.(As far I know,the EPROM write line of any carts aren't connected to the cart port,though the phenomene of changing a cart's ROM con- tents can't be caused by any "regular" ways.) > I'm wondering, because a 1-chip 2600 would be extremely cool, you > could build it into all sorts of things, maybe one of those LCD TVs, > and you could burn your own EPROMs and plug them into a ZIF socket. > You could also maybe give it a cart slot, which is the one thing the > TV Boy really needs, if there were some carts (Common ones you don't > mind losing) that would work. > I still have the PCB(in Germany...) and the CPU chip has ca. the size of a Z80 CPU(no tiny SMD part that fits into an LCD TV.).By well known reasons I really can't recommend to equipe a game with this CPU(TV-Boy?) with a cart port. The safe VCS clone that doesn't destroy carts looks also like a 4-switch 2600, but has a black switch panel and my was labeled "Television Computer System(?) 288 built-in".Internally it contains a circuitry similar to a the real Atari VCS2600.The only differences are:it has no shieldings,the ICs have different numbers,the paddle-port is not connected and the color-B/W switch is missing. Also the 7805 voltage regulator has no heatsink,so it gets very hot.(This must urgently be fixed manually to avoid frying it!) With paddle port and B/W- switch fixed,this device becomes a 100% compatible VCS2600.(It even works to- gether with my lovely music playing ancient "Compumate" computer keyboard!) Later when on this console I wanted to show the musics of my "Compumate" com- puter keyboard to someone,I sadly discovered that it started to make character mess instead of BASIC commands(eg. "PrIf" instead of "Prt") and in the paint program the cursor had become a grey vertical bar while the left side of the graphics was messed up.Though I tried my Compumate on 2 different 2600s and my 7800 and on all of them it worked fine.Though I angriely read some VCS FAQs and decided to take my "Games-Library" apart to find the fault.During this proce- dure I socketed PIA,CPU and TIA and exchanged them with parts from other 2600s - with no success. :< Then I messured the voltage on the cart port and surprisingly recognized that the Compumate(consumes around 75mA,i.e. more than ordinary carts) got only 4.1V instead of 5V.I analyzed the circuitry and found out that the hardware of my 2600 clone drew the current to the cart port through a very tiny,cheap sili- con diode and amplified the voltage drop on it by some transistors to determine whether a cartridge is inserted to activate the chip_select line of the inter- nal game ROM in the case of none.Unfortunately the voltage drop on this tiny diode had become so large that my Compumate had stopped working.After repla- cing the diode with a bigger low-drop silicon type,the Compumate got 4.31V and worked again,but still made some minor pixel mess until it warmed up en- tirely.The next day I desoldered an old germanium diode from old TV parts (which made an even lower voltage drop) and after soldering this one parallel to my silicon diode(to protect the germanium from too high currents) into the VCS,now the Compumate gets ca. 4.44V and after some seconds of warming up it is now virtually free of any pixel mess. (During experiments I found out that touching a pin of the TIA(Ready?,HALT?) with a small capacitor(150pf) against GND causes some programs to freak out in strange ways,causing Compumate to play strange(but still harmonic!) variations on its musics and "Pitfall II" this way made quite a wierd cacophony of its theme.(I recorded the results on cassette.) With another PIA chip the VCS just crashed when doing so.Strangeliely on my "32-In-1"-ROM the terrible bootleg PAL-convertion of Activison's "Skiing",that has wrong colours and always made pixel mess in the score counter,made no pixel mess when touching the TIA with the capacitor.(I though conclude timing problems after reading the "Stella Programmer's Guide".) Also the lenghth of the "Pole Position" speedometer bar varies a bit when just touching the PCB traces near the TIA with my hands.) Jay Tilton wrote: > > Glenn Saunders wrote: > > >The mortal Lippdinos wrote: > >: hmm... I'm not sure if the supercharger will work with the 7800, anyone? > > >It will work with the early 7800s with the expansion slot. I can vouch > >for that. > > Presence of the slot is not a reliable indicator. All the ones > manufactured very early (1984) have it, but some of the later ones > (1987) do too. > > 1984 models are well made, and will run any 2600 cart with no hitch. > > Later ones are not so well made. Supercharger, Decathlon, Robot Tank, > and Space Shuttle may or may not have problems on these, but it > depends on both the console and the cart. A cart that won't work on > one unit may work on another, and a unit that won't play one cart may > work with another copy of the same title. I didn't analyze my 7800's circuitry yet(I live in Germany,it's a PAL one and never made any problems with different carts.),but regarding that as well my "2600 Games-Library" as the 7800 have built-in game ROMs those are activated only when no cart is inserted,I conclude that it could be likely that 7800s use a similar diode-voltage-drop circuit to control the chip_select line of their "Asteroids" ROM.Though finding this diode and soldering a low-drop ger- manium type(eg. "AA112") parallel to it could in this case easily fix all the mentioned problems of american 7800 consoles. (Later someone wrote me that the problem with the VCS7800 US version apparent- ly has other reasons.) MAY THE SOFTWARE BE WITH YOU! *============================================================================* I CYBERYOGI Christian Oliver(=CO=) Windler I I (teachmaster of LOGOLOGIE - the first cyberage-religion!) I I ! I *=============================ABANDON=THE=BRUTALITY==========================*