channelmaniac
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Posts posted by channelmaniac
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I'll have to work out how long a CR1225 will last powering a 62256 SRAM. It should be in years I would think.
It all depends on which version of the chip... There are standard power then there are low power standby versions. Find the lowest power standby version and you'll maximize your battery life.
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once I got a garbled title screen on Gorf but I can't get that to happen again
Sounds like bad DRAM. Do the modification on the board and replace those pesky 4116 DRAMs with some 4516 or 4164 types that are 5v only.
http://newlifegames.net/nlg/index.php?topic=40.msg11121#msg11121
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I see no RF input.
If it has no tuner, it is not a television, it is a monitor.
Is it possible to play game systems on this TV that use RCA cables?
Maybe...
CV, Intellivision, Atari 2600/5200/7800 - NO. Those RCA cables are carrying RF signals.
The item in the auction isn't a TV, but rather a monitor. TVs have tuners, this one doesn't that I can see. There's no RF input.
The only way you can play older game systems on it would be to modify them to have composite or s-video outputs.
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Bah...
Just fix the adapter.
Take a hammer and go all the way around the seam on the adapter's housing. Smack it on the short side of the seam repeatedly as you go around and around the seam. You'll crack the seam to where you can separate the 2 halves of the housing.
Once you have it apart, replace the electrolytic capacitors and resolder the whole thing.
Reassemble and wrap it in electrical tape to hold it together while you test. Once you verify it has been successfully repaired, epoxy the case back together.
RJ
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...cartridge-based, backward compatible (hardware and software) with 7800, 2600, Supercharger, AtariVox et al...built for arcade perfect ports and fresh new audio/graphic rich titles...built FOR developers and therefore built for gamers...
It needs a name - I propose The Cheetah
6502 based... with the RIOT chip which gave the 2600 its 128 bytes of RAM and I/O ports and TIA for compatibility... Should then run 100% of the 2600 games.
But then give it 32K of SRAM (a single 62256 SRAM chip will work nicely) and bitmapped graphics to go with that TIA.
Any unused lines on the cart slot can be repurposed for whatever you want.
Add in a nice, cheap sound chip and you are good to go. Some cheezy Yamaha FM sound generator will work nicely and not cost too much... plus there are plenty of code and music samples you can use for it.
RJ
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So yeah, the CPU on the 2600 is pretty much the same as the one in the NES. The NES CPU runs about 50% faster than the one on the 2600 though, but what makes the real difference is the video chip. The TIA needs constant CPU attention while rendering the screen in order to show anything meaningful, so there is very little free time left to process game logic. The NES has enough video memory for a whole frame, meaning that it can generate a full video frame without any CPU intervention. Video changes must be made during vertical blank, so the CPU is free for game logic while the screen is being rendered by the PPU (Picture Processing Unit).For those of you that collect computers, this is the same thing as comparing a Commodore VIC-20 to a Timex Sinclair 1000
The VIC-20 has a powerful video chip that does the graphics processing and rendering separate from the CPU.
The TS-1000 is set up without such a chip and the screen rendering is done by the CPU.
Run a BASIC program on both and the VIC will run circles around the TS-1000 even though the TS-1000's clock speed is over 3x that of the VIC-20.
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I turned it on without a cartridge in and the font is corrupted.
That sounds like a bad video RAM chip. Knowing what it looks like can narrow down which chip is the problem.
If you have a logic probe then look for a data out line on the 4116 DRAM chip that is stuck low.
If you don't have a logic probe then measure resistance on the data out line to see if you find one that has much lower resistance than the others.
Data sheets on the DRAM can be found at http://www.datasheetarchive.com
You can also mod the unit to take 4516 or 4164 DRAMs which are 5v only DRAM chips. This gets you away from the power switch issues and they run cooler too. See my repair log entry here: http://newlifegames.net/nlg/index.php?topic=40.msg11121#msg11121 for a write up on doing that.
If it's something you don't want or can't do then there are members here like me that can do that for you as a service.
RJ
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Prime example on why i dont use CL
There has been a rash of idiocy on the Dallas CL lately... Someone keeps posting free items, mostly treadmills, and saying "it's light enough you can pick up by yourself"... and that "I'm leaving soon because of a job"... Sounds real fishy to see it posted over and over with different treadmill brands on the same day.
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yep saw sparks and I have everything set up correctly. I have some other Ataris and they all work on my TV except for this one.
Take a voltmeter and check the output of the 5v regulator to make sure it's putting out between 4.8 and 5.2 volts DC. If not, replace it.
If it is then you have a bad chip. If you have no output at all - no junk lines or anything then replace the TIA... otherwise it's a crapshoot as any of the 3 main ICs can cause those symptoms.
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I ran into the same problem with one of those power supplies.
http://newlifegames.net/nlg/index.php?topic=40.msg94#msg94
It had 4 obviously bad solder joints - to the point where the pin was through the hole with no solder sticking to it.
You can crack them open by rapping them with a hammer. I outlined the procedure in my repair logs. Once you get it open just resolder the whole board inside it.
RJ
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According to the schematic, you still need the -5v for the silly controller port logic.
I looked through the Mouser.com website and couldn't find a single output DC-DC converter that had an output of -5v. It looks like you'll need to get a dual output unit and put a simple resistor across the positive output to load it properly. Then you can use the negative output to power the port logic.
RJ
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NiCd and NiMH are simple... you need a battery, a DC blocking diode (to stop battery flow when +5 is on), and a 470 ohm resistor to charge it from +5v.
Li-Ion - EEEEEEEK. DO NOT charge without a charge regulator IC. Those things go up in toxic smoke and lots of flame if not charged properly.
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I'd go RIOT first then 6507... and TIA for last.
RIOT = RAM, I/O, and Timer. Without RAM you get squat. Without CPU you get squat. But in either case you'll get lines and random stuff on the screen.
RIOT is usually the first to go since it controls the sticks and other things.
RJ
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Try this from my repair logs site:
http://newlifegames.net/nlg/index.php?topi...g11121#msg11121
I wrote down what I did when I modified a CV for +5v only DRAM.
RJ
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PM Responded to.
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I picked up a bunch of loose carts, but rather than bore everyone with all the commons, here are the two carts listed as a "4" on the rarity guide.
M.A.D. by USGames (Standard, not beveled)
61 Basic Math
Both are in what I would consider very good shape for their age.
M.A.D. has a bit of sticker residue on it, 1 label scratch (small) and 1 label nick.
61 Basic Math has 2 nicks in the label, the end label is nice.
Can take pics if you really require them.
$5ea plus shipping.
Or will trade for interesting IC chips or old dead computer/console boards. (8-bit NES or older, 386 PC or older)
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You may also consider checking the connections on A12 and A13. Those pins actually are not needed, so you could even try bending those up and pulling them high.Actually, if they aren't used you should tie them LOW (ground) if you programmed the device starting at $0000 on the EPROM. Otherwise you are selecting a higher memory area that may not have any data in it when you tie unused address lines high.
RJ
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EEEK!
Better double check. Some of you are saying 9v AC adapter. The 2600 uses 9v DC.
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I have an old Fluke I'd sell ya for $25 shipped. I'll have to dig it out.
I don't recall if I have test leads for it, but if I do they are probably old and need replacing.
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WTF????
Why would you ever solder on a coin cell battery? There's no safe way to do that! AA/C/D and other big rechargeable cells, yes. Button cells? NEVER! Coin cells? NEVER!
Take the old one to Batteries Plus and buy a replacement coin cell. They will spot weld tabs on batteries they sell for FREE.
It's MUCH safer!
By the way, that stuff inside those lithium coin cells is highly toxic and will eat traces like candy. Make sure to clean up any gunk from it VERY well.
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Hmmm... if that's all it is then I wonder if the same mod circuits for the CV would work. It's a simple amplifier/buffer.
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Colecovision Video Mod
in Hardware
Posted · Edited by channelmaniac
Sorry, was out hunting for the past couple of days.
Can you post clear, high-res pics of the completed kit board and where you soldered everything to the CV board and RF modulator?
Also, page 6 of the instructions tells (and shows with a picture) where the wires get soldered to the RF modulator and the picture on page 3 shows where the grounds are for the coax braid on the mod board itself.
Please ensure that
A) The 2 electrolytic caps are installed properly - they are polarized.
B) The ground shields and center wires on the coax are not reversed on one end. That would ground out the signals.
C) The IC chip is installed correctly. It can be plugged in backwards which would kill it.
The small 47pf capacitor is not polarized and can be installed in either direction.
Thanks!
RJ