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boggis the cat

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Everything posted by boggis the cat

  1. boggis the cat
    Possibly the resistance needs to be higher to allow for faster polling. There is always a transition time for signals. The game code runs in a ‘virtual’ 2600, and there is always a delay involved due to the hardware being controlled indirectly. There were a fair number of complaints about the lag with paddles on the older Flashbacks, and it appears that they have tried to resolve this. The trade-off seems to be incompatibility with original paddles.
  2. boggis the cat
    Just a note that you can remove one leg of a resistor or capacitor and leave it attached by the other. This makes putting it back in place easier if you have to do so. Transistors are best to remove entirely, or leave attached by one leg.
  3. boggis the cat
    Simon.Plata is the designer of this mod (see the first post). I slightly modified it to work well in my PAL machine. Check post #13 for a good circuit diagram and board layout. You would have to adapt the circuit to use the connection points you have now, or remove the mod entirely and start over with Simons mod. If you have a reasonably modern oscilloscope it should have a setting for TV signals. You set that then have to adjust the triggering to get an appropriate signal. To get a proper signal you are best to hook up to your TV as normal, then pick off the signal from the composite output it is likely easier to connect to the wiring on the board, just take care not to short anything. Your polarity (positive and negative) should be correct, but your values should be around 1 Vpp maximum volts, not millivolts (probably a probe setting issue, as you wouldnt get any picture at mV levels). 1.3 Vpp is way too high an output, so if that 1.3 mV is actually Vpp then that may be the issue but you really need to terminate the cable into the TV to get an accurate measurement (or connect a 75 ohm load across the output). Unfortunately, this is just something that you have to figure out for your particular modifications and the test gear you have. There is a lot of trial and error in this. An alternative would be to buy something like the UAV mod which is pre-built and much smarter than these basic signal level amplification hacks.
  4. boggis the cat
    There is a Bandai Namco variant listed, too. The pages look like they are ready to go live once they drop the pictures with links in. And the revised pricing.
  5. boggis the cat
    Good advice. Sometimes you don’t want to connect the ground on the probe. Phantom mains power is sometimes present on the ‘ground’ of TV connectors (no power there, but the signal will screw up the oscilloscope display). This confused me when I wasn’t getting an expected TV pattern, until I realised it was swamped out by mains coupled through the composite ground. Removed the ground and the signal was fine (TV and oscilloscope power from the same power strip). With a digital ‘scope you can capture some scanlines and check for problems. My thinking is that the signal amplitude may be a bit low, but it could be overdriven as well. The Atari doesn’t produce a fully compliant signal, so a ‘picky’ TV may not produce a good image — or any image, if you’re unlucky. I have a fairly new Sony LCD that does an OK job of displaying both NTSC and PAL 2600 output, so the claim sometimes made that no new TVs support the old systems isn’t correct.
  6. boggis the cat
    My guess is that the signal from the composite is out of spec. If you have an oscilloscope available then you can check this. The mod I used (from the top of this thread) uses two transistors to amplify the signal sufficiently. A single transistor mod may not have enough amplification. Transistors vary from part to part, so you may just have some that are lower in amplification.
  7. boggis the cat
    That construction technique is going to be prone to problems. I would start by looking at how close the component legs are to other solder joints —that transistor looks to be very close to the pads below, for example. That proximity may be producing an interaction that you don’t want. Ideally, you want to keep components well isolated and any wires as short as possible. That cable is unshielded and may be acting as an antenna, or a path for unwanted electrical interaction. It could be that the problem is unrelated to the additional components, too. Perhaps an existing connection was compromised in some way — a chip not making correct contact to all points in the socket, a socket having a bad solder joint, a damaged pad or track... Unfortunately, a lot of things can be wrong. If you can put up a photo of the output on the display that shows the problem that you are getting, or a short video clip if that gives a better example (e.g. colours shifting over time), then it may help figure out the cause.
  8. boggis the cat
    That depends on the emulation used and if the home brew requires certain things. It appears that the FB9 has a better emulation, as it has Pitfall II built in and there is some reference to ‘Stella’ (if I recall correctly) in the documentation. I just checked, and it refers to both Stella and a libretto library. (On the ‘user manual’ second sheet, near the bottom left corner.)
  9. boggis the cat
    If it is a general colour issue then you can use the colour adjustment for that. If it is something like shimmering colours then that may be a display issue: test on another display to verify that it isnt a compatibility issue. Recheck your modification points to be sure that you havent overlooked something. Possibly you may have accidentally shorted a couple of components. If you can post a photo it may help as someone may have had the same issue.
  10. boggis the cat
    The only suggestion I have is to check this on another display. It looks like a timing issue with the interlacing of the picture. Possibly you could find some information by doing a search on this subject, if it is consistent across two or more displays.
  11. boggis the cat
    Hi Bill. Does this mean that the original paddle controllers will not work on the Flashback 9?
  12. boggis the cat
    I noticed that the instructions say that controllers for the Flashback 8 are not compatible. It would be nice if these were standard Bluetooth controllers.
  13. boggis the cat
    I used 250 mW rated metal film. Probably anything would work fine, as no significant power is involved. You can add one in to blur the video if it appears too sharp, as Simon showed. I didnt use one, so it is optional. Use the parts and board layout that Simon posted in post number 13, here: http://atariage.com/forums/topic/271678-simple-diy-composite-video-mod/?p=3895187
  14. boggis the cat
    33K seemed to be about right. You may have to experiment a bit, or check the audio level on an oscilloscope — about 1 Vpeak seemed reasonable on the TV I used (although I think the standard may be 1 Vrms, or 1.4 Vpeak). Ideally, you want each signal amplitude — video and audio — to be as close as possible to specification.
  15. boggis the cat
    Thats good news. Always good to get a pay off from investing so much time in these creaky old machines. ? I replaced my TIA socket, too, as I was suspicious of it. However, it turned out to be the RIOT chip that had died. (Not a bad idea to replace sockets that look in bad condition, anyway.) Did you need to tweak the sound level at all? I found that the output was way too high, and ended up putting a fairly high resistance in series to drop it to a reasonable level.
  16. boggis the cat
    I have highlighted (yellow circles) some potential bad solder joints. Check continuity, and preferably redo these and any others that look dirty or appear to not contact the components and/or board well (dry joints). More suspect solder points, and a possible crack in a track (red arrow). Check continuity across that track, while putting (slight!) pressure on the reverse side. If it is faulty then route a wire to bypass it. After checking and fixing those solder points, try putting the transistor back and test if the system functions again. If so, then the ICs are OK. If you want to get a spare RIOT chip, they go by the part number UM6532, and are fairly widely available (eBay or Aliexpress or etc). Best of luck getting this working. It can be frustrating, but take your time and check your work as you go.
  17. boggis the cat
    If the system was working before you attempted the mod then it may not be the TIA. You may also want to check the RIOT chip, if the system just produces static or a bad picture (but a picture is being output: use a ‘scope set to detect the PAL TV trace). They can die, of course. I repaired the unit I modified, and it turned out to have a bad RIOT chip. (Bought five replacements, two were DOA.* Also bought two ‘working’ TIA chips, one of which was DOA. These are getting old and becoming cranky.) * Weird effects can be had from bad RIOT chips. I tested the five out, and one just wouldn’t work somclearly dead. One created some interesting effects on Pac-man: the joystick only worked down and left, and poor old paccy got embedded in the wall at the left of the playfield — bad RAM locations, I am guessing. (OTOH, the ghosts couldn’t reach him. Glass half full? )
  18. boggis the cat
    Check that these are the correct components. Different boards may have different configurations. You shouldnt get 5 V on two pins. High potential meaning > 2 V? If you can take some photos of your board then people may be able to help. Also, an oscilloscope is useful to trouble-shoot if you have access to one.
  19. boggis the cat
    If your PCB looks like that shown, then those instructions should be good. My 4-switch ‘Vader’ model is an odd-ball made in New Zealand back in the day, but the basic board layout was the same. If your PCB looks slightly different it may still use the same component designation, so look for the printed labels — often under components, for extra fun. Check by tracing the path back to another component — the audio will always come from the same source, and so with the video. A ground point and 5 V source can be taken from anywhere convenient, really. Just take care, and make sure you can reverse any change if necessary. I only lifted one end of components to be removed, then used a bit of heat-shrink to isolate them. This made the changes reversible. Getting the modulator out took a lot of effort, so you may want to consider leaving it in place and just cutting the five pins close to the board then taking them out. (It is a large piece of metal, so desoldering it was difficult. I would try to leave it in place if doing this again.) The circuit provided by “simon.plata” is pretty simple, but I built it on a breadboard first and connected it up to test prior to building on the small piece of PCB. My first attempt at the small PCB failed due to not laying the components out well. You can use the schematic for the PCB that Simon put here to guide you in building this on your own PCB.
  20. boggis the cat
    It isn’t unusual to only have the E6 values available. 75R is only in the E24 and E48 series, and not that common in my experience. 18R is in the E12 series, but often not included in bulk lots as I had on hand where they use the E6 series as the basis for selection of values. The tolerance doesn’t seem to have much to do with the series used, now. The metal film ones I have are supposedly 1%, and actually closer to 2% —although perhaps they got some black paint in their red. (Chinese sourced stuff is fine for general messing around, but probably not a good idea if you want precision.)
  21. boggis the cat
    Hi. Thanks for these. That board looks just slightly neater than my two efforts (The first of which decided it wouldnt work, so the one you see it my second improved attempt!) Shifting the breadboard circuit to protoboard was trickier that I had assumed, transistor pinouts being uncooperative. Just a note that R5 and R6 may be best to have a couple of pads available. I used a 33R and 43R in parallel to get ~18R for R5, and two 150R in parallel to get 75R for R6. This would require shifting the pads out and take a little more space, but would make it easier for people who dont have the exact resistors to hand.
  22. boggis the cat
    Hi. I have tried this modification on my PAL 2600A ('Vader'). It is a little different from the UK models, but almost the same. The components to remove are as here: https://www.thefuturewas8bit.com/index.php/2600_comp_mod I lifted one end of the resistors and capacitor, then put some heat-shrink over the free end. It should be easy enough to replace the transistor and adjustable inductor if required, but keeping track of these three components would be more problematic so I left them in place. Audio taken from the top of the board. Reinforced the wire with some heat shrink and routed it through the corner of the RF shield. I made an error and put a 1K pot in when I intended a 2K, so I set that to maximum. I found the sound level to be quite high (too hot a signal), so put a 33K resistor in series after testing. The audio line is going to a pin at the edge for convenience -- it was directly attached, then I added the 33K resistor in series to mute the sound slightly. The results are quite good, I think. Thanks for sharing your design.
  23. boggis the cat
    I don’t have a Harmony cartridge, unfortunately. It works with standard (PAL format) cartridges that I have tried. The switch that is normally TV Type is now a momentary action, so I am not sure that it would be fully compatible. (They could use a flip-flop to switch it each time the momentary action is made, but I don’t see one. The “MC14024BCP” is likely used to select the game from the built-in ROM: it is a shift register chip.)
  24. boggis the cat
    There is no real tactile feedback. You are mashing a flexing piece of metal against a screw, so not surprising. I actually thought they were clone joysticks until I looked closely. Very sneaky to mould the plastics to mimic the originals.
  25. boggis the cat
    Hi to all. I got hold of a 2600 'Vader' clone a while back, and it is a bit different from others I have seen. Produced in Hong Kong, no RF shielding, 64-in-1 built in games with re-purposed switches, and very odd joysticks. PCB has "8931" on it, which I am guessing is a date stamp for 1989, 31st week. [Edit: the chip stack marked "510002D" has an "8929" date stamp, so it is a 1989 clone.] Photos below. Console: Weird joystick (two supplied with console):
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