Paul Slocum Posted June 9, 2004 Share Posted June 9, 2004 My instructions do say to feed the tinned ends through the cabinet back' date=' but it's easy to miss. Again... photos or illustrations would be most helpful.[/quote'] Ha, you're right. I missed it even the second time I read through to double check before I posted. I THINK THE UPPERCASE PART TELLING ME TO FEED IT THROUGH THE RF SHIELD DISTRACTED ME. Haha. -paul Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 9, 2004 Share Posted June 9, 2004 +-------+-------+-----------+----------------+ | pin 6 | pin 9 | sat pot | chroma voltage | (measured) +-------+-------+-----------+----------------+ | 0v | 0v | no effect | 1.37v | (1.368v) | 0v | +5v | no effect | 1.93v | (1.934v) | +5v | 0v | left | 1.58v | (1.579v) | +5v | 0v | right | 0.833v | (0.866v) | +5v | +5v | left | 1.72v | (1.723v) | +5v | +5v | right | 2.47v | (2.431v) +-------+-------+-----------+----------------+ Hmmm....that looks like crap. I don't know how to get a monospaced font in here' date=' so you'll have to deal. Anyway, whatt you measure should be very close to the design spec above. When I say very close you should hear "almost exactly...within a few mV". When the pot is turned to the right and pin 6 = +5v, the values could be a few tens of mV away, but no more. This is because pots don't truly zero out sometimes. Some of your numbers are way off. So try repeating the measurements, but this time measure the voltage at the middle pin of the saturation pot. It's the one right beside the big electrolytic cap. For your peace of mind, these are indeed the values you should see. I included the measured values from my partially stuffed test board next to the calculate values. -Chris[/quote'] I don't understand the chart. Am I suppose to connect the pin 6 and pin 9 to something? Umm, sorry. It's a truth table. Pins 6 and 9 and the pot position are the inputs and the chroma voltage (at the middle pin of the pot) is the output. For each row, you connect the inputs as directed (e.g. for the second line: pin 6 = 0v, pin 9 = +5v, pot = "don't care"). Then you measure the output. The "chroma voltage" column is what you should expect, and beside that I added the value that I actually measured from my unit. -Chris Sorry for me being a total dufus, but I don't understand the table. Let's see if I'm doing this right. Example: pin 6 = 0v, pin 9 = +5v, pot = "no effect". Does that mean I do this: 1. Connect wire from pin 6 to pin 1 (0V) 2. Connect another wire from pin 9 to pin 20 (+5V) 3. Sat pot position is irrelevant 4. Place black probe on pin 1 5. Place red probe on middle pin on sat pot 6. Read multimeter reading Am I correct? Thanks for all your help so far. Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 9, 2004 Share Posted June 9, 2004 I noticed my black is a little too light. HMOVE bars are clearly visible even on a black background. Will adjusting one of the pots fix this? It depends. Or rather...yes you should be able to do that. There are 3 pots: contrast, brightness, and color sat. If you have a rev 0 board, I think they're labeled. If you have a rev 1 board, they are NOT labeled as there wasn't really any space available. On that board, the sat control is all by itself. The contrast is next to a resistor pack, and the brightness control is right next to that, towards the board's center. Turn the brightness all the way to the left (I think it's left). You probably shouldn't mess with the contrast pot...that'll change the sync level...too far away from spec and you can guess what happens. If this doesn't work, let me know and we can try adjusting the contrast. -Chris Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 9, 2004 Share Posted June 9, 2004 Let's see if I'm doing this right. Example: pin 6 = 0v' date=' pin 9 = +5v, pot = "no effect". Does that mean I do this: 1. Connect wire from pin 6 to pin 1 (0V) 2. Connect another wire from pin 9 to pin 20 (+5V) 3. Sat pot position is irrelevant 4. Place black probe on pin 1 5. Place red probe on middle pin on sat pot 6. Read multimeter reading Am I correct? Thanks for all your help so far. [/quote'] That's exactly right! In the example you've given, the reading should be 1.93V as given in the "chroma voltage" column for that row. Good luck! -Chris Quote Link to comment Share on other sites More sharing options...
+SpiceWare Posted June 9, 2004 Share Posted June 9, 2004 Even though Chris had warned me in advance' date=' I stupidly forgot to feed the first pair of cables through the hole before soldering them in. Rather than desolder the cables' date=' I simply got out my dremel tool and made the hole a bit larger.[/quote''] I did the exact same thing. Fortunately, I didn't have to do much cutting - only about 1/16 of an inch. Shame on Atari for not making the hole bigger in the first place. I'll be adding this to my overview of the mod, too. Me too. Now I don't feel so bad Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 10, 2004 Share Posted June 10, 2004 +-------+-------+-----------+----------------+ | pin 6 | pin 9 | sat pot | chroma voltage | (measured) +-------+-------+-----------+----------------+ | 0v | 0v | no effect | 1.37v | (1.368v) | 0v | +5v | no effect | 1.93v | (1.934v) | +5v | 0v | left | 1.58v | (1.579v) | +5v | 0v | right | 0.833v | (0.866v) | +5v | +5v | left | 1.72v | (1.723v) | +5v | +5v | right | 2.47v | (2.431v) +-------+-------+-----------+----------------+ Hmmm....that looks like crap. I don't know how to get a monospaced font in here' date=' so you'll have to deal. Anyway, whatt you measure should be very close to the design spec above. When I say very close you should hear "almost exactly...within a few mV". When the pot is turned to the right and pin 6 = +5v, the values could be a few tens of mV away, but no more. This is because pots don't truly zero out sometimes. Some of your numbers are way off. So try repeating the measurements, but this time measure the voltage at the middle pin of the saturation pot. It's the one right beside the big electrolytic cap. For your peace of mind, these are indeed the values you should see. I included the measured values from my partially stuffed test board next to the calculate values. -Chris[/quote'] I'm still getting numbers way off. Rows 1&2, I get 2.02V Rows 3&5, I get 1.74V Rows 4&6, I get 2.45V Hmmm.... Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 10, 2004 Share Posted June 10, 2004 I'm still getting numbers way off. Rows 1&2' date=' I get 2.02V Rows 3&5, I get 1.74V Rows 4&6, I get 2.45V Hmmm....[/quote'] Ok. Let's trace the signal from pin 9 through to the pot. There is a chip called "U4" near the pot (the label is under the chip). U4 is adjacent to C4 and the TIA. See the picture below. Since we're dealing with more than one chip, I'll start calling the TIA pins by their names: pin 1 is "ground", pin 20 is "vcc", pin 6 is "blank" and pin 9 is "color". All other pins in this post will refer to the chip U4. | | U4 | | _ _ | | -| / |- | | -| |- | | -| |- | TIA socket | -| |- | | pin 5 --| |- | | pin 6 --| |-- pin 9 | | -|____|-- pin 8 | | ______ | | | | | | C4 |______| | | | | | | First, a sanity check. Connect color to ground and measure the voltage at pins 5 and 9. When color is grounded, pins 5 and 9 should both be 0v. When color is left unconnected, pins 5 and 9 should both be +5v or +3.3v, depending on which version of the chip is installed on your board. If this checks out, then proceed with the next check. Turn the pot all the way to the right. Connect blank to ground and measure pins 6 and 8. When color is grounded, pin 8 should be 0v and pin 6 should be 1.37v. When color is floating, pin8 should be 3.3v and pin 6 should be 1.93v. Now leave blank floating and measure pins 6 and 8 again. When color is grounded, pin 6 should be 0v and pin 8 should be 0.833v. When color is floating, pin 6 should be 3.3v and pin 8 should be 2.47v. I think this will help us find the problem. -Chris Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 10, 2004 Share Posted June 10, 2004 Oh, BTW..."floating" means "not connected". -Chris Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 11, 2004 Share Posted June 11, 2004 Ok. Let's trace the signal from pin 9 through to the pot. There is a chip called "U4" near the pot (the label is under the chip). U4 is adjacent to C4 and the TIA. See the picture below. Since we're dealing with more than one chip' date=' I'll start calling the TIA pins by their names: pin 1 is "ground", pin 20 is "vcc", pin 6 is "blank" and pin 9 is "color". All other pins in this post will refer to the chip U4. | | U4 | | _ _ | | -| / |- | | -| |- | | -| |- | TIA socket | -| |- | | pin 5 --| |- | | pin 6 --| |-- pin 9 | | -|____|-- pin 8 | | ______ | | | | | | C4 |______| | | | | | | First, a sanity check. Connect color to ground and measure the voltage at pins 5 and 9. When color is grounded, pins 5 and 9 should both be 0v. [/quote'] I got +5v. When color is left unconnected, pins 5 and 9 should both be +5v or +3.3v, depending on which version of the chip is installed on your board. If this checks out, then proceed with the next check. I got +5v again. That looks good I guess. Turn the pot all the way to the right. Connect blank to ground and measure pins 6 and 8. When color is grounded, pin 8 should be 0v and pin 6 should be 1.37v. I got 2.45v and 3.26v respectively. When color is floating, pin8 should be 3.3v and pin 6 should be 1.93v. Hmm. I got 2.45v and 3.26v respectively again. Now leave blank floating and measure pins 6 and 8 again. When color is grounded, pin 6 should be 0v and pin 8 should be 0.833v. I got 3.26v and 2.48v respectively. When color is floating, pin 6 should be 3.3v and pin 8 should be 2.47v. I got 3.26v and 2.48v respectively. Wow, I got a match! Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 11, 2004 Share Posted June 11, 2004 First' date=' a sanity check. Connect color to ground and measure the voltage at pins 5 and 9. When color is grounded, pins 5 and 9 should both be 0v. [/quote'] I got +5v. Aaaaaah! Not good! Ok, I think we've found something. So let me re-describe this in detail. Connect TIA pin 1 to TIA pin 9. Measure U4 pin 5. If the voltage here is not 0v, then that's the problem....your color signal from the TIA isn't even making it onto the board! Please verify the measurement and let me know. I'll be on vacation for the next few days. I'll try to check in at least once a day, beginning Monday. -Chris Quote Link to comment Share on other sites More sharing options...
+Nathan Strum Posted June 15, 2004 Share Posted June 15, 2004 So I finally get around to bringing my 2600 into work. Do the frame capture thing, update the website, all that. It looks great on a broadcast NTSC monitor! Really first-rate. But now the sound has stopped working. I've tried it in two 2600s, too. I think I'll go back to RF. Any ideas? I've got continuity from the mod board through the audio cables. Pins 11 and 12 (whichever the two audio ones are) have continuity from the TIA chip through the wirewrap all the way to the main board. What else can I check? Quote Link to comment Share on other sites More sharing options...
+Nathan Strum Posted June 16, 2004 Share Posted June 16, 2004 Too bad we can't edit posts... Anyway, audio is fixed. It wasn't the mod - it was an audio interface (unbalanced RCA to balanced XLR) that I was running it through for capturing. Apparently the audio coming off the mod is too hot for it to handle. Once I bypassed that, the audio was fine. My 2600 seems happy now, although once the audio was going again, it asked me to please stop taking it apart. (I'm still trying to figure out exactly how it did that, too. All it's said up until now had been "Quadrun Quadrun Quadrun". ) Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 18, 2004 Share Posted June 18, 2004 First, a sanity check. Connect color to ground and measure the voltage at pins 5 and 9. When color is grounded, pins 5 and 9 should both be 0v. I got +5v. Aaaaaah! Not good! Ok, I think we've found something. So let me re-describe this in detail. Connect TIA pin 1 to TIA pin 9. Measure U4 pin 5. If the voltage here is not 0v, then that's the problem....your color signal from the TIA isn't even making it onto the board! Please verify the measurement and let me know. I'll be on vacation for the next few days. I'll try to check in at least once a day, beginning Monday. -Chris Ok, I double checked and still got +5V at pin 5 on U4 when TIA pins 1 and 9 are connected. So what does it mean that the color signal isn't making it to the board? Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 18, 2004 Share Posted June 18, 2004 Anyway, audio is fixed. It wasn't the mod - it was an audio interface (unbalanced RCA to balanced XLR) that I was running it through for capturing. Apparently the audio coming off the mod is too hot for it to handle. Once I bypassed that, the audio was fine. Glad you got it working! Out of curiosity, what are the specs for balanced XLR? I could probably make a component change to accomodate it. -Chris Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 18, 2004 Share Posted June 18, 2004 Ok, I double checked and still got +5V at pin 5 on U4 when TIA pins 1 and 9 are connected. So what does it mean that the color signal isn't making it to the board? Well, TIA pin 9 (color) is the same piece of metal (in theory) as U4 pins 5 and 9. So the voltages should always be identical, no matter what. If your meter has a continuity mode, check to see if there is continuity from TIA pin 9 to U4 pin 9 and pin 5. There may be a broken solder joint. -Chris Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 21, 2004 Share Posted June 21, 2004 Ok, I double checked and still got +5V at pin 5 on U4 when TIA pins 1 and 9 are connected. So what does it mean that the color signal isn't making it to the board? Well, TIA pin 9 (color) is the same piece of metal (in theory) as U4 pins 5 and 9. So the voltages should always be identical, no matter what. If your meter has a continuity mode, check to see if there is continuity from TIA pin 9 to U4 pin 9 and pin 5. There may be a broken solder joint. -Chris What does "continuity" mode look like? The only tests my multimeter can do are DC voltage, DC current, AC voltage, resistance, diode and transistor tests. Can I use one of the other tests as a continuity test? Quote Link to comment Share on other sites More sharing options...
+Mitch Posted June 21, 2004 Share Posted June 21, 2004 Resistance probably is the one you are looking for. Set it to that and touch your two leads together, it should give you 0 resistance. Then connect them to the two test points, if it registers much above 0 then there is a problem. Mitch Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 21, 2004 Share Posted June 21, 2004 Thanks Mitch! I'm still traveling...will finally be home late this week. I probably won't be able to check in again until Saturday. -Chris Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 21, 2004 Share Posted June 21, 2004 I noticed my black is a little too light. HMOVE bars are clearly visible even on a black background. Will adjusting one of the pots fix this? Did you get this fixed Paul? -Chris Quote Link to comment Share on other sites More sharing options...
+Nathan Strum Posted June 21, 2004 Share Posted June 21, 2004 Out of curiosity, what are the specs for balanced XLR? I could probably make a component change to accomodate it. This is the audio interface that didn't like the mod's levels. I was able to work around it easily enough, and I doubt it'll ever be an issue. I had the 2600 hooked up to a routing switcher that requires balanced audio, and I suspect few people will ever need it (except maybe Paul Slocum ). Which reminds me... The Atari 2600 Video Mods Comparison Project has been completely updated. I've redone all of the tests, recaptured all new (and better) images, updated all of the results, expanded the information, and added the CyberTech mod to it. Whew! That was a lot of work. Enjoy! Quote Link to comment Share on other sites More sharing options...
aradia Posted June 23, 2004 Share Posted June 23, 2004 Anyway, audio is fixed. It wasn't the mod - it was an audio interface (unbalanced RCA to balanced XLR) that I was running it through for capturing. Apparently the audio coming off the mod is too hot for it to handle. Once I bypassed that, the audio was fine. Glad you got it working! Out of curiosity, what are the specs for balanced XLR? I could probably make a component change to accomodate it. -Chris Not really worth the time it would take to attempt. Nathan was correct in saying it wasn't the mod; it was the way the connection was made between the mod and his audio interface. He probably just didn't make the proper connection (with the proper adapters, et cetera). XLR has no specs, because it's just a connector. Just like RCA or 1/4" TRS/TS (phono). It's a large three-prong connector designed to make a sturdy, positive connection, and is generally only used for pro/prosumer audio equipment. Like TRS plugs, but unlike RCA and TS plugs, it can be balanced (signal+inverted signal+ground) or unbalanced (signal+ground) while remaining shielded. RCA and TS plugs can only be unbalanced+shielded or balanced+unshielded because there are only two signal paths. XLR connectors are generally used for single channels, but like TRS plugs, can technically be used to make unbalanced stereo channel connections as well. The problem comes in the input and output specs. I don't know what the output spec for your audio mod is, or what the input for Nathan's audio interface is, but pro audio equipment is usually +4db while most consumer equipment is -10db. Instrument-level inputs are usually Hi-Z (~10k), line-level inputs are usually Lo-Z (~300-600), outputs are usually Lo-Z (~300-600). There is no strict standard for which pins carry which signals, so proper adapter selection is important to be sure that the correct XLR pins connect to the correct [RCA, TRS, TS] pins. Impedence matching transformers may also need to be used. Going from unabalanced to balanced, though, is a serious pain in the butt. RFI and ground loops are potentially irritating problems, and the best solution is to use a DI box. Nathan's problem could've been any number of things. If his audio interface only accepts balanced XLR, and he didn't use a DI box to make the connection, that would be my best guess. The only way for you to support this onboard would be to offer, say, a balanced 600 ohm line level 1/4" TRS jack. But to be honest, as I said in the beginning of this post, it really isn't worth your time. Not many people even own equipment that takes balanced inputs, and most of us who do so usually have an enormous pile of adapters, matching transformers, and other myriad items to go from every possible input to every possible output. After I stopped doing audio engineering, the only stuff I didn't sell was, surprise, an entire mixer bag full of adapters. If I finally break down and give up on the CD4050 mod, and buy your mod instead, I'll try hooking it up to a balanced studio monitor I have and let you know what the problem was. =) Whew. Sorry for any obnoxious audiobabble, but that's my major electronics background. Oh yeah... Hi! Long-time Atari fan, new lurker on atariage. It's nice to meet y'all. =) Quote Link to comment Share on other sites More sharing options...
aradia Posted June 23, 2004 Share Posted June 23, 2004 Hrm. I just noticed that Nathan posted a link to the DI box he used. Odd that it didn't work properly. Even with extremely low-level output from your mod, it looks like it should've had plenty of gain, and since he's used it before, it should obviously supply the right pinouts for the XLR. I'm kinda curious now about what the level and impedence is for the audio output on the mod.... Oh well. Quote Link to comment Share on other sites More sharing options...
atarian1 Posted June 26, 2004 Share Posted June 26, 2004 Ok, I double checked and still got +5V at pin 5 on U4 when TIA pins 1 and 9 are connected. So what does it mean that the color signal isn't making it to the board? Well, TIA pin 9 (color) is the same piece of metal (in theory) as U4 pins 5 and 9. So the voltages should always be identical, no matter what. If your meter has a continuity mode, check to see if there is continuity from TIA pin 9 to U4 pin 9 and pin 5. There may be a broken solder joint. -Chris Ok, I switch my multimeter to 2000K resistance setting and checked to make sure it zeroed out when the two leads touched. I placed the black probe on TIA pin 9 and red probe on U4 pin 9 and got '009'. I moved the red probe to U4 pin 5 and got '009' again. Doesn't look good, eh? Quote Link to comment Share on other sites More sharing options...
cwilkson Posted June 28, 2004 Share Posted June 28, 2004 Ok, I switch my multimeter to 2000K resistance setting and checked to make sure it zeroed out when the two leads touched. I placed the black probe on TIA pin 9 and red probe on U4 pin 9 and got '009'. I moved the red probe to U4 pin 5 and got '009' again. Doesn't look good, eh? Hmmm. It looks *weird*. 9 Ohms is high, but probably acceptable. But that doesn't make sense with the other data we've gathered. Did you already tell me which board rev you have? I've been operating with the belief that you have a rev 1.0 board. It seems like I read that somewhere, but now I can't find it. Let's switch this offline, so that I won't lose anything else you tell me. PM me with which board you have. The rectangle (rev 0), or the L-shaped one (rev 1). -Chris Quote Link to comment Share on other sites More sharing options...
cwilkson Posted July 12, 2004 Share Posted July 12, 2004 An update for those were were following atarian1's CyberTech issues. [copied from an email sent to atarian1] There was nothing wrong with your video card. The problem turned out to be your solder connections. All 16 of them were cold solder joints. When the unit arrived all but one had broken loose. I assume most of that was due to being jostled during shipping, but they would have failed eventually. The exact problem was one (or more) of the broken connections had shorted. It was killing the chroma and affecting the power supply intermitently. I repaired the connections and everything worked just fine. One other thing. Your motherboard TIA socket looked like it had been abused more than was good for it, so I replaced it for you. Just in case. Chris CyberTech Quote Link to comment Share on other sites More sharing options...
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