Andromeda Stardust Posted November 30, 2016 Share Posted November 30, 2016 Ah - but see there's my same problem. I believe my POKEY might be damaged, because I used a heat gun to de-solder it from it's Ballblazer board. I don't have a de-soldering iron to do the job properly - so I was hoping someone had a spare loose one where there wouldn't be risk of damage from trying to remove it from a BB board. Thanks for the offer though, I do appreciate it! I tried fiddling with my desolder iron but I think the tip is toast and I need to replace it. The solder on those 30-year-old PCBs are really stubborn. I ultimately used an oven set to 400 degrees until the chip fell out. Pokey worked fine afterwords. However using a heat gun like you did creates uneven hot spots. Solder melts around 200 degrees C. Silicon starts to break down at 300, so if you used a heat gun, or anything with a flame, it is possible you overcooked portions of the chip before the solder fully melted elsewhere. I think melting points is 375 F for 60/40 solder and 400-425 for RoHS compliant lead free solder, depending on formulation. Get an aluminum pie pan and put it in an oven. Make stilts out of a paper clips to raise the PCB off the surface. Set the oven to 400F on bake. This will create slow, even, controlled heating without risking uneven thermal expansion or raise the die to breakdown temperature. As soon as the chips drop, turn off the oven and remove the pie pan. Collect the chips and PCB, then discard the pie pan. You won't want to eat off it since it has been exposed to "chemicals known in the state of California to cause cancer, birth defects, or other reproductive harm." The oven should be safe to use for food since the pie pan will collect any solder residue or refuse. People use Toaster ovens for reflow work all the time to manually install SMT chips, which besides the package size aren't much different than DIP chips, so it shouldn't damage anything so long as you use the lowest temperature setting possible to melt the solder and drop the chips. Link to comment Share on other sites More sharing options...
Everett1954 Posted November 30, 2016 Share Posted November 30, 2016 Never tried the oven method but it sounds like it works. How long did you have to leave the BallBlazer Board in the oven before the Pokey chip fell out? I am lucky, i have a $1000 Metcal brand Desoldering/soldering station at work that I can use. It can desolder multi-layer boards with thick ground planes. Best Iron I have ever used (I've tried the Hakko' Weller etc.) At home i use a 45W iron with a flat tip and a Solder Pullit manual desoldering pump (both cheap) and some good old solder wick. I am going to try this oven method on a scrap board. Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted November 30, 2016 Share Posted November 30, 2016 I could never get solder wick to work for me so I have a Hakko FR300 de-soldering iron. It has a temperature dial on the bottom of it designed for multi-layer boards. For these old consoles I tend to use the setting between single and 2 layer boards which is about 325 degrees. However, when working with much older systems like the original heavy sixers and especially the damn Colecovision, I have to use slightly higher temps to get the solder to finally give way to my iron. Anyway, since I've gotten the FR300, I haven't had any issues with pulled traces and the like as I did with my standard iron and manual solder sucker. 1 Link to comment Share on other sites More sharing options...
Greg2600 Posted December 1, 2016 Share Posted December 1, 2016 FWIW my 7800 does not seem to like Robot Tank or Freeway, though River Raid worked fine! Were Activision 2600 carts a mixed bag? 1 Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 1, 2016 Share Posted December 1, 2016 Never tried the oven method but it sounds like it works. How long did you have to leave the BallBlazer Board in the oven before the Pokey chip fell out? It was a minute or so after the oven thermostat clicked off when they fell. I did not time the thing. The Ballblazer mask ROM dropped first, quickly followed seconds later by the Pokey chip. I promptly turned off the oven and removed the pan after they dropped. There were also a couple resistors and other junk that fell out as well. It's easier if you don't preheat the oven so you can prop up the PCB up in the pan, otherwise it might fall over when you move it. Chips drop out surprisingly clean as the surface tension of the solder keeps most of it secured to the vias. At 400 F I did not notice any browning or delamination on the green Ballblazer PCB, and the printed text on the chip is still white and did not turn. If you use a hot air gun to desolder the chips and notice browning or delamination of the PCB, you are cooking it way too hot and may damage the silicon. Link to comment Share on other sites More sharing options...
RevEng Posted December 6, 2016 Share Posted December 6, 2016 For those that can partially run games on your Concerto, would you mind running the attached 7800 utility cart? From some of the failures it might be instructive to run the "internal RAM test" and see what it returns. I've disabled the pokey in the header, to avoid any problems with it. 7800utilitycart.bas.a78 3 Link to comment Share on other sites More sharing options...
Jinks Posted December 6, 2016 Share Posted December 6, 2016 I loaded the utility cart from the rom I already had and found this info. Ram page 0 page 1 area 18 area 21 area 22 all passed. Console info NTSC console 16kb bios CRC EDB9 4kb bios CRC D337 NTSC1 4k Bios found 4k Pokey found. I do not have a pokey installed btw.. I will try yours at some point hopefully soon. This file I had seemed to give a white screen first 6 powerups then slightly garbled graphics as in text 1/2 off the screen then worked perfect 3 out of 5 powerups. Link to comment Share on other sites More sharing options...
RevEng Posted December 6, 2016 Share Posted December 6, 2016 Thanks... this version has mirror checks as part of the "internal RAM test". It would be good to confirm the mirrors passed. Some homebrews use them, but I don't think the original commercial roms did, so it would at least somewhat fit the pattern of failure some are seeing. The utility probes for POKEY chips. I wonder if Concerto is automatically mapping a POKEY if it detects the probe. I know you don't actually have one - something else must be fooling the detection. 1 Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 6, 2016 Share Posted December 6, 2016 For those that can partially run games on your Concerto, would you mind running the attached 7800 utility cart? From some of the failures it might be instructive to run the "internal RAM test" and see what it returns. I've disabled the pokey in the header, to avoid any problems with it. I'll try it later. My 7800 testcart ROM totally fails with black screen though. Link to comment Share on other sites More sharing options...
Jinks Posted December 6, 2016 Share Posted December 6, 2016 Thanks... this version has mirror checks as part of the "internal RAM test". It would be good to confirm the mirrors passed. Some homebrews use them, but I don't think the original commercial roms did, so it would at least somewhat fit the pattern of failure some are seeing. The utility probes for POKEY chips. I wonder if Concerto is automatically mapping a POKEY if it detects the probe. I know you don't actually have one - something else must be fooling the detection. Yeah when the program works the sound test will crash the program when it does the pokey audio channel 0 it freezes. Link to comment Share on other sites More sharing options...
Everett1954 Posted December 6, 2016 Share Posted December 6, 2016 I will try the 7800 utility cart file this evening on the low current draw Concerto. So far it acts the same as my previous one, Menu not being populated most of the times, Lots of freezing and video garbage and sometimes the games load to a blank or all white screen. Link to comment Share on other sites More sharing options...
Trebor Posted December 6, 2016 Share Posted December 6, 2016 I'll try it later. My 7800 testcart ROM totally fails with black screen though. The "testcart ROM" is that the Diagnostic Cart ROM image that should produce what is shown in this video? If so, the black screen is normal for the first ~10-15 seconds. It is running the diagnostic. Once completed, you should see what is shown in the video link. Anything besides the above, here's a summary of what it means. 1 Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 7, 2016 Share Posted December 7, 2016 The "testcart ROM" is that the Diagnostic Cart ROM image that should produce what is shown in this video? If so, the black screen is normal for the first ~10-15 seconds. It is running the diagnostic. Once completed, you should see what is shown in the video link. Anything besides the above, here's a summary of what it means. LOL. I just assumed it didn't work and powered off. 2 Link to comment Share on other sites More sharing options...
+groundtrooper Posted December 7, 2016 Share Posted December 7, 2016 LOL. I just assumed it didn't work and powered off. Not related to Concerto but I did the same thing with my Mateo flash cart and the Test Cart Rom. Then I figured out that it took a bit to do the tests. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
rayik Posted December 7, 2016 Share Posted December 7, 2016 The solder on those 30-year-old PCBs are really stubborn. expansion or raise the die to breakdown temperature. It may seem counter intuitive, but the trick is to add new solder to each solder points. They will then desoldering quite easily 1 Link to comment Share on other sites More sharing options...
Jinks Posted December 7, 2016 Share Posted December 7, 2016 It may seem counter intuitive, but the trick is to add new solder to each solder points. They will then desoldering quite easilyflux helps... but maybe its just me.. Link to comment Share on other sites More sharing options...
rayik Posted December 7, 2016 Share Posted December 7, 2016 flux helps... but maybe its just me.. New solder really works. Just try it sometime Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 7, 2016 Share Posted December 7, 2016 For those that can partially run games on your Concerto, would you mind running the attached 7800 utility cart? From some of the failures it might be instructive to run the "internal RAM test" and see what it returns. I've disabled the pokey in the header, to avoid any problems with it. I tested your new ROM. Crashes immediately upon boot with garbage onscreen. EDIT: Okay after subsequent playthroughs, the ROM works. Hangs after PASSED screen on the RAM test though. Many ROMs are still corrupted though. Does the test ROM check it's own integrity? A ROM that tests it's own checksum might be useful. Link to comment Share on other sites More sharing options...
RevEng Posted December 7, 2016 Share Posted December 7, 2016 EDIT: Okay after subsequent playthroughs, the ROM works. Hangs after PASSED screen on the RAM test though. Many ROMs are still corrupted though. Does the test ROM check it's own integrity? A ROM that tests it's own checksum might be useful. Ok, so in the RAM test everything passed including the mirrors? The integrity check would definitely be useful in this case. I'll need to come up with an external utility to insert a checksum, since it isn't known until the rom is fully assembled. 2 Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 8, 2016 Share Posted December 8, 2016 I played Ms Pacman 320 Pokey again. One of the rare times it got past the title screen after I booted. First maze was not garbled and I could not pass through walls either (previously the few times this game loaded, I was able to pass through walls). Off to a very good start. Then I ate some ghosts and quickly realized the eyes did not return to the ghost chamber but scrolled right continuously without entering the door, so there was still some ROM corruption. However this allowed me to cheat and play further into the game than normal without losing life, since a ghost eaten is eliminated until the stage clears or I die. After the second cutscene, the maze (third maze found in the game) became totally corrupted. I believe I made it to the banana stage before it went FUBAR. So it appears sometimes the corruption is worse than others (after loading the same ROM many times), but if I play far enough into the game, something gets corrupted. ROMs that seem to work, I just haven't played all the way to the glitch if that makes any sense. So the test ROM bank 0 passed, bank 1 passed, but it hang indefinitely and I cannot return to the main menu without restarting the system and reloading the ROM. Link to comment Share on other sites More sharing options...
Everett1954 Posted December 10, 2016 Share Posted December 10, 2016 Here are my results of various 7800 utilizes on low current draw Concerto cartridge. Here is 7800 Test (NTSC) 20140406[ Video garbage and frozen program Rev Eng Latest 7800 utility cart.bas.a78 Garbled console info screen, program frozen 7800 Utility cart (20150110) Video garbage on console info screen, program frozen. Diagnostic Cartridge Ver 1 (.a78 image) works fine! This is the Atari utility to set the color potentiometer. 7 out of 10 power up I get a blank or distorted rom menu. 1 Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 10, 2016 Share Posted December 10, 2016 Rev Eng Latest 7800 utility cart.bas.a78 Garbled console info screen, program frozen 7800UtilityCart(.bas.a78)_300x150.jpg ^^Mine did that the first time I booted it (see screenshot) but on subsequent tries I got in. Also maybe it's just me, but it's gotten cold recently (for Louisiana anyway) and it seemed the incidence of glitching decreased slightly with temperature decrease. If I didn't have to lug my TV across the house, I'd hook my 7800 up inside the fridge to test this theory. I'd stick it in the freezer for a while to test this theory but I'd be afraid of condensation buildup when I defrosted it. Everette, is that the same Concerto I sent you to test with the "low current" RAM? Seemingly no change on my end... Link to comment Share on other sites More sharing options...
CPUWIZ Posted December 10, 2016 Share Posted December 10, 2016 Toss the system. Link to comment Share on other sites More sharing options...
Andromeda Stardust Posted December 10, 2016 Share Posted December 10, 2016 Toss the system. Why? It works with literally everything else I've ever played on it. Except Robot Tank and Reindeer Rescue... Link to comment Share on other sites More sharing options...
Jinks Posted December 10, 2016 Share Posted December 10, 2016 I think the opposite the 7800 seems to work better hotter. Once you get maria warmed up she does whatever you want her too. It is -33C with the wind chill right now and all I can say is no machine or human enjoys those temps. Link to comment Share on other sites More sharing options...
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