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rkrenicki

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About rkrenicki

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  1. I just received another Non-QI TI99 in the mail. It is pretty beat up, but it does function. I have not had a chance to open it up and socket the ROMs yet. I may actually go though and socket everything and use this as a testing reference while I am at it.
  2. Yes, /ROMEN, /MB, and /WR all have normal looking waveforms. I went through and probed the rest of the lines, and it seems that Non-buffered A3 and A4 may have an issue as they are staying mostly low. I started pulling chips one at a time until I saw normal strobing on those lines, and it looks like the U610 ROM may be the issue here.
  3. Alright, I think I can safely rule out a clock problem. Both with a new 0.33uH inductor and the old-stock inductor, I get a solid 2.99964MHz clock on 4 phases, both normal and inverted. I tried one of my other TIM9904's and also got the same clock exactly. Phi-0 /Phi-1 I am going to socket the RAM and ROM on my QI console sometime this weekend, to that I can test those chips. They are still big question marks to me right now.
  4. Why, 1.21 Jigga-watts of course. I did put a copper pour keep-out area around these parts for future revisions. I also removed the values, so I can make a little grid of values nearby detailing the 9904/9904A use. So, just to be 100% clear: You are using a TIM9904/74LS362 with a 48MHz Crystal, 3.3uH Inductor and a 22pF capacitor, and that works for you? I am trying to find a datasheet for the non-A version of the TIM9904, but I have not yet found one...
  5. Okay, that is good news. I have corrected the schematic (and therefore the silkscreen) to reflect 0.33uH. I have the correct 22pF cap (already installed) and a 0.33uH inductor on hand. Since neither of these parts are tied to ground or 12v, I cannot imagine that the board capacitance would play too much of a role here, but I can try doing a keep-out zone underneath them on the next revision. I do also have 0.33uH new inductors to try, which I have not done yet. In related news, I also tried some other TMS9900s, TMS9901s, and TIM9904s that I had on hand. The only ICs that I have not yet tested in another machine are the ROMs and RAM/SRAMs.
  6. My original part is actually an open wound inductor. I had no color bands to go by. L602 and L207 are the only parts that I was unable to reconcile a value from the actual donor board, but yes.. there are a number of inconsistencies which I corrected along the way.
  7. The entire design will be available freely, including the gerbers and the BOM. I am not really planning on selling any significant quantity of these, but anyone would be able to have their own made up with whatever options they want (gold fingers, ENIG, fancy colored soldermask, etc) In order to distribute 3 different power rails and ground on a 2 layer board, then bus bars or jumpers would be needed. The 4-layer gets around that need. That is a good point, I was unsure on the value for that location. I see 33uH on the TI schematics, but the HackMac schematics say 0.33uH. The QI version of the schematics say 3.2uH. What value are you using for that inductor? In the meantime, I will use the one that I harvested off the original and see if that changes anything.
  8. The design will be freely available, but I can have some fabricated for sale once all of the dust settles. At this stage, the video output type is not changing. I will try to implement any improvements once I get to that stage. Otherwise, I did try swapping in all of the original LS logic with no change. I also swapped the CPU with a spare, also with no change. I am going to open up my QI console and socket the SRAM, ROM, and GROM chips so that I can test these.
  9. Yes to the 48MHz crystal. I apparently forgot to order a new one, so the crystal is the original one from the donor machine, same as the TIM9904. I did have this thought as well. I largely have HCT and AHCT chips in my stockpile here, so I figured I would give them a try. I do have the original LS chips from the donor, so I will be trying to swap those in one at a time. I assume by "Tulip" you are referring to Turned Pin sockets? This has been a long debated topic about which is better, but I personally prefer Dual-wipe sockets, and I know how to properly prep pulled ICs. I do stick with name brand sockets though.
  10. Surprise second update in one day. I finished installing the rest of the parts today, powered the board and checked voltages. Everything looked good. I then stuffed the board with all of the ICs. I used new parts wherever I could (except for the 244/245s, since I can't find my tubes of those parts at the moment). First boot: I get a video sync, and the random tone from the SN94624, but it fails to actually start. I probed around the Address and Data lines, and I see activity with nothing obviously wrong. The bigger problem I think is that my donor machine was of questionable origin.. and I never powered it on prior to stripping the board. I honestly cannot say for sure that the custom chips actually work, so I may be dealing with one (or more) bad chips here. My known working TI99 is a QI unit, so that is of limited use here. I did buy a few of those "TMS9900 Chip Kits" on eBay from China, so I will try swapping parts around to see if I can get it to boot.. but I do not have extra 4116s, GROMs, or ROMs. In the meantime, I am going to find another non-QI TI99 so I have a "known working reference" board to compare against.
  11. Due to a recent death in the family, progress on first revision testing has been slow. I do have most of the passives and sockets installed. I did find a couple of errors in some parts values on the HackMac schematic during assembly. Nothing too crazy, just a couple of transposed numbers. I also did find a couple of errors on the solder mask as well, which were artifacts from the Gerber import from sprint. I thought I found them all before sending off to fabrication, but it looks like I missed 3 or 4 of them.
  12. Yea, it was something far more common in the 70s/80s. Pretty much everything now will just use a 3 digit code for a non-polarized capacitor. There are a good number of these "green apple" colored caps scattered across the board. Pretty much anything that is not a 0.1uF cap or polarized is in this form factor. All of the 0.001uF keyboard/joystick bypass caps below the VRAM are like these, intermixed with the pull up resistors. What really gets confusing are the "Crayola flesh colored" axial parts are caps too. The only thing TI was consistent on, was their inconsistency.
  13. I know this is an old post, but someone pointed me in the direction of this thread. Those two light green parts are indeed capacitors. They use the same color coding system as resistors, but they are *not* resistors. C100 is Blue, Green, Black, Gold, Black which works out to 56pF C101 is Brown, Red, Black, Gold, Black which works out to 12pF These values match the schematics as well.
  14. I did find a number of inconsistencies on the original schematics, but nothing too crazy. Mostly reference problems. I found more issues on the HackMac KiCAD schematics that I "started with".. there were a large number of problems with that. It really would have taken me less time to lay the whole schematic myself than to hunt and fix all of the errors. On my motherboard, C100 and C101 matched the schematic. They "look like" resistors, but they are absolutely capacitors. The light green is sort of dead giveaway. C100 is Blue, Green, Black, Gold, Black which works out to 56pF C101 is Brown, Red, Black, Gold, Black which works out to 12pF These values match the schematics as well.
  15. Let me start of by saying.. I may dream big, but I am not talking about adding Wifi/Bluetooth/etc. At that point, you might as well just run an emulator on a Raspberry Pi, which is very much "cheating" in my opinion. Using an FPGA to emulate cycle-accurate versions of old chips is as far as I would be willing to go. Anything beyond that is beyond the scope of what I am trying to accomplish here. The only real exception to that would be the video system, since using composite video or Analog RF video is getting harder and harder nowadays. I am perfectly fine with a potential VGA, but DVI is okay too.
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