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About helocast

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  1. No problem, Ksarul. I probably should've just posted the whole clean 516-page PDF for anybody else researching chips of the era (it's a huge one): Fairchild_MOS_CCD_Data_Book (1975).pdf
  2. Here's the specs on your F4049BPC compliments of 1975 Fairchild Handbook. I also have several tubes of the 1052911-X if somebody is doing a group project. Doug
  3. I know there's tons of calculators online, but this has always been my go to for supply lines (had to find the website again). https://www.mclpcb.com/pcb-trace-width-vs-current-table/
  4. Not the best copy I've seen, but maybe this will help y'all fill out a few of the missing ones. I checked a few and they seem to match off the list CD+four digit number of TI's part number. Doug
  5. For this one specifically and to a couple previous posts: Again I have visually identified (desoldered the female GROM riser on a a dead QI board) and those two traces fly by the port without connection, unlike the earlier 4A. Not to raise what I believe a (possible) separate issue to explain the FG's behavior on a QI, but imho I really feel it is more related to how the 4A generates Vss pin 33 on the grom connector vs "real ground" as the QI is wired. What I can't explain yet is why the ~ -.7v bias difference still works on QI built-in groms interchangeable with 4A groms. I really hope I'm not following the wrong rabbit down the proverbial hole on this research.😅 Doug
  6. You're pretty close from what I've been able to deduce all these years focusing on Figure J of the QI schematic. Despite how it is drawn, the open collector pullup on GRDY does go to all three groms (physically checked best my eyes can do on a populated motherboard). I keep meaning to publish all the oops! I've found so far, but don't really have the software to make a professional presentation here to the collective. Way back when Tursi pointed me to the Hombre TAL stuff on WHT it became one of my main projects. CPURY is a fairly complex equation taking GRDY, GCS, and SYSRY into account driven/sampled on @CLK2 phase and then finally NANDed with three separate conditions off of the shift-hold 8/16-bit bus conversion logic circuit. Hombre Logic TAL004 Gate Array.pdf
  7. Yes, pin 4 -CRUCLK and pin 6 CRUIN have no motherboard connection to the GROM port/riser. Just happens I've been spending the past month going over trace/component by trace between both models for a project. What I have not been able to detail on the FG99 because I don't have the schematics is the use of Vss, GROM port pins 33 & 35 (the odd little -.72V used to pull the line slightly below system ground). The standard TI-99/4A used a cap, resistor, and diode to provide that, but to "save" cost didn't make the final QI design and they just tied both pins 33/35 to ground. I know in Ralph's own troubleshooting he noted the FG99 is doing what it is supposed to, minus making final menu visible/actionable. These are really the only differences between the GROM ports unless you want to discuss the way pin 1 RESET is realized between the two, but that doesn't apply here. I have to assume TI engineers kept timings identical between revisions, but we know GROMs are very poor drivers because of the single transistor managing both pull up and pull down on its data lines. I throw something together in the FG thread whenever I get this little project of mine finished. Doug
  8. I guess I should've sent this zipped when you bought my FinalGrom99 ... didn't think about it at the time. Consider my PC hard drive like the Wayback Machine when it comes to TI stuff, even though I never use 99.9% of the files I get/find through this forum. I snapshot'd this back on July 12, 2017, at least that's what the file(s) creation date tells me (well prior to the existence of Ralph's current updates folder published 13 months? ago). Maybe it contains the originals required (not responsible if people break things). As to "building" the cpld file, there seems to be instructions at the end of the README.md file but it's all alien👁️‍🗨️ to me. Hopefully it helps someone. Doug finalgrom99-master.zip
  9. helocast


    Ebay funkward-tech https://www.ebay.com/itm/TI-TMS9901NL-TMS9901NL-40-TMS9901-Programmable-System-Interface-DIP-40-x-1pc/151076609192 has always been reputable to me. Only had one order out of probably two dozen where I was physically shorted DRAMs, but they made it up. I've had zero fakes in my dealings, but I'm about due. Doug
  10. Appreciate the offer. PM'd OLD CS1. I'll keep my reply short since I'm in Dev. I really wanted it to work ... if nothing else to have a piece of every tech offered here. I can't keep up, but retired pension/money permitting I try. Doug P.S. Brewing Academy on Ebay still swears up and down this combo "works" and I've sent them a message to alter their listing in that regard. ¯\_(ツ)_/¯
  11. Considering I only run/own V1 QI, I'm still wondering what to do with my FG purchased early in 2018? Can we get credit/trade-in against a future SDD99 sale if that will finally support the QI? Doug
  12. A little slower, 55ns vs 45ns and wider voltage supply range. Other than that it is also in the 44-pin TSOP II package. $6.92 AS6C8008-55ZIN https://www.mouser.com/datasheet/2/12/AS6C8008-1288432.pdf I haven't checked compatibility any closer than that. Doug
  13. It's Quora, which I give about equal footing on the level of Wiki for delivering dependable answers from "experts", but: https://www.quora.com/Some-powersupplies-can-be-switched-between-110V-and-220V-Will-leaving-the-switch-in-the-wrong-position-damage-only-the-powersupply-or-also-anything-connected-to-it#:~:text=If the switch is left,power supply or device results. Doug
  14. 👍Looks like you're progressing ... always good. I just wanted to address terminology in my last "help". Thierry does theory WELL (as do probably most of the seasoned contributors here). I know enough to be dangerous, but I always try to consolidate links, pics, sources since projects and references also seem to be scattered to the four winds over the years. With that said, http://www.harmlesslion.com/text/atx_peb.htm seems to be the project you are following. Might I also suggest Chris (Shift838 here) as a source since I know he did a great write-up on solving all of this AND putting PEB cage in a modern PC case. What I observe: It looks like your PSU has six rails supplying max peak of 750W. If you "math" what each rail could provide max, you get 823.6W, yet you are still limited to any combination of rails not totaling PSU rating of 750W. TI spec'd/budgeted original supply to not more than ~4W on unregulated +8V rail to include a floppy drive, ~3.75W on unregulated +15/16V rail to include a floppy drive, and finally ~4.5W on unregulated -15/16V rail? Divide each of those rails up among 8 PEB slots plus a drive respectively and you can see there wasn't a lot of excess power and why only one drive was officially supported - actually quite puny! I'd suggest keeping your two yellow +12V rails separated, one powering backplane and one powering noisy accessories (fans, drives), common grounds. I don't know what your full complement of cards and accessories for your system are. I'd also suggest using the +5VSB rail (see attached picture as an always-on source for a TIPI if you have one and perhaps a standby panel light. Thinking aloud: I personally can't see how a modern PSU provides enough overhead for the relatively power hungry 7805s or 7812s of the day. +8V was chosen to provide 2.5-3V overhead just as the +16V was chosen to provide 3.5-4V overhead to respective regulators. Also of course over time, some users/techs may have bypassed regulators on individual cards to control heat and chose to supply regulated +5/+12/-12V. If they did that they should have annotated on the card/shell that was done to prevent plugging in a modified card into an unmodified PEB. I guess it has been successfully done, so I'm not trying to impune anybody's successes previously. As I said, I just try to consolidate and combine info into a one-stop reference ... and those aren't all that pretty (tough conveying all the information and I suck at that). My 2 cents. Interested to see how this turns out and as always, good luck and low magic smoke release! Doug
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