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FALCOR4 last won the day on August 17 2019

FALCOR4 had the most liked content!

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    Chopper Commander
  • Birthday 02/27/1958

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    Tinkering with the 99, air rifle collection, off road motorcycling, enjoying the grand kids!

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  1. That works! I did a curve trace a year or so ago with a 1N34A and an NTE109 just for kicks. The downside to germanium diodes, though, is that the leakage current is generally higher than silicon. 1N34A_NTE109 Comparison.pdf
  2. I've always used germanium diodes because the voltage drop is less than that of a silicon diode. 1N34As I believe? It's getting hard to find good ones; the ones from China are all over the board on a curve tracer. There are some good diodes that come out of Russia you can sometimes find on EBay.
  3. @Ksarul, if your 1983 copy is the one I sent you I believe that it was missing a page so this you'll be able to go into WHT to add it now? Good deal! Thank you @matthew180!
  4. Hmmm, interesting thought! I've never looked at it that way. The 1M partitions are defined in the LSbyte of the register WORD so you could use that to track/set virtual 1M cards? Maybe a short routine in SRAM or cartridge space to swap them back and forth. Lots of possibilities on how to use it.
  5. Rich, I don't know if I am answering your question correctly but I'm willing to take a stab at it. For a 32M SAMs, it would take 8K of WORDs to define each 4K memory page along with another 8K WORDs to define where in the TI memory map each 4K memory page would be found. Check my math! 😁 Of course, to complicate things, that's only if you assign one 4K block to one TI memory segment! You could have the same 4K memory page show up in multiple TI memory segments, there are uses for that I suppose. BTW, I don't personally believe that we will see a SAMS card any larger than 16M because that is the limit for the LS612 chip. It would take some rework to go any higher than that. In emulators and in RXB, I totally got it. I have a few 4M cards and I don't know how many others are out there in use right now. 1M may remain the gold standard card for a while if not for quite a while, IMHO.
  6. The 8 bit address captured by the LS612 can be read back and you will get the MSbyte of the last write to that register. But, on cards larger than 1M, the latch for the 4 bits of the LSbyte cannot be read back because the latch is not wired to read back on the data bus. So, what happens is that you will get a "copy" of the MSbyte that was loaded into the register which may not be (and probably isn't) what was loaded into the latch. It's confusing. Say you wrote a >0100 to a register. If you read it back you will get >0101 on any SAMS card. The LSbyte read back is simply a copy of the MSbyte from the LS612 and not the latch. This means that software must be aware of register write addresses if it is necessary to keep track of the addresses.
  7. Thank you Lee, spot on. With the 1M and smaller cards, when you execute a register write, the LSbyte is written to the LS612 but when the TI next writes the MSByte it overwrites the LSbyte that it just wrote which makes the LSbyte of the WORD irrelevant. That's why it really doesn't matter what you have in the LSbyte of a WORD that you write to the SAMS card if it is 1M or smaller. However, it does matter with the 4M card (and any other larger increments that may come along), which has a separate latch that captures the LSbyte of a WORD that is written to the registers. That's why it's recommended that software assumes a larger card and to be fully compatible with any SAMS.
  8. I've had good luck with JB Weld Plastic Bonder #50133. Found it on Amazon and at Auto Zone.
  9. I've been using the Wathai 110V 115V 120V 220V 240V Brushless Fans <80mm x 25mm> from Amazon. They're an easy replacement and are about (subjective here) half the noise of the OEM fan.
  10. You might try nylon screws, washers and nuts. I bought a bag each off of either EBay or Amazon a couple years ago and they work great. I purchased the bolts a bit longer than they need to be so I can clip them down once installed. The silicon pad, probably used for the 7912 to electrically insulate the heatsink since the tab is at -12v, IIRC?
  11. I'm with you on that! Test points along with Ksarul's PEB extender board would make troubleshooting much easier.
  12. The HRB4000B is a PEB card and not a sideport attachment but, if you wanted to use it you could split the card into two (two CRU addresses), use one as a RAMDISK and then put your custom DSR into the other. You would have 6k of writable DSR space (actually 12k if you want to "trampoline" between two pages) and you would have access to half of the memory that is on the card for apps/etc. Just another thought for the heap.
  13. Looks like one of the older PEBs with the push button switch. Not sure why the P/S is pictured as removed? May want to ask the seller, one possibility is that it has been modified with a different P/S? Also, not sure about the console keyboard. I know that most Matsumi keyboards are beige but I have one console with a black on and the console in the listing looks to be one of those? Can someone else more familiar take a look at it? If it is, also ask the seller if each and every key works properly. Cost wise, not counting outliers, $250-$500 range. This one looks clean/complete and includes the console, joysticks, etc. so it could go for an upper range $$?
  14. Also, the QI I/O port has silver grounding fingers. Useful for a quick check.
  15. This is from Michael Bunyard's Hardware Manual regarding the cart port: TI99_4A cart port info.pdf
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