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AwkwardPotato

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Posts posted by AwkwardPotato


  1. 10 hours ago, AtariNostalgia said:

    I guess it needs recapping?

    Probably not. Check that the wires from the power input at the back of the computer are actually attached to the internal power supply, and that there's continuity between the internal power supply and the motherboard. Also make sure that the power switch is good; it is known to fail.


  2. 7 hours ago, mizapf said:

    Correct! How did you know?

    I couldn't think of any other TI hardware with 4116s on it (besides the motherboard, but it doesn't look like what's in the picture). Also the black silkscreen on green soldermask, the only place I can remember seeing that is on the PEB cards.

     

    I'll let somebody else go after me since I posted a picture only a couple days ago :)


  3. Try applying new thermal paste on the stock RF shield/heatsink and see if the problem goes away. If the system still acts up afterwards, there's a good chance that the 9918A is failing (chips aren't always completely non-functional when they're damaged).

     

    If a VDP can't stay stable even with refreshed thermal paste on the stock heatsink, it's a better idea to replace it than cut up the shield/install heat pipes/custom heatsink, since the problem will likely only continue to get worse.

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  4. Black screen w/ constant noise is a pretty common TI failure mode. First thing to try is pulling GROMs CD2156 and CD2157 and seeing if that changes anything. If there's no change, the fault most likely lies in one of the ROMs/SRAMs (the four wide chips right next to the CPU).

     

    Unfortunately neither the ROMs nor SRAMs are socketed, and there really isn't a good way to narrow down the problem without a logic analyzer or oscilloscope. Replacements for the SRAMs are easy to find on eBay, but ROMs would either need to be programmed yourself or harvested from another board.


  5. Agreed with wierd_w, it's a good idea to make sure it's not the TV before swapping chips. Pretty much all the computers from the time period were slightly-out of spec with their video signals, so the one you have might not display anything with the TI despite working with the C64. It's an especially good idea to rule out the TV first when dealing with the TI though; the "black screen" issue can be caused by a number of components (CPU, 9904, SRAM, ROMs, etc.)

     

    One question: with the sound chip installed, do you get any kind of noise when the computer is turned on?


  6. 7 hours ago, Tim Hamilton said:

    I get black vertical bars and no color on the screen.  I've read it could be the VRAM chip that needs to be replaced, but another site describes replacing the crystal for the same symptoms.  Which is more likely?

    If you're able to see the title screen behind the black bars, but with no color, it's almost certainly a crystal problem. For something like that I see no point in buying another console; the crystal only has 2 pins and would probably take about 10 mins to swap.

    • Like 1

  7. On 6/21/2019 at 9:00 AM, tater1337 said:

    I really doubt this, just that the commie guys must be congregating somewhere else

    Agreed, there are more Commodore/Amiga forums than I can keep track of. The Apple folks have quite a few too; it's more just that us TI'ers don't have our own active forum outside AtariAge.


  8. I see. Well, what games do you guys suggest for us to get, that are common or relatively common?

     

    The TI has a really nice port of Q*Bert. It seems to be moderately (?) common, but prices for that one can be a bit on the high side for TI carts. Parker Bros. also made ports of Frogger and Popeye for the TI, but I haven't played them so I don't know how good they are. Lastly, while not a game, if you ever get ahold of some kind of disk system (PEB, NanoPEB, etc.) Extended Basic is a really useful cartridge to have.


  9. I was recently given a Beige desktop G3, and so far it works great, but then I've only had it for less than a week. So what exactly makes them a pain? Just curious as to what I'm in for?

     

     

    The G3 Desktop's case (which it shares with the 7x00 series) is notoriously brittle. It's really easy to break little plastic tabs and other parts even if you're really gentle with it. Pretty much any Mac from that time period suffers from the same problem though, although the G3 Minitower seems to be a lot better than the Desktop in that regard.


  10. I can do TI repairs and have done them before, although I have very limited free time so I don't do them often (yet). And as Opry99er said above, it might not always be worth it when consoles are so readily available. However, the most common points of failure in my experience are the VRAM, ROM, and SRAM, in that order. VRAM and SRAM can be found on eBay as loose chips or pulled off spare boards. The ROMs can also be found on spare boards, or you could burn your own on EPROMs. Unfortunately loose boards don't come up often on eBay, but occasionally small lots of untested boards will come up. More frequently, you can find a lot of 3-5 untested consoles with beat up cases instead.

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  11. I've got a few old Macs too! My favorites are probably my SE and IIx; both are rock-solid, fast, and really nice looking (the mid-late '80s Snow White design language is classic).

     

    My next machine will hopefully be a Mac Performa 6360 or a beige G3 Tower.

     

    The Beige G3 is a really nice machine, and I highly recommend it (the desktop model is annoying to work on, but I used to own a tower model and it was great). I have mixed feelings on the 6360 though; it's faster than its 6200 and 6300 predecessors, but like them, it has a really brittle case and working on them is a pain. It seems pretty difficult to find one that isn't missing half the plastic pieces too.

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