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wietze

Ti99/4a + 32kb rom + FinalGrom99 = Lot of Blue screens (hardware failure?)?

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4 hours ago, wietze said:

Asmusr pointed me out in PM that I have a TMS9929NL chip, which is lacking the `A'. Which in turn implies it does not have support for the bitmap mode.

I hope that I can just replace the TMS9929NL chip with a TMS9929ANL chip then!

 

If you don't have a spare lying around, PM me with your address (assuming you are in the U.S.) and I'll mail the used one I pulled out of my system a few years back... if you don't mind having to straighten a few bent pins.

 

CHIP.thumb.JPG.a53c9264951cc57217017f97a0006599.JPG

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1 hour ago, atrax27407 said:

A TMS9918ANL is NOT a replacement for a TMS9929ANL.

 

Crap, obviously I wasn't thinking.  29 is not 18... DUH!  Well, they say Senior Moments are not bad... unless they all run together.

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On 12/7/2020 at 10:53 AM, wietze said:

Just opened her up, and it seems to have a TMS9929NL vdp chip.

I currently connect the machine to the display using a `Texas Instruments TV PAL Encoder PHA 2030'. 

 

Could the use of a PAL vdp chip cause the abovementioned graphical behaviour with some programs? 

(Edit: some thread in this forum suggests that all cartridges encountered are PAL/NTSC compatible; so I assume answer is `no').

How come there is a wrong VDP inside your console? The non-A variant should only be in the TI-99/4, I should have expected.

 

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On 12/9/2020 at 6:11 PM, mizapf said:

How come there is a wrong VDP inside your console? The non-A variant should only be in the TI-99/4, I should have expected.

 

No idea, this is how I got it.

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I replaced the (non-A) VDP with a TMS9929ANL. And now the machine displays bitmap graphics.

 

Awesome! This resolves the issue I had. Now I can play all the nice TI games to my delight!


Thank you for the help.

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