broken video chip TMS9129 replacement

Rookie (21)

29-03-2023, 22:52

I have a broken video chip TMS9129 in a Frael Bruc 100 MSX. Is a italian version of MSX.
The TMS9129 is very expensive and hard to find, can i replace with TMS9929A?
There are difference of video performance?

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Por Jipe

Paragon (1625)

30-03-2023, 12:07

it's not possible because they don't have the same memories
the 9129 has two 16k x 4 bit
the 9929 has eight 16k x 1 bit
look at the VG8010 and VG8020 manuals to better understand

Por Repair-Bas

Paragon (1176)

30-03-2023, 13:47

I have almost all msx parts in stock.
the 9129 is in stock

Por mjnman

Rookie (21)

30-03-2023, 21:32

The page https://www.msx.org/wiki/Philips_VG-8020 says "Texas Instruments TMS9929A or TMS9129NL"

Por АIеks

Paladin (983)

30-03-2023, 21:47

TMS9929A and TMS9129NL differ significantly in memory handling. Direct replacement is not possible. Perhaps the link is inaccurate information or there were modifications.

Por Accumulator

Champion (351)

30-03-2023, 23:19

Aso Tms9918, TMS9919 are 50hz and TMS9929 is 60 hz , as far as I know

Por gdx

Enlighted (6442)

31-03-2023, 01:47

Accumulator wrote:

Aso Tms9918, TMS9919 are 50hz and TMS9929 is 60 hz , as far as I know

No.
https://www.msx.org/wiki/Texas_Instruments_TMS9918

Por Jipe

Paragon (1625)

31-03-2023, 14:16

are you sure it's the VDP that's broken?
did you try replacing the VRAM memory first?

Por mjnman

Rookie (21)

31-03-2023, 22:49

yes. I'm sure because I replaced this component with TMS9129 from VG8020 /40 and the Frael MSX work.
The TMS9129 from Frael in the VG8020 have black screen. (double check)