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?

ログイン/登録して投稿

By Jipe

Paragon (1614)

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

By Repair-Bas

Paragon (1175)

30-03-2023, 13:47

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

By mjnman

Rookie (21)

30-03-2023, 21:32

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

By 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.

By Accumulator

Champion (334)

30-03-2023, 23:19

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

By gdx

Enlighted (6213)

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

By Jipe

Paragon (1614)

31-03-2023, 14:16

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

By 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)

By mjnman

Rookie (21)

20-04-2023, 14:50

I tried use a TMS9929A and the image is broken:

with a TMS9129 now it's correct:

The VG8020/00 use the TMS9929A but the VG8020/20 or 40 use TMS9129

By Grauw

Ascended (10768)

20-04-2023, 15:17

The TMS99xx and TMS91xx differ in whether they use 1-bit or 4-bit DRAMs, so you gotta use the appropriate one for your motherboard.