V9938 to v9958 adapter?

By PingPong

Prophet (3460)

PingPong의 아바타

26-10-2019, 21:38

I wondering if it is possible to make a kind of small adapter board with a v9958 on It and some kind of small wires ( like that ones that connect vdp wait signal) that can be used by plugging in a V9938 socket after cutting the original chip and soldering a socket in place of vdp

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By Omega

Master (213)

Omega의 아바타

05-11-2019, 01:08

Sure, should be no problem.

By gdx

Prophet (3090)

gdx의 아바타

05-11-2019, 10:00

Yes, but is it really useful? There are only 2 or 3 wires to solder to change the VDP, and then an adapter may not fit in all MSX2. I think just the socket is necessary.

By PingPong

Prophet (3460)

PingPong의 아바타

05-11-2019, 16:43

the idea was to simplify the replacement:
- cut the older v9938 pins
- solder the socket
- plug the adapter
- connect the WAIT pin to z80...

By Wild_Penguin

Hero (555)

Wild_Penguin의 아바타

05-11-2019, 18:58

Having done an MSX2+ upgrade, there is little point in an adapter IMHO. I mean, there are like 3-4 jump points to do! And perhaps a few resistors needs to be removed (I'm not sure about all models, and this needs to be done irregardless if you have a adapter or not).

Compared to these steps, removing the old VDP and soldering a socket in it's place is going to be waaaay more work (and dangerous) in any case. So it makes little sense to make an adapter board just for skipping these few points. See any MSX2+ upgrade guide to see what I mean.

Also, an adapter board will just introduce more non-soldered socket connections, which is always a weak point in principle (well, unless you make an adapter board which solders straight into the motherboard). Also, as gdx pointed out, an adapter will introduce more height (which, as already stated, might prevent using one in any case; remember the VDP is supposed to have a heat sink, too...).