[YamahaDX] converting a Yamaha CX-11 from MSX1 to MSX2

[Alexandre Souza [e-mail] [YamahaDX]]

Hi Everybody!

This is a Yamaha CX-11 (with SFG-01 synthesizer) I just converted to MSX2

Since it is a Yamaha musical computer, I believe it fits here. This is
the "el-much-cheapo" version of the CX5M/II computer

http://tabajara-labs.blogspot.com/2018/07/a-transformacao-do-yamaha-cx-11-para.html

If you take a look around my blog you'll see more Yamaha musical
computers :o)

Greetings from Brazil!
Alexandre

[[e-mail] [YamahaDX]]

That's very impressive!

I'm curious what's going on with the EPROM in this photo. It looks like some kind of hybrid chip.

Loading Image... https://3.bp.blogspot.com/-gl4_lH_BLRI/W1WXpT84wLI/AAAAAAAAW-c/t2-_jrsm0Jg3I5cQXEmCH27csAQswW-swCLcBGAs/s1600/motherboard.jpg

[[e-mail] [YamahaDX]]

That's very impressive!

I'm curious about what is going on with the EPROM chip. Is it a hybrid of some sort?

https://3.bp.blogspot.com/-gl4_lH_BLRI/W1WXpT84wLI/AAAAAAAAW-c/t2-_jrsm0Jg3I5cQXEmCH27csAQswW-swCLcBGAs/s1600/motherboard.jpg https://3.bp.blogspot.com/-gl4_lH_BLRI/W1WXpT84wLI/AAAAAAAAW-c/t2-_jrsm0Jg3I5cQXEmCH27csAQswW-swCLcBGAs/s1600/motherboard.jpg

[Alexandre Souza [e-mail] [YamahaDX]]

That eprom chip is a curious thing. This is a ceramic subsstrate with a
pair of 27128 PLCC EPROMs and a 74ls04 inverter hex chip. It efectively
simulates a 27256 chip. Nothing else. Why it was used in place of a 27256 I
cannot understand...

Post by ***@jps.net [YamahaDX]
That's very impressive!
I'm curious about what is going on with the EPROM chip. Is it a hybrid of some sort?
https://3.bp.blogspot.com/-gl4_lH_BLRI/W1WXpT84wLI/AAAAAAAAW-c/t2-_
jrsm0Jg3I5cQXEmCH27csAQswW-swCLcBGAs/s1600/motherboard.jpg

[[e-mail] [YamahaDX]]

Maybe the 27256 wasn't available at the time? Or maybe it was, but only at outrageous prices. Memory pricing can be very quirky.

I smiled when I saw the Z80A. I used to have the Sinclair ZX81, then the ZX Spectrum, so I did some Z80 assembly language programing, as a teenager.

- Andy

[Alexandre Souza [e-mail] [YamahaDX]]

I still have my ZX81 and Speccys. I've got the rubber, plus, +2 gray, +2
black and +3 :)

[[e-mail] [YamahaDX]]

Cool. I just had the original rubber keyboard one... I'm fairly sure it was the 16K, because the 48K was far more expensive.

I sold my ZX81 to fund buying it, which made me very sad, because it took months to actually get one when they were first released - which I had no idea was going to happen, of course.

- Andy

[[e-mail] [YamahaDX]]

Me too. I have ZX81, a 16k and a 48k Spectrum, a 128 (my favourite), a +2 and a +3. Not to mention two huge boxes full of cassettes, joysticks, interfaces, and ROM cartridges. You can say I am a bit of a fan lol. I don't use any of them, they are all in storage but I won't part with them for anything.