LC475 with Kei-truck style monitor

[Kay K.M.Mods]

This was previously posted on FB's Vintage Macintosh Enthusiasts.
I finished setting up the LC475 the other day and I wanted a 12 ”RGB monitor that fits it.
And decided to build it. I would like to introduce it because it has become an interesting shape.
Read me blog for more details...
https://ameblo.jp/keroxiee1016/entry-12689665077.html
And Kei-truck style LCD builds here:
https://ameblo.jp/keroxiee1016/entry-12689665077.html



It is overclocked and operates above 42MHz. I finished this first.
https://ameblo.jp/keroxiee1016/entry-12680862668.html

 

[Kai Robinson]

Oooh - how did you get the bus speed that high? I thought 40MHz alone was too hit and miss? Have you replaced the clock generator?

 

[Drake]

Spends enough time with fast cars that he decided the computers were too slow!
amazing little project , I know what I'll be doing with my monitors if the guts ever give up.

as an aside I would buy this overclock mod as a kit if ever available, would be a great project.

 

[Kay K.M.Mods]

Oooh - how did you get the bus speed that high? I thought 40MHz alone was too hit and miss? Have you replaced the clock generator?

Hi Kai!
As you can see from the blog (this article was featured in Call-A.P.P.L.E), I'm replacing the PLL clock driver. But supplement it.

This is originally for 12.5MHz input and 25MHz output. although this MC88916DW75 driver has 20MHz input and 40MHz output, there is a margin in the upper limit.
By exchanging this, I raised the clock that did not reach 40MHz to 42MHz or higher, and it is stable without gradually decreasing over time. However, since the serial port does not function normally above 42MHz, it is usually around 41.7MHz.

 

[Kay K.M.Mods]

Spends enough time with fast cars that he decided the computers were too slow!
amazing little project , I know what I'll be doing with my monitors if the guts ever give up.

as an aside I would buy this overclock mod as a kit if every available, would be a great project.

Hi Drake, This variable oscillator is very convenient. Someone said the same thing, so maybe I'm designing a board. I think this can also be used for LC575.

 

[Kai Robinson]

I'd be interested to try swapping out the PLL but fitting a fixed 18.75MHz oscillator for 37.5mHz bus speed - I have the PPC upgrade card, it's clock doubles the bus speed again for the cpu clock, and the actual chip on there is rated for 75MHz.

That, coupled with stephen/drake's 512k 60ns VRAM would make the world's fastest pizza box!

 

[Drake]

I'd be interested to try swapping out the PLL but fitting a fixed 18.75MHz oscillator for 37.5mHz bus speed - I have the PPC upgrade card, it's clock doubles the bus speed again for the cpu clock, and the actual chip on there is rated for 75MHz.

That, coupled with stephen/drake's 512k 60ns VRAM would make the world's fastest pizza box!

This is exciting stuff! 475 is such an amazing little machine, seeing it pushed past the normal limits is quite the thing to see.

I'm genuinely curious to see it perform using Soft PC loading Windows and playing DOS games lol

 

[Kay K.M.Mods]

I'd be interested to try swapping out the PLL but fitting a fixed 18.75MHz oscillator for 37.5mHz bus speed - I have the PPC upgrade card, it's clock doubles the bus speed again for the cpu clock, and the actual chip on there is rated for 75MHz.

That, coupled with stephen/drake's 512k 60ns VRAM would make the world's fastest pizza box!

That's right. VRAM must be 70Ns or higher. I replaced only the Chips. In fact, 70Ns is OK. This is because 70Ns VRAM memory has an upper limit of 43MHz, so it can handle this.

https://ameblo.jp/keroxiee1016/entry-12614308377.html

 

[funwithaluminum]

I am curious about the cool-looking ADB keyboard shown in the photos. Is that something you hacked together yourself, or was that sold at some point?

 

[Drake]

I am curious about the cool-looking ADB keyboard shown in the photos. Is that something you hacked together yourself, or was that sold at some point?

It is a Macway TP-997 in beige/white.
Usually white clicky Alps or Black linear Alps switches. Very nice keyboard

 

[Mac84]

I remember seeing this posted there, I love this mod. Very nice work!

 

[Kay K.M.Mods]

I remember seeing this posted there, I love this mod. Very nice work!

Thx for remember this, Just a using this with the Quadra700 today.