Convert EII to EII +

[dfiorucci]

It even still has the stand offs for the piggyback board same as mine.

[Electro disco club]

Mine is serial 1160 i think. I had never seen the jumpers setting to upgrade memory.

I have the main 2.1 eprom.

[dfiorucci]

The jumper settings are between IC10 & IC11
256k = W1 & W4
64k = W2 & W3

I wired toggle switches to switch the connection for W1 W2 and W3 W4
So I wired the one that goes W1 or W2 to one switch and W3 or W4 to another switch.

[Electro disco club]

Okai okai.

I've order tms4256 150ns on eBay. I've checked th? digital board S/N ans it is numbered 880!.

I have the eprom 2.1 main but I Saw on EII+ pictures from th? forum that's main 2.1EII+ printed on the eprom. See bushing conversation

[Electro disco club]

I will never never sell my EII ! My children will play with it on 2049.

[dfiorucci]

My understanding of the Main boot rom is that 2.1 no matter how it is labeled is truly the same.
So the Main 2.1 works for all versions.
I checked two bin files one labeled 2.1 and the other labeled 2.1+ and they where identical.
My order of extra KM41256AP-12 came in yesterday going to have another go at this.

It might be that earlier version of the plus where only compatible with the 150ns chips since that was the speed of the 64k variety.
They may have changed a resistor value capacitor value or one or several chips to get the timing right for using the 120ns variety drams.
I have 16 pictures sent by Alpha maybe I'll be able to find a clue there.

[dfiorucci]

No success today with the 120ns 256k drams so I ordered some 150ns 256k drams.
It may just be a timing issue for my particular Emulator II.
Hopefully I will have success next weekend t get this to an Emulatator II+.
Have my fingers crossed.
I was able to verify that there is no difference in chips that are left empty between the EII and the EII+ when both have the Rev 1 digital board.

[Electro disco club]

WE crossed th? fingers yeah.

I have ordered Texas instrument 150ns..

EII + or EII - ?

[dfiorucci]

What chip do you have at IC11 on the digital board.
All the pictures I've seen so far of the EII+ has a CD74HCT138E by texas instruments in them
Mine has a 74HCTLS138N I can't seem to find any exact information on the one in mine but I know they are of the same variety Line Decoder/Demultiplexer Inverting and Non-Inverting but they could have different output combinations and this might be the difference.

[Electro disco club]

It is a CD... on mine

[dfiorucci]

Also check IC98 it should be the same.
This might be why the upgraded memory is not working for me.
Sounds like a Mouser order in my near future.
Thanks,
Dana

[dfiorucci]

Unless the chips that I have in IC11 and IC98 are just an off brand that is labeled different I may have found the difference between the regular and the plus models along with the 256k drams of course.

[Electro disco club]

It's a CD again.
! Maybe it IS a Good news

[Electro disco club]

Hy!
I wonder what did you use To make the jumper setting? What kind of harness?
Do you have To solder behind the digital Board( removed the Board... ) Or solder simply above the Board?
I dont receive yet the DRAM..
Thanks

[dfiorucci]

Just two jumper wires on top is all you  probably won't have to pull the board to solder them in.