EIII Keyboard : missing IC 27 chip on the cpu Board > looking for JEDEC data!

[artbylaw]

Sounds good Alan - it will be much appreciated.
While your at it - if you could somehow give me the order of how those 5 boards stack up, that would be a load off my mind. I'm not quite sure the previous owner cared to put them back correctly (or whichever friend he had working on it) because they weren't exactly "pushed in" all the way when I first opened it.
Also, those chips - you can just pry them up - correct? There's no soldering holding it?

[Alan EIII]

Yes there is no soldering
Ic are pushed in sockets.

I use a probe stick to gently lift both sides.

Some use a ic extractor but I don't have any at home.
I tried to use one at work but it is time consuming for a 20 pins IC.

[Alan EIII]

Unfortunatly I did not had news yet from the person who proposed me the data for the ic27.
Summer is nearly here so we have less time digging into our devices.



As some proposed me, I would be very gratefull if someone could lend me the chip or board for a week.
Of course I'll cover all the expenses from the start via paypal.

thanks in advance.

[mg73]

Hi,

Any  more news on this exciting matter?

I have three non working EIII right now
quite sure that there is problem with some PAL´s on the CPU boards
send two of my  CPU boards to Niko at Studiorepair.de
for repairing but havn´t been able to get hold of him over a month
and his website is down,hope I don´t lost them forever.

But if there is any data available yet for the PAL´s IC1, IC10
i can reprogram there ones i have on the third CPU board
i have to get one EIII up and running.

[Alan EIII]

Hi everyone

First :  thanks Artbylaw who lended me his chip.


Well... it's not going as fast as I tought it would be... there could be a protection somewere...

the first attempt looked fine, the copy was done in ten minutes.

But when we tested the data using a simulator it comes up with an error-
I could have tested the new chip in my EIII but it is sure that it will not work and I don't want to test the original chip in my EIII as there could be other issues on my board.

After several attemps using different chipreaders it always ended with the same error.

Could it be a protection?

I don't really know but the only way to be sure it to run a live analysis:

I have to send signals to every inputs of the chip and to monitor the outputs.
that will give me what is called a "table of truth", using that binary data I' should be able to rewrite the missing jedec data;
you can see an exemple here : http://flipprojets.free.fr/AlvinBSMT_E.html

note mg73 :: the technique will only work with a few chips : they must be combinatorial only (I'll explain later)
I have to check that the IC you need are registred or combinatorial.



I builded the test tool(pretty simple, but must be clean:  a 5v psu; an 20pin ic base; 10 switches & a multimeter)
now I have to test the 1024 combinaisons! (lets say 100 a day)
I could build something like this http://cgfm2.emuviews.com/pal/index.html but I'll have to post my reply next christmas...

I hope I'll post my results in a few days...

[mg73]

Great work you doing!!

On the CPU board there is 4 PAL´s
IC 10,IC 27 that are 16L8A
which are combinatorial and should be ok

IC 11,IC32 are 16R4 and are problematic,right?

Is there anywhere to get this as spare parts?
I don´t think I´m getting my back from that service guy in Germany
been trying to reach him over a month now.
Does anyone know him here
NIkolaus Riehm at studiorepair.de in Bad Homburg.

[artbylaw]

No new news in a couple months now, Alan....how's the work coming?

I didn't have any success testing out the power supply myself.
 I'm just going to take it to some people that have worked on a few things of mine in the past.
I will need that chip back to see if it fully comes back to life.
When do you think you'll be done with it?

[oe8ueuur]

OK, it looks like I'm needing to replace the capacitor for C-49 and C-54.
Any help as to what kind of replacement to get...or where?
Thanks in advance. I promise to document to whole process of repair and post for future reference.


--------------------------



 Lunettes De Soleil

[artbylaw]

I can send you some capacitors for the C-49 (I'm not sure if the same type is used for the C-54)
P.M. me your address and I will shoot them over. I got them off eBay and have way more than I need.
- artbylaw

[artbylaw]

Alan......quite a stretch time now with no word as to what is going on with the duplicating process.
I sent you my chip in good faith (even at my expense) in order to try and help you out.
I really hope you do not intend on not replying and just keeping it. That would be wrong in so many ways...
Please get in contact with me.
-artbylaw