boards with 40007 and 40010 slots

Started by WacKEDmaN, 18:15, 17 November 22

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WacKEDmaN

ive been working on a board that has both 40010 and 40007 slots... the 40010 was populated originally but its looking like it maybe bad...
i have some 40007 i tried to run in this board...but there was nothing.. nothing on data lines.. and looked like the 40007 wasnt even powering up...

so i had a look at the slot... it seems this board doesnt have VCC2 required for the 40007..both the VCC2 pins are at ground

from what i read these GAs are interchangable on these boards....
but is there anything else that needs to be done to get VCC2 on pin 9 and 33?

robcfg

Don't mix them!

The pinout is different so they don't get voltage through the same pins! Putting one into the slot of the other will just fry them.

You may need to add a capacitor or a resistor in front of the unused socket in order to use it.

Bur please, double-check it first to avoid ant problem!

WacKEDmaN

#2
oh of course, im not trying to run both at the same time! and i realise they have different pinouts

the capacitor is populated for both slots...

the issue is the 40007 doent have power on both of its VCC2 pins...they are connected to ground instead of 5v (VCC1 is there only)
(look at 664 vs 464 schematic, i should have mentioned this is a MC0002C 464 board)

TotO

And the 40007 require a heatsink.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

WacKEDmaN

not if its not getting power!... doesnt seem to be even warming up in the slightest!
with the 40007 there is zero activity on the data bus...

and ive checked the chip works fine in a 40007 only board

robcfg

That's pretty strange, as both gate arrays get their voltages from the same rails.

To illustrate it, I've done some GIMP magic to show how the traces go to both gate array sockets.

dragon

Check acme servíce  manuals I remember that there is one Schneider with double socket that speak about the two configurations.

https://acpc.me/ACME/

And tell us the motherboard model.

WacKEDmaN

#7
this is what im seeing on the 2 different 464 boards i have here 

original 464 board
You cannot view this attachment.

MC002C board (based on 664...this is from that 664 schematic and is how this board is setup)
You cannot view this attachment.

if i check pin 9 and pin 33 on the 40007 slot there is NO power...its at ground voltage...also the 2 resistors for VCC2 are nowhere to be found!

robcfg

He mentioned that it is a MC0002 board, that's what I've used for my picture.

Point is, if the 40010 has the right voltages, the 40007 must be getting them too.

Corroded or damaged socket, maybe?

WacKEDmaN

ooh wait... i found where R138 and R139 are.... and they are unpopulated!

well that explains why theres no power!... guess they left them out to save pennies (but why populate the capacitor for the 40007 slot!)

WacKEDmaN

#10
guess i need to go grab couple of 1/2W 12ohm resistors today....another 90min walk! LOL

thanks for the help peepz

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