DIY: new cell for NVRAM chip

[wongck]

Great job, I am impressed.

Isn't there a battery small enough to squeeze into the hole on photo #6 (lifting the battery out) ?
Couldn't make it out but was it possible to connect up the wires at the battery rather than sawing & going further down?
Was there a photo just before you connect the blue & red wires to the chip?
I wonder how that looked.

[Fox-1]

Great job, I am impressed.

Isn't there a battery small enough to squeeze into the hole on photo #6 (lifting the battery out) ?

Yes, there is. Just take the same type as that was originally in there and it will fit if you solder it directly to the tiny pins on the IC. Not an easy task but doable. I even have such a battery but didn't want to use it. It's pain in the a** the replace it next time (in about 10 years or so )

My goal was to use a CR2032 cell as these are also used on my Atari 8-bit RTC's and it's a very common type as it's about the most used one on PC boards. It's also bigger than the original so lasts longer.

Couldn't make it out but was it possible to connect up the wires at the battery rather than sawing & going further down?

You can't place a new one without disconnecting the old one and since the battery connections are welded (not soldered) to the IC pins you'll have to cut at least one connection. The one on top will be hard to cut as it's wide and there is no space to fit a wire cutter or something like that. The one on the bottom can't be reached without lifting the battery so if it has to be lifted anyways it's easier to just remove it.

Was there a photo just before you connect the blue & red wires to the chip?

There was one but it was too much out of focus so not usable. Maybe the one below will do. The pins coming out of the IC are really small. The left one (negative) is a bit bigger because it has a piece of the connection lid from the old battery attached to it.

[wongck]

Using a CR2032 is a good idea as those are readily available almost everywhere.

You can't place a new one without disconnecting the old one and since the battery connections are welded (not soldered) to the IC pins you'll have to cut at least one connection. The one on top will be hard to cut as it's wide and there is no space to fit a wire cutter or something like that. The one on the bottom can't be reached without lifting the battery so if it has to be lifted anyways it's easier to just remove it.

What I was think of was pop a small battery replacement, so you need to remove it first. From your description it's not a battery holder of some sort but directly welded.
I was just thinking was it possible to connect a new battery without too much mold compound removal.

There was one but it was too much out of focus so not usable. Maybe the one below will do. The pins coming out of the IC are really small. The left one (negative) is a bit bigger because it has a piece of the connection lid from the old battery attached to it.

That's looks too small for me. May be someone with much soldering experience can attempt it.

Great stuff !!! Glad it worked very well for you.

[DarkLord]

That's looks too small for me. May be someone with much soldering experience can attempt it.

Don't feel bad - it was too small for my tired old eyes as well. That's why I had Alex Yu at ATY
Computers do it for me. He replaced the entire chip so its socketed. Any time it dies now, I
can just pop a new chip in myself.

[Fox-1]

He replaced the entire chip so its socketed.

I have too much stuff laying around so everything that has to be fixed I do with the parts I have, one way or another

[DarkLord]

He replaced the entire chip so its socketed.

I have too much stuff laying around so everything that has to be fixed I do with the parts I have, one way or another

Nothing wrong with that!

PS Love that sig....

[Fox-1]

PS Love that sig....

A few weeks ago, when the BBS went bye bye, I didn't like it that much

[DarkLord]

PS Love that sig....

A few weeks ago, when the BBS went bye bye, I didn't like it that much

Ouch, sorry. I was taking it as a play on words, not a final epitaph.

[Noelio]

Hi guys,

I, too, have the famous dead NVRAM issue (*I hope* but it's worth getting this done first if it's not).
I've sourced DS12887A chips from Maxim but for the life of me I couldn't find the sockets there.

I did find the one below from Jameco. Could you guys tell me if this socket is good enough?

https://www.jameco.com/webapp/wcs/store ... _652359_-1

[Dal]

Yup, that's the one.

[Noelio]

Excellent. I ordered 2 sockets and two standard 12887's. Now to wait!

[Noelio]

Hrrrm I guess it's not the NVRAM. Too bad as I think I did a pretty good job socketing Dallas.

Thinking any one of U62,63,67,68, 44 may be burned out but not sure and I'm really not skilled with a logic probe. It's probably time to send this bird to the sanctuary unless I could find some cheapo gals.

[Dal]

See if Rodolphe Czuba will look at it for you. He's probably the only person I know who has a solid knowledge of the Falcon hardware.

[Guest]

make sure when testing falcon hardware pcb
you have the base metal on it and the foil strip on the rear

if you dont ground all sockets

the falcon will never boot
if you add a test cart its like a mad screen full or badly knitted out of scraps of red and blue and green wool
but rs232 to a pc reports aok... for tests using hyperterminal

you can ground the rs232 port only on the rear and it will work

its due to the rs232 interrupt . and the mfp
documented in other topics by me and others

[JustinPayne]

make sure when testing falcon hardware pcb
you have the base metal on it and the foil strip on the rear

if you dont ground all sockets

the falcon will never boot
if you add a test cart its like a mad screen full or badly knitted out of scraps of red and blue and green wool
but rs232 to a pc reports aok... for tests using hyperterminal

you can ground the rs232 port only on the rear and it will work

its due to the rs232 interrupt . and the mfp
documented in other topics by me and others

Hey Simbo,

I really liked your work on the motherboard by socketing the IC. Very clean and professional looking. I need to do the same myself and I think I found the parts I need but I just want to make sure and I was wondering if you could confirm this. Parts are...

http://www.digikey.com/product-detail/e ... 0817933264

and...

http://www.digikey.com/product-detail/e ... ND/3313537

I confirmed as much as I could with what I know. I figured you could get me the rest of the way.

Thanks,
Michael

[Guest]

the parts your looking at are fine to use

work slowly use a 18watt or 15 watt iron
you may need to use a 25watt iron on some pins that are ground
as the ground spreads the heat away too fast for a 15 etc
and ask for help from a pal to cut off the old chip using small sharp cutters
take the pins out step 1 clean the holes of old solder
step 2 and step 3 re-solder the socket

[qq1975b]

Hi,

Maybe a silly question with a short answer....Replacing the NVRAM is a little painful...putting it on a socket or replacing the inner battery. All for these features?

Holds time and date
Holds keyboard language setup
Holds desktop language setup
Holds SCSI ID init setup
Holds Video boot setup

About this last feature (video). It is just on boot screen? Atari logo and memory test? because the saved desktop configurations saves the resolution and colours on screen, right? What info is stored on the NVRAM about VIDEO? What is it used for?

thanks

[Guest]

if you alter the nvram or reset it there is also some register settings for dma interactions etc
some info on previous powerons
some chips dont have a reset pin {mclr}
you can end up with a dead machine till its replaced

doing the battery and if needed the crystal mod is quite easy

adding a small recharging circuit {3 components} will allow you to recharge the cell {nicad or lithium}
so it cant go wrong again or even also add a 5v solar cell and one more diode to the lid of your machine ...

so.. you can mod the ic and there is no need for solders ...
ill try to hunt out all the topics about this in the section
and add a set of links to the main bits

i have a falcon here for repair
so ill do the mod as its a DALLAS 1287 thats in it
the potted box type
so out with the dremil
the trick is to use a cloth and make a hole thru it for the chip
then tape it to the board so you can keep the little bits off the pcb and chip pins
bit like a surgeon using a mini drill and a BURR tip is prob best

[Guest]

here is some images links to info about the DS1287 {potted type chip}
there are a few versions of ic used in falcons if you want detail on others then use google images link





a french forum with some nice pics method and how to reseal etc
http://forum.system-cfg.com/viewtopic.p ... lit=dallas

used a bur bit and took me 5 mins to drill and connect and epoxy
dont forget to sever the battery from its negative lower pin i just used the burr and got a nice clean cut

[qq1975b]

Don't you take out the old battery from the chip?

[Guest]

if its one of the potted
in a box type like this one in the falcon DS1287 not A or A+ etc
then when you drill with a burr or other down you remove the connection to negative of the cell
best not to remove the cell its in a tomb and will quietly go to sleep and turn prob to a crystal less waist to get in your lungs
look at the french link better pics than i uploaded

anyway the falcon works now i did today keeps time perfectly now
gals in wrong sockets bad connections on the mpu
poor clock patch removed for now ill prob redo it
think he got it broken from some place

[Guest]

http://www.ebay.co.uk/itm/250893085405? ... 1497.l2649
$10
prep it and pre fit a cell
ignore the inbuilt one
this is a fresh flash ic
so well its ok for $10 delivered
i got 1 for stock ill mod
i want to fit it to my falcon i put a A+ but im not happy...
as i said ive used A and A+ better to stick too what i know works
fresh ic and by pass the old bat
so...

[dhedberg]

anyway the falcon works now i did today keeps time perfectly now
gals in wrong sockets bad connections on the mpu
poor clock patch removed for now ill prob redo it
think he got it broken from some place

Great work! Every Falcon saved counts!

[Guest]

i got 5 1287 from china and checked the cell voltage from a bur down
it was 3.0 - .1v
so if you replace the nvram or change it for a 1287
make sure of the cell volts
so i have 5 ive modded five to add just wires
add a 3v cell rechargable and a solar cell on the top of the falcon with a plug socket so its easy to take off
never run out of time again
you get these 3.3 v - 5v cells solar elements {flashed glass very good if kept dry} from the car things you plug in your garden to charge tokens buy from fuel
then people leave them on so they never charge up!!! so turn them off to charge then once a month you can light your garden all night
the contacts and cells root so take them indoors and do some surgery to charge up your falcon cell
one diodes
cell 4.5v ---- diode >|--- +++++=== +
---------------------------------------= -
-----------------------------------------

http://www.ebay.co.uk/itm/2-x-MAXELL-ML ... 23359f5b4e
you just need a 3.9 v zener diode and a small value like 150R resistor
to clamp the battery not above 3.9 this is .6v higher and is fine
so
solar cell + diode --->|----- + 5v-.6 = 4.4 + 22R
-
-~> + 3.9v
so the clamp zener goes across the cell
well if you were to charge one of these cells fully
it would last around 3 - 5 years anyway
with any light
so you can safely
bury your nuclear falcon now and dont look back
as long as you have a light buld for i think four hours a month
nu bunker

[1st1]