DIY: new cell for NVRAM chip

[Shredder11]

Next time I think I will use an alias on the online form, i.e. J.R. director at Dalltech Just hope I do not get shot as a result...

[Linuxbuilders]

Lately I have found that there were different chips used for falcons over a time. So they differ a bit.
MK48Txxx and MCCS146xxx - the packaging is different so cutting it to get battery out is different exercise.

MK48Txxx - is solid block of plastic, battery is mounted (melted in) on right side of the chip. There is enough to use hot solder iron and melt first 1mm of the top to get to the battery - then solder wires and get external battery connected in place.
MCCS146xxx - is an external shell filled up with silicone, to get to this battery is more messy exercise and more time consuming.

In both scenarios it is worth it because you replace 3V cell without messy external batteries connected through horrible diodes circuits, etc...

New 3V battery is $1 so this 15 minutes of your time is worth it.
In my second falcon I have installed proper battery socket so now I can replace it like PC BIOS battery.

[Shredder11]

I'm wondering if the socket shown here is a low enough profile, to avoid touching the metal shield? No measurements are given so one can only guess using the photo. Otherwise I will have to buy the more expensive one mentioned on the Atari Music Network website.

[simbo]

personaly i just used a standard dil socket {non turned pin}

fits perfect

i think people may use low profile to solder from above
but you can tilt the pcb up a little to solder below easily

there is a very small rise in the top metal {about .5mm}
but this just keeps the nvram in place

if you want to pay extra for this socket fine

done three falcons clocks so far and no issues with a normal dil socket

[wongck]

In both scenarios it is worth it because you replace 3V cell without messy external batteries connected through horrible diodes circuits, etc...

thanks for the criticism.
Well for someone who cannot even solder 2 resistors properly... I think I did pretty well.

[simbo]

i am sure you can solder well
you just need to tin all parts first then solder together
or and use a flux pen or source ...

and for fine parts tweezers

i also dont think the battery idea is good

but its too hard allround
better to snip it off take the pins out
desolder all holes
use a normal dil socket
and solder from below by gently pull the board foward from the metal below
once you ease it out the lower plastic

i think ordering samples in some countrys is harder so also
some people sell the nvram on line for heeps when they get it free
terrible!!!

as with soldering practice makes perfect
good light with a good mag set if needed

? did you get a headset ck??

[Linuxbuilders]

thanks for the criticism.

sorry, it wasn't my intention, I have just tried it and gave up on it. it is not the most perfect solution. best is desolder but after I did one falcon this way I gave up on another one and just "dag out" the dead cell

[mdivancic]

I'm wondering if the socket shown here is a low enough profile, to avoid touching the metal shield? No measurements are given so one can only guess using the photo. Otherwise I will have to buy the more expensive one mentioned on the Atari Music Network website.

That is the socket I used. Worked just fine, no sheild cutting needed.

[Shredder11]

Great I will buy some. Thanks.

[wongck]

sorry, it wasn't my intention, I have just tried it and gave up on it. it is not the most perfect solution. best is desolder but after I did one falcon this way I gave up on another one and just "dag out" the dead cell

The perfect solution would be replacement of the IC itself.
Really seriously.
No mutated tumor diodes and batteries sticking out... looking like Brainiac from the Superman comics.

[wongck]

? did you get a headset ck??

No yet... still.
Any way, I went back to my US Falcon....
Age catching up. The eyes are getting bad. I must have done the nvram solution like 2 or 3 years back when I can see better.
Must be some threshold in years before the eye sight just crash downhill....

[simbo]

I'm wondering if the socket shown here is a low enough profile, to avoid touching the metal shield? No measurements are given so one can only guess using the photo. Otherwise I will have to buy the more expensive one mentioned on the Atari Music Network website.

That is the socket I used. Worked just fine, no sheild cutting needed.

what a total load of rubbish

just use a normal dil socket {any profile picture attached}

there is NO need to cut any sheilding
and NO need of any gold plated turned pin low profile £5 socket

there is also more chance the nvram will just fall out such a socket when the machine gets moved around
in postal or other ways

the socket + nvram measures exactly 15mm height
the ram module with a standard 4mb measures 18mm

ive done now 4 machines just using a dil socket
no cutting cases or other rubbish and no abnormal raising of the metal past maybe .2-.5mm
but holds the chip firm in place as a product of using a sensible normal dil socket

[Dal]

Agree with Simbo - that's exactly what I did on my old Falcon. I did try and hack away at the old chip to see if I could locate the cell and perform a mod using a CR2032, but gave up as I couldn't be arsed with it!

Surely there must be a neater solution with a small board and a different chip with separate pwr source?

[mdivancic]

Whatever simbo. Chill out dude. Worked for me at about $0.50 each. Show some respect once in a while. No poo involved what so ever.

[simbo]

i just dont want the nvram to fall out

turned pins you plug a flat pin dil ic in
the pins are squashed down

they do fall out ..... like very often

normal dil fits the bill
and hug the flat pins this type of ic has its a dil ic
if it was a turned pin ic i see the point



why try to do better than working well and secure
beggers beleve

someone must sell this idea for sure

bit like buffers fitted to european falcons only

same poo ...? dont ask me i just drive the things

[simbo]

http://www.datasheetcatalog.org/datashe ... 12887A.pdf

if you plugged in a nvram and made a mistake with some tools
you can corrupt the nvram 50 bytes etc area with rubbish
or you have or some app has poke'd around it's address
maybe some perif or a bus crash has somehow addresed it

to fix this
take it out the socket or dont!!
and short pin 21{!RCLR}on it to pin 12{GND} or to the screening of the case for the usual 5 second hold period

you must do this with no power applied ie its running on its battery
i assume atari falcons and TT dont address this clear pin
as they have no dry bios.. to do it or physial connections
so if your nvram is STUCK try that
doesnt clear time or timers just nvram block to 1
same goes for most nvram chips with batteries
some use pin 22

so senarios like ohmf my 600 quid machine [smilie=greencolorz4_pdt_05.gif] poo i woke up this morning

and my machine no longer boots no video i am going to cry
my TT/falcon has bad wait states and strange disk errors
can be fixed by shorting these two pins with no power
then replace the nvram as the cell is prob dead or less than needed for a storage
or the corruption of settings is very bad and the battery and nvram chip is prob aok!!!

maybe a cell group nibble setting range is 0 -4 and some other address is there like F or B
setting an out of range mode the register in say videl doesnt see...valid

if you do this pin RCLR to pin GND then power on
the machine will revert to u.s.a and normal vga etc...

till you replace the clock chip or its battery{better cure}

now stop moaning and try this first!

BUT

senario exists where the battery runs out
but the nvram doesnt clear to zero {ie 1 } as you expect when a battery fails
total rubbish it never will cells {bits} will remain at 1 even with NO battery connected
till you clear it or write all 1 to nvram area

a 1 state takes non loaded cells on these nvram
and cells can have stuck charges of electrons not able to then release...
setting bit data perminant to them even if the battery fails totaly

so can stick a machine till you short the pins or pull and replace the nvram
following its reboot precedure
some nvram dont have this pin !RCLR most older ones will
forinstance DS12887A has this pin 21 so can easily be cleared to 1

so look to google for the nvram you have and find if this pin is there !RCLR

[simbo]

so some falcons
you need to lift pin24 off
and power it alone with a battery some people like wongck have done this mod
but had issues and this is why

and with the falcon power off
short 21 to 12
as the chip is with a flat battery it wont have the power to clear its self !!

so elfacto incluso

if you do the battery mod to a falcon
you should short pins 21 and 12 with the battery connected
before you power on

to avoid issues with video etc nvram data... thats maybe still corrupt till you clear it

i hope this clears up the nvram issues

and the same applies to mega machines with cells and TT machines with cells
replace the cell
short the RCLR to GND usualy 21 or 22 to 12 for 5 seconds

then power on as normal and set the nvram as needed for your monitor etc etc. time

[wongck]

when I first did the mod, I was powering it with a 3.6V lit battery instead of the AA batteries.
With the V drop across those few diodes in my mod, I guess there was not enough juice to clear itself or whatever reason.
It was not working until later I put in the AA batteries as I saw it on my TT.
(was a situation of nothing to loose if I try it.... )

[simbo]

nice ck

what i am meaning is

1} if you replace or add a new cell on any NVRAM
you must clear it's ram to 1 with no power to machine {ie the nvram chips vcc pin}
but with battery connected
this forces all nvram bytes to 1 but it will only do this when there is power like battery
a 'dead' battery nvram cant flash its self to 1

2} if you change an nvram you should make sure its clear if it has a RCLR pin by shorting it to pin 12 or its ground pin{gnd}
before fitting
if it has no pin 21 22 RCLR etc

i would NOT use it !!!
i previously got a DS12887A+ it has no RCLR pin ie 21 or 22 where the DS12887A has pin 21 !RCLR
and you can dig the battery from the top maybe add a crystal also if needed
when done
falcons will revert to u.s.a standard vga
and TT mega and falcon previous run diag data will be cleared
this includes fault trace data the nvram stores and vga etc settings

above all nvram can be corrupted in ways not detectable but implicative on runtime events
till cleared on power off state but with a good battery on the nvram
using the rclr pin {look to the datasheet}

[simbo]

where this leaves your mod ck to the vcc pin 24 is 'unclear' if you excuse the pun

other than it prob cant be cleared
and runs all the time from the battery cell's

its therefore quite probable the only people who have a proper init set nvram
are people who replaced the chip

people who just changed a battery and didnt short the pins
{tt mega etc owners prob also machines like hades etc}
prob have odd ram cells still set

not sure the nvram tools clean the nvram first then reprogram it on exit
then demand a power off / on cold restart and it will reinit from fresh,..

therefore if i had a failed clock ..machine or the likes of a TT mega or hades etc

i would use such a tool to clear the nvram to 1
by writing zero to its 50 or more bytes

then power down and replace the cell then short RCLR pin to gnd just to be sure

this way youll have fresh init settings
factory reset
i will ask mr.hddriver for the source of his nvram tool

you never know...

TTowner and others take note... maybe hades issues are caused by something like this

[Solarricht]

Im a proud new falcon 030 owner and new to all this. I read this thread before attempting anything. The machine i bought was totally origional. Alas the old connor drive packed up which made the floopy drive disfunctional. Thought it was linked to NVram battery prob. Braved it and lifted off the lid...
Took me a while to locate the chip in question using photos from here. Was aware id probably ditch the chip & source a new one so didnt have much to loose by attacking the plastic case on this chip. I levered the top off (was lucky not to damage the crystle. But the top came off soon enough in several peices. Could see the hidden battery glued using black silicon. Noted polarity & measured battery voltage: 0.08volts, and removed battery contacts. Soldered two wires to the pins where the contacts were placed. I now have a cr2032 battery & holder on the other end of the wires. The chip looks messy as its impossible to remove all the silicon as theres thin wires holding the crystal. But it works lovely, and can replace the battery when ever i like. I honestly think this mod is easier than desoldering the motherboard & sourcing hard to find chips. I have also now put in a CF card & adapter in too. Disconnected the fan and now have a lovely silent falcon running good as new! Got an scsi cable today and transfered all my ST software from a scsi card reader i was using with the ST. I love a successful project! Time to make music...

[Shredder11]

Very well done and dare I say it, welcome to the elite Falcon 030 club!

[smilie=greencolorz4_pdt_01.gif]

[wongck]

Was aware id probably ditch the chip & source a new one so didnt have much to loose by attacking the plastic case on this chip. I levered the top off (was lucky not to damage the crystle. But the top came off soon enough in several peices. Could see the hidden battery glued using black silicon. Noted polarity & measured battery voltage: 0.08volts, and removed battery contacts. Soldered two wires to the pins where the contacts were placed. I now have a cr2032 battery & holder on the other end of the wires. The chip looks messy as its impossible to remove all the silicon as theres thin wires holding the crystal. But it works lovely, and can replace the battery when ever i like. I honestly think this mod is easier than desoldering the motherboard & sourcing hard to find chips.

Yap, that's another way to skin the cat
Get some photos of the mod. Would love to have a look at it.

[Fox-1]

(side note: isn't there a regular "hardware" section for Falcon? This one is named "professional" so I don't really belong here )

Don't want to hijack the topic but this is what I did this evening...

I have a Falcon laying around for a long time. Just the computer, no HD or whatever. I was in need for a test 1440KB floppy drive for my MegaSte and opened up the Falcon to rip the FDD. The drive didn't work on the MegaSTe and I needed to focus on something else because that MegaSTe is driving me nuts right now.

So, with the Falcon on the table I decided to finally connect the thing to see if it actually works. Well, it did, but the clock was reset so probably a dead battery. Some years ago I read about hacking a Dallas RTC from a classic IBM system and since the MK48T87B-24 has a similar set-up I decided to try to open it. I'm sure I'm not the only one who tried that.

Sooo, time to replace a battery the hard way.

This is what I started with. Notice the small scratch I did just before I realized it may be fun to take some pics of it.



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What is the location of the battery? Could be left or right and I choose to start at the left side.



Of course, with a 50% chance you always need to have the other half and this case was no different. It didn't take long until I hit something that was definitely not a battery.

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Time to switch to the right side.



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And there it is.



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Removing some more epoxy and soldering a firm wire to the battery to see if I can lift it that way.



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Lifting it this way seemed to work pretty well.



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Now the battery is removed I know that none of the connections go to the left side so it's reasonably safe to cut away what I don't need. Don't put away the old battery yet. In case you forget the polarity you can take a peek at it later on



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I discovered I didn't have any battery clip holder laying around so time to sacrifice an Intel board for a better cause. Also cut a small piece of plastic from a CDR which will be power-glued to the battery clip.



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Connecting some wires.



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Add some hot-glue to secure both the wires and the remaining piece of epoxy in where the crystal is located.



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Mounting the battery with a screw from the power supply and use a black marker to paint the glue.



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Testing with XControl. Mission accomplished. After a power-down/-up the clock keeps running as it should. Don't mention the date on the screen. It's the same one as I typed before the power-down

[DarkLord]

Good job. Always gratifying to do something yourself and have it come out right.