Replacing the AT25256 EEPROM on a BasicX-24 Module.

Started by Robotics_Job_Search March 18, 2005

Does anyone have experience replacing the surface mount AT25256 EEPROM
on a BasicX-24 Module?

Mine is bad (NetMedia refuses to replace the BasicX Module) and I'm
deciding between replacing the EEPROM, or buying a Systronics JStamp (the
JStamp is more expensive, but substantially more powerful
http://www.systronix.com/jstamp/)

I don't have any experience with surface mount soldering, but I
suppose I could do it if I had the proper tools (I have a regular 30W
pencil iron and a Weller 150/230W gun, but both are way too big for surface
mount work.) I'd appreciate any advice. Thank you. Good Luck!
Ken_S.

At 07:46 PM 3/9/2005, you wrote: >Don;
>
> >When I run your program on a current production BX-24, the read and
> >written values are the same (as expected).
>
> Thanks! Then only conclusion I can come to is that my BasicX-24 is
>bad. Anyone else agree/disagree?
>
> I had sent it back once already because I had trouble getting it to
>take downloads. Often I have to try three to five times (sometimes more)
>before it will verify okay. One night I tried for over an hour and it
>never took it. I discussed it with NetMedia Support (I explained the
>signals I saw on my O-Scope for pins 1, 2, and 3 of the BasicX Module, and
>the signals on pins 1, 2, 5, and 6 of the EEPROM chip) and they agreed to
>replace it. However, they sent it back saying they tested it and there was
>no problem with it. It continues to take multiple downloads to verify
>okay, and data saved to the unusued area of the EEPROM (data-logging) comes
>back as garbage.
>
> Any advice on working with NetMedia a second time? > Thank you.
> Ken_S.
>
>At 04:33 PM 3/9/2005, you wrote:
>
> >When I run your program on a current production BX-24, the read and
> >written values are the same (as expected).
> >
> >Don >At 08:28 PM 3/8/2005, you wrote: > > I'm having a problem writing/reading to/from the EEPROM. I've come to
> >the conclusion that either...
> >
> > 1) My BasicX-24 has gone kaput.
> > or
> > 2) I am missing something very simple.
> >
> > Would someone mind running this program and tell me what they get for
> >an output? Seems to me that what I write to the EEPROM should exactly
> >match what I read back.
> >
> >'************************************************************************
> ******
> >Option Explicit
> >Option Strict On
> >
> >Private Const ciELEMENT_SIZE As Integer = 2 '*** Integers take two Bytes ***
> >Private Const clHIGHEST_EEPROM_ADDRESS As Long = 32765
> >Private Const clLOWEST_EEPROM_ADDRESS As Long = 32700
> >Private lAddress As Long
> >
> >Public Sub Main()
> > Dim iX As Integer
> > Dim iX2 As Integer
> >
> > Debug.Print "Begin"
> > lAddress = clLOWEST_EEPROM_ADDRESS
> > Do While ( lAddress < clHIGHEST_EEPROM_ADDRESS )
> > Debug.Print "Address="; CStr(lAddress); ", ";
> > iX = CInt(Rnd() * 65536.0 - 32767.0)
> > Call PutEEPROM(lAddress, iX, ciELEMENT_SIZE)
> > Debug.Print "iX="; CStr(iX); ", ";
> > iX2 = 0
> > Call GetEEPROM(lAddress, iX2, ciELEMENT_SIZE)
> > Debug.Print "X2="; CStr(iX2)
> > lAddress = lAddress + CLng(ciELEMENT_SIZE)
> > Loop
> > Debug.Print "End"
> >End Sub
> >'************************************************************************
> ******
> >
> > I'm getting data like this...
> >'************************************************************************
> ******
> >Begin
> >Address2700, iX=-29521, X21919
> >Address2702, iX563, X2563
> >Address2704, iX&323, X2=-20269
> >Address2706, iX 595, X2$947
> >Address2708, iX 272, X2=-21200
> >Address2710, iX=-20477, X2=-30973
> >Address2712, iX506, X2=-23686
> >Address2714, iX=-18517, X2'563
> >Address2716, iX=-684, X2=-684
> >Address2718, iX044, X2=-18260
> >Address2720, iX%988, X2=-28540
> >Address2722, iX=-30543, X2=-5711
> >Address2724, iX=-6199, X2=-26167
> >Address2726, iX4, X22
> >Address2728, iX333, X2501
> >Address2730, iX!74, X2I90
> >Address2732, iX"580, X2=-22220
> >Address2734, iX2268, X2(172
> >Address2736, iX=-1541, X2=-11269
> >Address2738, iX=-24806, X2874
> >Address2740, iX772, X22484
> >Address2742, iX609, X2609
> >Address2744, iX=-27513, X2239
> >Address2746, iX=-10857, X2=-30057
> >Address2748, iX2301, X2"317
> >Address2750, iX=-31563, X2821
> >Address2752, iX%130, X2=-10710
> >Address2754, iX2065, X2=-3775
> >Address2756, iX=-10435, X2=-23747
> >Address2758, iX=-26539, X2=-11179
> >Address2760, iX=-27313, X2=-27313
> >Address2762, iX774, X2=-2354
> >Address2764, iXy21, X2=-15
> >End
> >'************************************************************************
> ******
> >
> > Shouldn't iX be equal to iX2? As you can see from the above data they
> >do NOT match. Please tell me if my BasicX is bad, or what I'm doing wrong
> >in my program.
> >
> > Thank you.
> > Ken_S.





--- In , Robotics_Job_Search
<Robotics_Job_Search@C...> wrote:
> Does anyone have experience replacing the surface mount AT25256
> EEPROM on a BasicX-24 Module?

My (admittedly limited) experience with SMT is that re-work is
decidedly more difficult and problematic than new work. I might
suggest that instead of trying to replace it, just lift pin 1 and
then connect a new EEPROM in using the 7 holes that run between pin 1
and pin 24.

If you do decide to replace the EEPROM, go get a good quality 15W or
less soldering iron with a very thin tip. It might work best to clip
each of the 8 leads to remove the package, heat and remove each of
the clipped leads separately and then soak up as much of the solder
as you can with solder wick. You can also remove SMT devices with a
hot air gun (like that used to strip paint) but the problem is that
you may remove more devices that you intended to. There are
specially made hot air guns for SMT rework but they are fairly
expensive.

When you place the new device you'll want to align it carefully and
then press it down with tweezers while you touch the soldering iron
briefly to leads on each of two opposite corners. After confirming
that the alignment is good you can proceed to touch each of the
remaining 6 leads with the iron. You'll find that it doesn't take
much heat and it might not require any more solder at all. You'll
just have to see.

If you know anyone that does SMT work, see if you can get them to do
it or see if you can borrow some solder paste. That makes it much
easier.

Don



Re: Replacing the AT25256 EEPROM on a BasicX-24 Module.
I would agree with Dons comments. Buy yourself a good headset
magnifier.( like jewellers use). Clip the leads of the dead device and
lift away the component body, then carefully unsolder & remove each pin
one at a time. Trying to unsweat the whole device is frought with
disaater IMHO
Have a practice first on a dead TV remote or something similar. Practice
makes perfect.
neil

Don Kinzer wrote:

>
> --- In , Robotics_Job_Search
> <Robotics_Job_Search@C...> wrote:
> > Does anyone have experience replacing the surface mount AT25256
> > EEPROM on a BasicX-24 Module?
>
> My (admittedly limited) experience with SMT is that re-work is
> decidedly more difficult and problematic than new work. I might
> suggest that instead of trying to replace it, just lift pin 1 and
> then connect a new EEPROM in using the 7 holes that run between pin 1
> and pin 24.
>
> If you do decide to replace the EEPROM, go get a good quality 15W or
> less soldering iron with a very thin tip. It might work best to clip
> each of the 8 leads to remove the package, heat and remove each of
> the clipped leads separately and then soak up as much of the solder
> as you can with solder wick. You can also remove SMT devices with a
> hot air gun (like that used to strip paint) but the problem is that
> you may remove more devices that you intended to. There are
> specially made hot air guns for SMT rework but they are fairly
> expensive.
>
> When you place the new device you'll want to align it carefully and
> then press it down with tweezers while you touch the soldering iron
> briefly to leads on each of two opposite corners. After confirming
> that the alignment is good you can proceed to touch each of the
> remaining 6 leads with the iron. You'll find that it doesn't take
> much heat and it might not require any more solder at all. You'll
> just have to see.
>
> If you know anyone that does SMT work, see if you can get them to do
> it or see if you can borrow some solder paste. That makes it much
> easier.
>
> Don > *
> click here
> <http://www.netflix.com/Default?mqso`190075" target="_blank" rel="nofollow">http://us.ard.yahoo.com/SIG93ma673/M)8184.6191685.7192823.3001176/D=groups/S06554205:HM/EXP11203311/A%93423/R=0/SIGel9gslf/*http://www.netflix.com/Default?mqso`190075 >
>
> *>.





Don;

>just lift pin 1 and then connect a new EEPROM in using the 7 holes
>that run between pin 1 and pin 24.

Wow! I just looked at the BasicX-24 schematic; soldering to J1 is
brilliant!!! I could even use the DIP version of the AT25256, which I do
have experience working with DIP size components. Thanks for that GREAT
advice!!! >Before you buy a JStamp, send me an email and we can discuss
>some options.

What "options" do you have in mind? Good Luck!
Ken_S.

At 10:35 PM 3/17/2005, you wrote: >--- In , Robotics_Job_Search
><Robotics_Job_Search@C...> wrote:
> > Does anyone have experience replacing the surface mount AT25256
> > EEPROM on a BasicX-24 Module?
>
>My (admittedly limited) experience with SMT is that re-work is
>decidedly more difficult and problematic than new work. I might
>suggest that instead of trying to replace it, just lift pin 1 and
>then connect a new EEPROM in using the 7 holes that run between pin 1
>and pin 24.
>
>If you do decide to replace the EEPROM, go get a good quality 15W or
>less soldering iron with a very thin tip. It might work best to clip
>each of the 8 leads to remove the package, heat and remove each of
>the clipped leads separately and then soak up as much of the solder
>as you can with solder wick. You can also remove SMT devices with a
>hot air gun (like that used to strip paint) but the problem is that
>you may remove more devices that you intended to. There are
>specially made hot air guns for SMT rework but they are fairly
>expensive.
>
>When you place the new device you'll want to align it carefully and
>then press it down with tweezers while you touch the soldering iron
>briefly to leads on each of two opposite corners. After confirming
>that the alignment is good you can proceed to touch each of the
>remaining 6 leads with the iron. You'll find that it doesn't take
>much heat and it might not require any more solder at all. You'll
>just have to see.
>
>If you know anyone that does SMT work, see if you can get them to do
>it or see if you can borrow some solder paste. That makes it much
>easier.
>
>Don >
>
>Yahoo! Groups Links >
>





Since I may be changing the EEPROM anyway, does anyone know if I could
use a AT25HP512 (64Kx8) in place of the AT25256 (32Kx8)? That would double
the Memory for programs, and Data-Logging (I'm using Data-Logging in my
current project.) Thank you. Good Luck!
Ken_S.

At 11:00 PM 3/17/2005, you wrote: >Don;
>
> >just lift pin 1 and then connect a new EEPROM in using the 7 holes
> >that run between pin 1 and pin 24.
>
> Wow! I just looked at the BasicX-24 schematic; soldering to J1 is
>brilliant!!! I could even use the DIP version of the AT25256, which I do
>have experience working with DIP size components. Thanks for that GREAT
>advice!!! > >Before you buy a JStamp, send me an email and we can discuss
> >some options.
>
> What "options" do you have in mind? > Good Luck!
> Ken_S.
>
>At 10:35 PM 3/17/2005, you wrote: > >--- In , Robotics_Job_Search
> ><Robotics_Job_Search@C...> wrote:
> > > Does anyone have experience replacing the surface mount AT25256
> > > EEPROM on a BasicX-24 Module?
> >
> >My (admittedly limited) experience with SMT is that re-work is
> >decidedly more difficult and problematic than new work. I might
> >suggest that instead of trying to replace it, just lift pin 1 and
> >then connect a new EEPROM in using the 7 holes that run between pin 1
> >and pin 24.
> >
> >If you do decide to replace the EEPROM, go get a good quality 15W or
> >less soldering iron with a very thin tip. It might work best to clip
> >each of the 8 leads to remove the package, heat and remove each of
> >the clipped leads separately and then soak up as much of the solder
> >as you can with solder wick. You can also remove SMT devices with a
> >hot air gun (like that used to strip paint) but the problem is that
> >you may remove more devices that you intended to. There are
> >specially made hot air guns for SMT rework but they are fairly
> >expensive.
> >
> >When you place the new device you'll want to align it carefully and
> >then press it down with tweezers while you touch the soldering iron
> >briefly to leads on each of two opposite corners. After confirming
> >that the alignment is good you can proceed to touch each of the
> >remaining 6 leads with the iron. You'll find that it doesn't take
> >much heat and it might not require any more solder at all. You'll
> >just have to see.
> >
> >If you know anyone that does SMT work, see if you can get them to do
> >it or see if you can borrow some solder paste. That makes it much
> >easier.
> >
> >Don
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>Yahoo! Groups Links >
>





Re: Replacing the AT25256 EEPROM on a BasicX-24 Module.
> ... a AT25HP512 (64Kx8) in place of the AT25256 (32Kx8)?

See http://groups.yahoo.com/group/basicx/message/17968, two weeks ago. Tom
Tom Becker
--... ...--
www.RighTime.com
The RighTime Clock Company, Inc., Cape Coral, Florida USA
+1239 540 5700



Oops! You caught me; I should'a searched past messages first! (Sorry.)

At 03:07 PM 3/19/2005, you wrote:

> > ... a AT25HP512 (64Kx8) in place of the AT25256 (32Kx8)?
>
>See http://groups.yahoo.com/group/basicx/message/17968, two weeks ago. >Tom >
>Tom Becker
>--... ...--
> www.RighTime.com
>The RighTime Clock Company, Inc., Cape Coral, Florida USA
>+1239 540 5700 >
>
>Yahoo! Groups Links >
>