VOGONS


First post, by DAVE86

User metadata
Rank Member
Rank
Member

So I was testing some old Athlon cpu's I got from a flea market. The Post analyzer likely fed voltage back to some data bus. I wasn't sure what went wrong so naturally I wipped out another nforce2 S462 board plugged in the post card and then again toasted the southbridge. The CPU's are ok so I guess the northbridges are too.
I have a hot air and IR stations but no stencils for such chips. They don't seem too difficult to reball by hand if needed. I'm going to source some nforce2 MCP's and swap out the chipsets.
If anyone experienced similar I'd appreciate the feedback about my chances reviving the two boards. Anyway I'll post updates here as it might entertain someone.

Have a Nice Day!

Reply 1 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

So apparently chip revision somewhat matters depending on the board. Going through my parts box I've found a nforce2 socket A board that probably died of natural causes. The south bridge simply fried itself over time. Though this motherboard turns on the south bridge gets to about 50C in a second and it's in constant reset. Never mind since it uses revision 'A' and I need revision 'S' south bridge. Tomorrow I'll have time to take off the bad chip. Might make some pictures along the process.

Reply 2 of 19, by Tetrium

User metadata
Rank l33t++
Rank
l33t++

Is your POST diagnostics card new or did you have it for a while before it went faulty?

Whats missing in your collections?
My retro rigs (old topic)
Interesting Vogons threads (links to Vogonswiki)
Report spammers here!

Reply 3 of 19, by DAVE86

User metadata
Rank Member
Rank
Member
Tetrium wrote on 2023-05-31, 10:29:

Is your POST diagnostics card new or did you have it for a while before it went faulty?

It's from Ebay. Single chip (CH311L) 2015. PCI/ISA type. I have a bunch of different ones. After the accidents I tried it in a crappy P3 board and it couldn't post with the diag card. Shut it off immediately. Never going to use this one ever again.

Reply 4 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

Decided to remove the bad chips while I try to source replacements. I used an aging setup consisting of a ceramic preheather and a hot air rework station. I used this ghetto setup before on larger things and there were never any issues.

First I practiced on a beaten up Gigabyte GA-7n400. Figured out the temperatures and stuff and the chip came off nicely. PCB is fine.

DSCF8958.jpg
Filename
DSCF8958.jpg
File size
904.46 KiB
Views
1998 views
File license
Public domain

The next was one of the boards that got killed by that diag card. MSI K7N2. Also no issues. Clenaed the pads on the board. Looks good.

DSCF8959.jpg
Filename
DSCF8959.jpg
File size
708.35 KiB
Views
1998 views
File license
Public domain

Nforce2 MCP rev A and S removed

DSCF8960.jpg
Filename
DSCF8960.jpg
File size
456.5 KiB
Views
1998 views
File license
Public domain
DSCF8961.jpg
Filename
DSCF8961.jpg
File size
439.55 KiB
Views
1998 views
File license
Public domain

And last the other victim, Gigabyte GA-7n400 Pro2. This has the most features.

DSCF8962.jpg
Filename
DSCF8962.jpg
File size
732.06 KiB
Views
1998 views
File license
Public domain

This time it went not so well. Like before the chip came off the board... and took some pads with it. Must be something with the solder expanding, some stress or I don't know. I was dissapointed. Though it seem that these pads don't connect any circuit traces it is still worrying.

Also the resist mask got damaged on the board a bit so I have to fix it up before the rework.

Last edited by DAVE86 on 2023-05-31, 12:06. Edited 1 time in total.

Reply 5 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

This is how the damage looks on the board and the chip:

DSCF8964.jpg
Filename
DSCF8964.jpg
File size
413.48 KiB
Views
1997 views
File license
Public domain
DSCF8965.jpg
Filename
DSCF8965.jpg
File size
451.27 KiB
Views
1997 views
File license
Public domain

Reply 6 of 19, by janih

User metadata
Rank Member
Rank
Member
DAVE86 wrote on 2023-05-31, 11:42:
Tetrium wrote on 2023-05-31, 10:29:

Is your POST diagnostics card new or did you have it for a while before it went faulty?

It's from Ebay. Single chip (CH311L) 2015. PCI/ISA type. I have a bunch of different ones. After the accidents I tried it in a crappy P3 board and it couldn't post with the diag card. Shut it off immediately. Never going to use this one ever again.

Was the card like this? I hope it is not common that this diag cards cause such damage.

Attachments

Reply 7 of 19, by weedeewee

User metadata
Rank l33t
Rank
l33t
janih wrote on 2023-05-31, 17:53:
DAVE86 wrote on 2023-05-31, 11:42:
Tetrium wrote on 2023-05-31, 10:29:

Is your POST diagnostics card new or did you have it for a while before it went faulty?

It's from Ebay. Single chip (CH311L) 2015. PCI/ISA type. I have a bunch of different ones. After the accidents I tried it in a crappy P3 board and it couldn't post with the diag card. Shut it off immediately. Never going to use this one ever again.

Was the card like this? I hope it is not common that this diag cards cause such damage.

If you have that card, and if that is OP's card, then have I got bad news for you.
The ISA part isn't connected underneath the chip, the traces run there and then just end. Also the ISA connector isn't quite right and could potentially short adjacent pins.
The pci part worked for me, although it does get detected as a PCI device as well.
I know I have some photos of the card somewhere with the chip removed, I'll add /link them when I find them .

file.php?id=127929

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 8 of 19, by Deunan

User metadata
Rank Oldbie
Rank
Oldbie

On more than one occasion I've put the POST card into ISA slot the wrong way around. PSU would trip right away, but there doesn't seem to be any mobo damage. Wasn't such a "modern" PCI mobo though. Also, different POST card.

As for the lifted pads, could be weak glue on the PCB. I don't deal with BGA often (in fact I try to stay away from such packages, not enough experience with those and no access to Xray machine to inspect the soldering job afterwards) but I've seen pads that come off the PCB with temperatures that were not excessive. Could be too long heating or not enough thermal soak from the bottom preheater but frankly there is always some risk with PCBs that have seen a lot of thermal cycles.

Reply 9 of 19, by DAVE86

User metadata
Rank Member
Rank
Member
janih wrote on 2023-05-31, 17:53:
DAVE86 wrote on 2023-05-31, 11:42:
Tetrium wrote on 2023-05-31, 10:29:

Is your POST diagnostics card new or did you have it for a while before it went faulty?

It's from Ebay. Single chip (CH311L) 2015. PCI/ISA type. I have a bunch of different ones. After the accidents I tried it in a crappy P3 board and it couldn't post with the diag card. Shut it off immediately. Never going to use this one ever again.

Was the card like this? I hope it is not common that this diag cards cause such damage.

Yes that's the one. I didn't expect it to go bad. Something got shorted internally. I remember from the very begining it never worked in ISA slots, showing post codes that is. Just as a voltages present indicator.
Other chinese POST diag cards that has gals/pals/logic, etc never failed me thankfully...

Reply 10 of 19, by DAVE86

User metadata
Rank Member
Rank
Member
Deunan wrote on 2023-05-31, 18:45:

As for the lifted pads, could be weak glue on the PCB. I don't deal with BGA often (in fact I try to stay away from such packages, not enough experience with those and no access to Xray machine to inspect the soldering job afterwards) but I've seen pads that come off the PCB with temperatures that were not excessive. Could be too long heating or not enough thermal soak from the bottom preheater but frankly there is always some risk with PCBs that have seen a lot of thermal cycles.

Of course such things show up on the one board that has the nicer features... I've seen some Nforce2 based motherboards that had both the north and south bridge heatsinked. Gigabyte and Asus didn't seem to bother.

Reply 11 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

Managed to get two badly beaten up abit boards as donors. It was a bargain and hopefully the southbridge chips are fully functional.

DSCF8983.jpg
Filename
DSCF8983.jpg
File size
485.35 KiB
Views
1780 views
File license
Public domain
DSCF8984.jpg
Filename
DSCF8984.jpg
File size
470.95 KiB
Views
1780 views
File license
Public domain
DSCF8987.jpg
Filename
DSCF8987.jpg
File size
508.26 KiB
Views
1780 views
File license
Public domain

So I have two reballed chips.
Haven't got the time to place them on the patient boards though...

Reply 12 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

Fixed up the solder mask.
file.php?mode=view&id=167851

Chip on the board
file.php?mode=view&id=167852

Aaaand both boards are still as dead as doornails. Either the chips were dead to begin with or I screwed something up. Anyway it was an interesting experiment.

Attachments

  • DSCF9002.jpg
    Filename
    DSCF9002.jpg
    File size
    522.31 KiB
    Views
    1694 views
    File license
    Public domain
  • DSCF8999.jpg
    Filename
    DSCF8999.jpg
    File size
    424.12 KiB
    Views
    1694 views
    File license
    Public domain

Reply 13 of 19, by rasz_pl

User metadata
Rank l33t
Rank
l33t

might be worth investigating that post card to see what got shorted to what?
is 3.3V supply working on those boards right now? maaaybe there are fuses popped somewhere? or PCI clock buffer chip?

https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
https://github.com/raszpl/440BX Reference Design adapted to Kicad
https://github.com/raszpl/Zenith_ZBIOS MFM-300 Monitor

Reply 14 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

Thanks for the tips! I have injected 5V into that post card and the voltage appeared on some of the data bus pins (where it shouldn't I guess). I haven't examined it further.
I'm bummed out on these boards right now but will probably get back to them in the future...

Reply 15 of 19, by treeman

User metadata
Rank Oldbie
Rank
Oldbie

The pads usually rip when all the solder has not been fully liquified under the chip, when you pull off the chip do you first gently touch it to see if it floats then take it off?

How do you prepare the chip that goes back on?
The pads on the replacement chip need to be wicked off from the old solder then add some solder paste with a stencil, wipe it down then use the heat gun to create solder balls on the pads

Reply 16 of 19, by Horun

User metadata
Rank l33t++
Rank
l33t++
DAVE86 wrote on 2023-06-01, 07:40:
janih wrote on 2023-05-31, 17:53:
DAVE86 wrote on 2023-05-31, 11:42:

It's from Ebay. Single chip (CH311L) 2015. PCI/ISA type. I have a bunch of different ones. After the accidents I tried it in a crappy P3 board and it couldn't post with the diag card. Shut it off immediately. Never going to use this one ever again.

Was the card like this? I hope it is not common that this diag cards cause such damage.

Yes that's the one. I didn't expect it to go bad. Something got shorted internally. I remember from the very begining it never worked in ISA slots, showing post codes that is. Just as a voltages present indicator.
Other chinese POST diag cards that has gals/pals/logic, etc never failed me thankfully...

Those single chip Diag cards are true garbage ! There are other topics here all about how crappy they are and should be avoided at all cost (unless you like to fry yer boards). Just saying the 5 chip versions are the best like you say

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 17 of 19, by DAVE86

User metadata
Rank Member
Rank
Member
treeman wrote on 2023-07-07, 00:25:

The pads usually rip when all the solder has not been fully liquified under the chip, when you pull off the chip do you first gently touch it to see if it floats then take it off?

How do you prepare the chip that goes back on?
The pads on the replacement chip need to be wicked off from the old solder then add some solder paste with a stencil, wipe it down then use the heat gun to create solder balls on the pads

The original and replecemnt chips were floating nicely before I took them off. On the replacement chips I used a stencil and leaded balls. I do bga work often altough not as "big" as a nf2 southbridge. I was suprised it didn't work out on either boards. As rasz_pl suggested there must be something else broken on the boards.

Reply 18 of 19, by treeman

User metadata
Rank Oldbie
Rank
Oldbie

sounds like you know what to do, I have never done bga on anything bigger then mobile phone pcbs but suspect this is where the problem is. The heatgun you are using may not be delivering enough heat, altho when the chips are floating it usually means its all ok to move.

Maybe the age of the hw also has something to do with the thermal resistance of the epoxy under the pads being weak, if those are all non connected pads? Taking a guess and also veering off the topic.
Thats all from me

Reply 19 of 19, by DAVE86

User metadata
Rank Member
Rank
Member

I didn't do anything differently with the boards during the reworks. The Gigabyte GA-7n400 Pro2 board have probably gone through many stressful thermal cycles during operation. The other boards let go of the SB chips fine.