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A31p Resistor Replacement
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steve5214
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Joined: 07 Jan 2006
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PostPosted: Fri Sep 08, 2006 4:43 pm    Post subject: A31p Resistor Replacement Reply with quote

Victor,

This one totally confuses me.
I bought a faulty A31p, after a lot of head scratching and examination I found that a resistor was missing( or I presume resistor as the board is marked R*). So to begin with I solder wires to the pads to allow me to interchange resistors without too much stress to the board.If I short them at the right time it boots perfectly. Starting with bread board and cheep resistors I begin testing and find that above 9k1 I get security tamper error,below i get continuous beeps, at around about 9k1 I can at times get it to boot/stall at splash screen/blank screen but if i boot it then it will reboot ok many times on test but if left off for 15mins back to security error.
Looking for solution I tried 9k1 1% thin metal film resistor straight to board (no wire) same result then 9k1 smd resistors still same result.
Any thoughts ?
Its really puzzling me and annoying .. Rolling Eyes I could easily use a switch but its personal now Exclamation
Cheers
Steve
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victor
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PostPosted: Sun Sep 10, 2006 8:57 pm    Post subject: Reply with quote

Hm, quite interesting. Are you sure it is an R? It could be a capacitor..the sympthoms make me think is an electrolytic perhaps. Small SMD elcos look exactly like resistors, just the color is different.

9k1 resistors are not in the standard, and anyway just guessing is not a convenient solution. If you would post a picture of that, I could ask some of my contacts to take a look on a good board.
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steve5214
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PostPosted: Mon Sep 11, 2006 6:49 pm    Post subject: Reply with quote

Victor,

I dont have any pics of it at the moment, ill try and get some. Its actually on the security chip daughter board itself, with the Atmel AT97SC3201 on it that plugs onto the main board "P/N 26P8193". Its an A31P type 2653-RQG these have the security chip matched to the board and arent interchangable as some others are. The component is deffinitely marked as R2. There are also R1,C1 and C2.

Cheers
Steve.
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victor
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PostPosted: Mon Sep 11, 2006 9:36 pm    Post subject: Reply with quote

I will try to get some info on this. Right now we are in preparations to start working on these 3201 and 3203 chips. A US customer has about 20 or more boards with wrong TCPA subsets and we need to find a way to re-pair (I mean pairing) the chips with the boards.

I will see what I'll find. What is the error you subsequently get more often? It is 0192?
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steve5214
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PostPosted: Mon Sep 11, 2006 10:23 pm    Post subject: Reply with quote

Victor,

I'm have also been looking into this with A30's, and I believe that I am already cirumventing the chip tamper checks, but will be better informed later this week I hope (another one on its way). Im not sure what the time limit is on chip removal before we get the 0192 error and I couldnt find any info on the "xtamper" input/output function but if you ground xtamper as soon as you get the splash screen then the system will boot and run perectly!! . As I say I cant verify at the moment that this will allow chips to be interchanged just yet but hope to soon. You boys being up on the electronics should be able to find something to facilitate the grounding/timing I hope.

Cheers
Steve.
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TP-Guy
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Joined: 15 Jan 2006
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PostPosted: Thu Sep 14, 2006 6:32 pm    Post subject: A31p Resistor Replacement Reply with quote

Steve:
The position R2 on the normal TCPA sub-card has NOTHING installed.

The end points are soldered but there is no resistor.

The A30 allows you to remove the security chip and restart, go into the BIOS and reset the security error.

Those chips are not keyed to a specific system board and they only contain up to 4 encrypted keys. Nothing like the sub-card used later on the other models.

Are you sure you are using the correct TCPA sub-card for the A31p? All of the chips I have seen on that model are an early version and are removeable as long as you don't install the later BIOS.

The sub-card you are describing is from a T30, T40 or R32. I don't think it will work with the A31p.

I will dig out a spare A31p that is a model "R" and see what chip is installed.
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steve5214
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PostPosted: Thu Sep 14, 2006 7:41 pm    Post subject: Reply with quote

TP,
This is an A31P 2653-rqg which is chip specific and runs perfectly.
Cheers
Steve
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TP-Guy
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PostPosted: Thu Sep 14, 2006 8:29 pm    Post subject: Reply with quote

What did you do to make it run perfectly? your last messages were saying it wouldn't finish POST.
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steve5214
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PostPosted: Thu Sep 14, 2006 10:11 pm    Post subject: Reply with quote

TP,
This isnt how the thread started and it seems to me that maybe I posted this before I should have and maybe I should finish my research totaly before posting.
Cheers
Steve.
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TP-Guy
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PostPosted: Thu Sep 14, 2006 10:19 pm    Post subject: Reply with quote

Steve:

I understand. I have only seen the listings right here and it wasn't real clear what you were trying to do.

I am working on finding a way to divorce TCPAs and System boards so I cn remarry other TCPA to the boards.

A lot of boards ended up in the repair supply chain with their TCPA missing and shops ended up with bags of TCPA sub-cards.

I asked Victor if he had looked into the topic and he referred me to this area.

I don't have any great break-throughs, but I am shovelling my way through mis-information from Atmel and IBM.

Since IBM can do the task, there has to be a solution for me too.

Let me know if you find out anything that will help.

TP
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victor
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PostPosted: Thu Sep 14, 2006 10:27 pm    Post subject: Reply with quote

I have to admit that is a bit confusing.

So, I understand that initially you had a problem with the A31p. The problem you thought you have with the TCPA sub-board, where apparently a resistor is missing. I asked TP-guy to take a look at one board he had (thanks TP-guy !) and he answered here that the daughter board usually hasn't any resitor in the place you mentioned. I hope this helps a bit.

I just want to mention that if the chip is AT97SC3201 then it could be pairing with the motherboard (is chip specific as you said), but only if the BIOS version it was the right version. In fact the BIOS code decides if there is an error to show or not (0192) and if that error could be reset.

In rest, the older chips AT90SP0801, bah..
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steve5214
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PostPosted: Sat Sep 16, 2006 10:37 am    Post subject: Reply with quote

Victor,
I had the laptop booting but thought it looked like there was a component missing, thanks TP you cleared that one up for me.



These are taken with mobile phone so not great quality ..but they show m/c type and serial number and bios version....all match ...and also the 0192 error then it bypassed to windows

Cheers
Steve.
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steve5214
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PostPosted: Sat Sep 16, 2006 10:44 am    Post subject: Reply with quote

Victor,
The chip is atmel AT97SC3201 3H5151
Cheers
Steve.
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steve5214
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PostPosted: Sat Sep 16, 2006 6:50 pm    Post subject: Reply with quote

By the way if either of you can point me in the direction of a cheap motherboard and un-paired chip or just chip would do to test against my board Id be very gratefull. Allthough that are as TP says plenty of useless ones around no one seems to want to part with them.

Cheers
Steve.
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steve5214
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PostPosted: Fri Sep 22, 2006 10:32 pm    Post subject: Reply with quote

Victor,TP,
I take it from the lack of response that you are both trying to figure out how to do it .
Cheers
Steve.
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