Looking for help on diagnosing Makerbot Replicator 2 electronics, etc.

[Mike Wirth]

Kind folks,

Managed to burn out IC U5 on the LCB/Button/SD-reader board of a Rep 2 (details here). This printer is owned by an educational non-profit, learningtech.org.  So we'd like to repair it for minimum cost.  Makerbot wants $80 for the whole control panel assembly (LCD, case, PCB, etc.). And the above referenced details say the IC is a microprocessor, so just replacing it is insufficient.  Would need to have the correct SD-card reader firmware loaded as well.  So have several questions for which I'm seeking answers and additional help:

1. What's the chip type of IC U5 on the control panel PCB?  If you have a Rep2, can you read the designation on the chip. (Might in fact just be a 5v-to-3.3v level converter for the SCL and SDA lines of the I2C interface to the SD card, not a micro.). Anybody have a schematic for this board? (or for the open-source Reprap with SD from which it was derived)?
2. Anybody know where just the PCB (not the whole control panel) can be obtained for under $80.  (My search in the "usual places" wasn't fruitful.)
3. Wonder whether the main controller board was fried, too. (No visual evidence, but...). Would like to verify if replacing the control panel would suffice to repair the Rep2.  This could probably be done with a board swap exercise with a working Rep2.  Anybody up for this?  Your decision as to whether we try my boards in your machine or vice-versa.
4. While I'm at it, learningtech.org also has a nonworking Replicator Mini; needs a new printhead assembly.  Best source?
5. Both learningtech.org and an offshoot are interested in acquiring a new printer or two for classroom use (mainly middle-school kids).  Besides the Make! magazine reviews, any recommendations.  Balancing tech favors with price is the issue.

TIA for your help to the educational community on the peninsula.

Mike