I'm working on a RSA3308A that has a dead front panel. The only button out of 65 that works is the power key. I can control the SA using the Windows software control panel GUI now, after some major re-installs and XP rework, and the unit is otherwise functional except for the hardware front panel controls. I have probed the panel keyboard circuit (PCB A60), a fairly simple board consisting of an Altera Max EPM7256 PLD which I believe is acting as an I/O expander for what looks to be perhaps a 18 pin DIP style PIC processor. (the DIP has a label covering the part number so I'm not certain it's a PIC). The only things that seems alive on the front panel PCB are the two power rails (+5 and +3.3) and the 10 MHz clock. I see no other activity on the scope when the pins of the micro are probed and keys are pressed. There is a multi-pin connector wired to the main backplane board from the front panel. and again when the connector pins are probed, nothing except the power supply voltages are seen. I suspect that either the micro or PLD may have been zapped by ESD, but I have no history at all on this unit. Unfortunately, both devices on the FP board are programmed, and without the firmware, they can't just be replaced,
I don't think it's a software problem. There are no detected devices missing a driver as displayed by the device manager in XP. There is a software service named "WPA200 front panel" that is set to start automatically by the OS, It likely only starts when the hardware is detected. The service is not auto starting, but can be forced to start manually, and it does so successfully, but without any joy. The front panel is still dead with the service running...
Does anyone have experience with repairing and, especially obtaining parts for these units? Any donor candidates out there by chance?
I would like to find a known working front panel PCB, p/n 671-B156-50 or 389-B158-50. Can anyone help? Tek appears to have no parts for these units, as far as I can tell. Fleabay has been a bust so far. The 3300 series is from the early 2000's, but still a viable and very useful tool, if not a bit of a boat anchor, size and weight-wise.
Any suggestions regarding additional troubleshooting are welcome as well.
Thanks.
