Finding the pinout would only be the start of your problems - it appears to be controlled serially by the 89C51 processor. Not too many of those pins appear to be connected so determining the serial data connections would be fairly straightforward (use the datasheet for the processor to determine the UART pins). The processor is probably coded for the particular display output so although you might be able to determine the data to adjust the 'bars' you won't get access to the whole display (on a per-segment basis) unless you're prepared to recode the processor.