I dimly recall that the blink pattern is actually a series of 8 flashes that is a binary number representation in least significant bit order corresponding to the error condition. I think (and I'm going off a dim memory here, as I haven't worked on a Toshiba in a good long while, so I may be wrong here) that a short blink lasts 0.5 seconds, and a long blink lasts 1 second. You have to write out the entire blink sequence (which will repeat itself every 8 flashes separated by a 2 second "off" period), then convert it to a binary number, then convert the binary to a hexadecimal representation. Once you have the hex error code, you should be able to google for error code on your A55 model to figure out what it is.
An example of what to do:
1) Say the blink code is short-long-short-short-long-short-short. Write down "SLSSLSS" as it blinks. Double-check the code to make sure you got it right.
2) Replace each S with a 0, and L with a 1 in the blink sequence - i.e. SLSSLSS becomes 0100100
3) The computer is generating the blink code in least significant bit format. To properly convert the blink code to the actual binary error code, separate it out in to two digit blocks 01 00 10 00. Rewrite, reversing the order of the numbers from right to left: i.e. 01 00 10 00 becomes 00 01 00 10 - (i.e. 8th number reading from left to right becomes first number of binary code, 7th number from left to right becomes 2nd number of binary code, etc, down to first number reading from left to right being last number of binary code) -->this resulting number is the true binary representation of the error code the blink code represents.
4) Use a binary to hexadecimal converter: 00 01 00 10 binary is 12h (in hexadecimal).
5) You'd then do a google search for your model number and error 12h and hope something comes back. Toshiba has removed the service manuals from their website (they consider the blink codes to be proprietary dealer information and no longer release them to the public), but the info is still mostly out there (though there may be some variation between models, most of the codes tend to be consistent between models).
Use the same process with your blink code, and with luck it may point you to the actual problem.
Hope this helps.