There is a Sony IC which is a 22pin 400mil package and is a 1k x 8bit SRAM that is not all that common, but is quite often faulty when found these days. It can be replaced with the more common 24pin 300mil 2k x 8bit SRAM such as the 6116, but requires that some of the pins are rewired due to the different packages.
The above image shows the pinouts of the 5808 along side the 6116.
You will notice that by moving the 5808 down 1 pin along side the 6116 that all the pins up to pin 16 match up. So the only pins that need to be changed are those below.
pin1 on the 6116 goes to pin21 on the 5808
pin 18 on the 6116 goes to pin18 on the 5808
pin19 on the 6116 goes to Gnd
pin20 on the 6116 goes to Gnd
pin 21 on the 6116 goes to pin17 on the 5808
pin22 on the 6116 goes to pin19 on the 5808
pin23 on the 6116 goes to pin20 on the 5808
pin24 on the 6116 goes to pin22 on the 5808