Thanks for your prompt response. I un-select <echo typed characters locally> on the "ASCII Setup" tab of the HyperTerminal configuration to resolve character repeat/echo problem...see...
First IPL of used P550 in Home Lab displayed this on Control Panel: Line-1(01 M F), Line-2(HMC=0 T). Issue #1: Changed "01" to "02" and "M" to "N" on line-1, but IPL failed; no change on display...