Okay, I got a chance to assemble these finally, and thanks again!

Here are ones that are left. On a few these I got several alternatives to what I had, but they were all longer!

Again, the point in every case where I already had the Spanish is that what I had won't fit in the box. Now, maybe they'll have to enlarge the box, especially if it's a character or two. But I think in some cases there must be something shorter that's understandable (even using an abbreviation or shortened word like "psswrd"). Remember, the whole screen should provide some context about what's going on.
Meaning: scan all channels
English: Scan All
Old Spanish: Buscar Todos
(this one we might have to expand the box, but is there anything?)
Meaning: set defaults
English: Defaults
Old Spanish: Opciónes implícitas
(how about just "Implícitas"?)
Meaning: old password
English: Old Password
Old Spanish: Vieja contraseña
Meaning: new password
English: New Password
Old Spanish: Nueva contraseña
(something like "N. contraseña" or "Nueva cont."? The whole screen is about passwords, so a shortened noun will probably be understood)
Meaning: parental rating for movie
English: Movie Rating
Old Spanish: Clasificación de película
Meaning: parental rating for TV program
English: TV Rating
Old Spanish: Clasificación de programa
(is there no shorter word than "clasificación"? And I assume that at least the "de" can go, right? Will someone understand "TV"? Icons is a great idea, I'll check on that.)
Meaning: Key in new password & Enter to change password
English: Key in new password & Enter to change password
Old Spanish: Para cambiar la contraseña, entre la nueva contraseña & ENTER
New Spanish: Ingrese la nueva contraseña y pulse ENTER para cambiarla
(can the "la" be deleted, and the "y" replaced with a comma?)
Meaning: set all settings to their defaults
English: Set all to defaults
Old Spanish: Revolver a la configuración implícita
(how about just "configuración implícita"?)
These are the ones I think are fine:
Meaning: scan for new channels only
English: Update
Old Spanish: Añadir nuevos servicios
New Spanish: Actualizar
Meaning: foreground color
English: FG Color
Old Spanish: Color del primer plano
New Spanish: Color PP
Meaning: background color
English: BG Color
Old Spanish: Color del fondo
New Spanish: Color F
Meaning: foreground opacity
English: FG Opacity
Old Spanish: Opacidad del primer plano
New Spanish: Opacidad PP
Meaning: background opacity
English: BG Opacity
Old Spanish: Opacidad del fondo
New Spanish: Opacidad F
Meaning: enter password
English: Enter Password
Old Spanish: Entre la contraseña
New Spanish: ¿Contraseña?
Meaning: reset
English: Reset
Old Spanish: Reinicializar
New Spanish: Reiniciar
Meaning: reset password
English: Reset Password
Old Spanish: Reinicialización de la contraseña
New Spanish: Reiniciar contraseña
Meaning: locally used cable system plan
English: Cable Plan
New Spanish: Tipo [de] contrato
Meaning: picture shape (i.e. letterbox, fullscreen, etc.)
English: Picture Shape
New Spanish: Forma [de] imagen
Meaning: enter to switch to analog television menu
English: Enter to access ATV menu
New Spanish: enter para acceder [el] menu [de] TVA
Meaning: enter to set time based on information in current program
English: Enter to set time from stream
New Spanish: Fijar fecha [de] acuerdo con [el] programa
Meaning: set current month
English: Set current month
New Spanish: Definir el mes
Meaning: set current date
English: Set current date
New Spanish: efinir la fecha
Meaning: set current year
English: Set current year
New Spanish: Definir el año
Meaning: set current hour
English: Set current hour
New Spanish: Definir la hora
Meaning: set current minute
English: Set current minute
New Spanish: Definir los minutos
Meaning: set AM or PM time
English: Set AM or PM
New Spanish: Definir a AM/PM
Meaning: set local time zone
English: Set time zone
New Spanish: Definir la zona [horaria]
Meaning: set daylight savings time to observe or not
English: Set DST to observe or not
New Spanish: Definir horario de verano