Alarm started beeping and displayed BF check on the display screen

SOURCE:Scales show weight in kg. How to get them to show lbs.
Body Fat Monitor/Scales: TBF-611, TBF-612, TBF-621, TBF-622, BF-541, TBF-560, TBF-572. UltimateScales: 2000, 2001, 2001T. BF-662, BF-555, BF-556, BF-558, BF-559, BF-625, BF-626.
Press the Set and Up Arrow buttons at the same time. Release the buttons, the display will flash. Press the Arrow button to cycle through each weight mode until just the mode that you require is displayed. Then press Set. The display screen will flash to confirm your selection and store in memory.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.

high low voltage board were likely not needed
board registers high temp and after a few days of constant high temp alarm will restart
by replacing low volt board all you did is start with empty register also when replacing low volt board they have to be programed for your model
sounds like you need service for your cooling issue

"bf" stands for "Back up failure. Your system communication to the monitoring station is working on phone lines only if it's tied into them. I would call the monitoring station and see if it's still communicating.

Alarm settings can be made with clock/radio on or off.
The Alarm Clock/Radio is equipped with two independent alarm
systems each of which can activate the Human Wake System Buzzer
or turn on a preselected radio station.

Using Alarm with a Preselected Radio Station:
Select desired station using + or - Tuning Button [18] or select one
of the 1-7 presets.
Set the desired volume level using Alarm Level Adjustment [9]
Select alarm system 1 or 2 by pressing the alarm button [14] or [15].
Display will blink with selected alarm
Press alarm set button [16]
Display will blink showing selected alarm hour and alarm mode
and beep
Press alarm Mode button [20] to select alarm mode
Use + or - button [18] to set alarm time hours.
Press set button [16] to set minutes using + or - button to
set minutes.
Press alarm days selections 1-7 (Sunday-Saturday) to select
alarm days.
Display will show the days on which you wish to be awoken by the
radio alarm.
Pressing alarm button 1 or 2 will confirm settings and a beep and
display indicates radio alarm is set.
Note:
If alarm days or alarm mode are not selected display will blink
all the days for a few seconds indicating the alarm is not set
and the alarm will not be activated.
If you would like to be awoken to the station you are presently
listening to press alarm button 1 or 2 for more then 2 seconds.
This allows the station you are listening to be stored into
memory. Then follow above procedures.

Using Alarm with HWS Alarm Beep:
Select alarm system 1 or 2 by pressing the alarm button [14] or [15].
Display will blink with selected alarm Press alarm set button [16]
Display will blink showing selected alarm hour and alarm mode
and beep
Press alarm Mode button [20] to select alarm mode
Use + or - button [18] to set alarm time hours.
Press set button [16] to set minutes using + or - button to
set minutes
Press alarm days selections 1-7 (Sunday-Saturday) to select
alarm days.
Display will show the days on which you wish to be awoken by the
buzzer humane alarm
Pressing alarm button 1 or 2 will confirm settings and a beep and
display indicates buzzer humane alarm is set.
Note:
If alarm days or alarm mode are not selected display will blink
all the days for a few seconds indicating the alarm is not set
and the alarm will not be activated.

Cancelling Alarm Setting:
Alarm functions can be cancelled:
Select alarm system 1 or 2 by pressing the alarm button [14] or [15].
Display will blink with selected alarm
Press alarm set button [16]
Display will blink showing selected alarm hour and alarm mode
and beep
Press alarm Mode button [20] one or two times (depending if you
were in the alarm radio or alarm buzzer mode) till display blinks.
Press alarm 1 or 2 button again to confirm alarm cancellation.
The symbol will stay on the display for about 2 seconds
and disappear.
You may also select days you wish to be or not to be woken after
pressing the Set button while display is blinking. Press 1-7
(Sunday-Saturday) of button [19] to make a selection.

This is the figure of your device and you can find which button where is:




Good luck!
Thanks.
gylacz

Since your problem started with a battery change, I am going to assume that method 1 is most likely going to fix your problem...Good luck!



Method 1
Press the Set and Up Arrow buttons at the same time. Release the buttons, the display will flash. Press the Arrow button to cycle through each weight mode until just the mode that you require is displayed. Then press Set. The display screen will flash to confirm your selection and store in memory.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.
Method 2
Body Fat Monitor/Scales: BF-542, TBF-551, TBF-521, TBF-531, BF-681, BF-682, BF-679, BF-680, BF-578, all Ironman products, and all InnerScan products.
Select the preferred weight mode by using switch on the back of the measuring platform.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.

coul be ram or videocard
try to clean the motherboard, maybe dust is causing your problem

Q: Why does "st-lb" or "kg" appear when taking a measurement?
A: The unit's "Weight Mode" has been set to measure your weight in units of stone-pounds (st-lb) or kilograms (kg). Tanita's Body Fat Monitors and the UltimateScales can measure weight in three different modes: lb (pounds), kg (kilograms) or st-lb (British stone-pounds). To change the setting, first find out which model you have (it should be written just above or below the display screen of the unit).
Method 1
Body Fat Monitor/Scales: TBF-611, TBF-612, TBF-621, TBF-622, BF-541, TBF-560, TBF-572. UltimateScales: 2000, 2001, 2001T. BF-662, BF-555, BF-556, BF-558, BF-559, BF-625, BF-626.
Press the Set and Up Arrow buttons at the same time. Release the buttons, the display will flash. Press the Arrow button to cycle through each weight mode until just the mode that you require is displayed. Then press Set. The display screen will flash to confirm your selection and store in memory.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.
Method 2
Body Fat Monitor/Scales: BF-542, TBF-551, TBF-521, TBF-531, BF-681, BF-682, BF-679, BF-680, BF-578, all Ironman products, and all InnerScan products.
Select the preferred weight mode by using switch on the back of the measuring platform.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.

Body Fat Monitor/Scales: TBF-611, TBF-612, TBF-621, TBF-622, BF-541, TBF-560, TBF-572. UltimateScales: 2000, 2001, 2001T. BF-662, BF-555, BF-556, BF-558, BF-559, BF-625, BF-626.
Press the Set and Up Arrow buttons at the same time. Release the buttons, the display will flash. Press the Arrow button to cycle through each weight mode until just the mode that you require is displayed. Then press Set. The display screen will flash to confirm your selection and store in memory.
Note: If weight mode is set to pounds or stone-pounds, the height programming mode will be automatically set to feet and inches. Similarly, if kilograms is selected, height will be automatically set to centimeters.

Okay I have this module so here goes.
Start from your regular timekeeping mode (use lower left buttin to cycle through until you get to the normal time display).
Press 'mode' button (lower left) once. You are now in alarm mode.
Press lower right button to cycle through the alarm modes. The cycle goes: hourly beep on, timed alarm on, both on, neither on. You will see the corresponding icons (a ripple icon for hourly beep and and a bell icon for the alarm) appearing/disappearing in the top left of your display as you cycle through. So if you are in hourly beep mode now you probably need to press that lower right button 3 times to get to 'neither' alarm being on.
Press lower left button to return to normal display.
Hopefully - enjoy the peace!

After selecting either TIME, DATE, or ALARM at the top of the screen, use the stylus to touch and hold the large time display. Hold it there for about 5 seconds and the clock will beep and the time display will start flashing. Then you can touch either the hours or minutes and it will increase by either 1 hour or 1 minute accordingly. When the DATE is selected, it shows the year in the large display. Again, holding the stylus on the year diaply for about 5 seconds will enter into the chqange mode. IN all cases, to exit the change mode simply select one of the other selections across the top: TIME, DATE, ALARM.