Sir Sandman11 . . . . .
( Mr Sandman . . . bring me a dream.)
https://www.youtube.com/watch?v=CX45pYvxDiA
You are showing some hefty power supplies . . . .
Methinks that, instead, you will need to track down the units BIG logic board,that will just be bristling with DIP I.C.'s and look for a lithium battery that is hard wired onto the board . . . . . or in your case, the info / alert says that it is using two separate batteries.
I give you a depiction of an approximation of what you are looking for, but hit us with a good close up pictue of your units like board, if being uncertain.
https://i.postimg.cc/hSDQycpx/Lithium-Memory-Battery.png
On this particular board, it has its own built in board power supply.
See the PINK boxed connector, it connects to the boards power transformer to its right,.
Then the 6 diode to its left make DC power to supply your Power Electrolytic-Capacitors, cluster of 4.
Then there is one minor regulated power supply outputting at the black finned heat sinked semiconductor.
BEHOLD! at the 10 o'clock position from that unit is located THE conventional Looooooong life Lithium battery.
Not exactly being the well known rechargeable Li ion battery but the old conventional chemical lithium battery.
It trades chemical lo o o o o o o o ngevity for rechargeability.
Your unit seems to have aged and had its voltage output drop to the point of only enough voltage being able to hold some critical chips memory retention..
The unit is centered within the YELLOW rectangle mark up, and soldered in and has + lead polarity marked on its left.
Its assigned designator of BT1 is even telling you something. . . . . BATTERY
MY . . .first effort would be to take a voltmeter and check the units present state of voltage output.
Expecting it to have dropped downwards of 2VDC.
Next you GET the replacement battery ON HAND, you DON'T pull it and start looking for one .
Take your new battery and test its voltage then drop a 27---33 or 47 ohm resistor across it for some loading, then retest voltage, bveing loaded to see if it was not being an OLD stock battery .
I next get 2 common AA or AAA batteries which would put out 3V in series connection, either in a battery holder or I usually just
use hook up wire to interconnect by soldering with a HEFTY iron. Their two end wires present the resultant 3V.
This shunting battery gets its properly oriented (polarity wise) and is solder tacked to the very edge of the two pads that the old cell uses
for its leads.
FLASH MESSAGE . . . . . . familial request for automobubble road assistance . . . . will have to continue, a bit later . . . tune in later, same time, same station.
73's de Edd. . . . . .
I wonder now . . . . . . . Do infants enjoy infancy, as much as some adults enjoy adultery ?
