Are you shure your Multimeter is set correctly for measuring Voltages??? It should be set to “VDC”, “V=”, “DC=” whatever is imprinted and a range of 20 Volts. Have a look into the Manual or take a look here and here
What puzzles me is that it either shows 1 or 0 - 1 is normally “out of Range”. Please try measuring a working Battery just to compare the readings (no matter 1,5V 9V… whatever you have at hand)
OK… i have a similar one with slightly different Print (came with all the Pots i ordered for free ) so maybe its time to get another working one if DCV 20 doesn’t work…
On your photo, the red probe is plugged in the right hole for voltage, resistance and small current measurements (the useful stuff unless you are repairing washing machines). Maybe the battery is kaput?
First, i cant understand you measurements at the PSU. If you Put the Black Probe to the outer Ring and the Red one into the Plug you can only read ONE VALUE, right? Whats the 2nd Value for? Or are these first readings with the Black Probe to GND and then measureing the positve +5V and negative -5V Rail?
Thats perfectly OK. The reading depend a bit on the internal Battery Status for most cheaper Multimeters, so 1,54V means your battery is superok. What puzzles me is that the Voltage from the regulators is a bit high, it could be because there is no suifiicient Load to the Regulators. Try a 1K Resistor between the Positve / Negative Rail and GND an measure again. You then should be somewhere near the desired 5V.
Its the same as with the Motor in your Car: if you are in Neutral it reacts rather fast and with more RPM/Gas than while driving as the Car is a Load to the Motor. Same here with the 7805 and 7905 regulators. So put a resistor (say 1k or R470 or even R220) between the Power Rail and GND. You may simply stick it into one of the (hopefully) yet unpopulates Sockets. The Building Instructions show you the right Spots. With this load the regulator should show the correct Voltage and you can go on and proceed.