Voltage Regulator - Nixie Clock ITS1A Manual

It is beyond the scope of this document to suggest ways of troubleshooting any problems.
Plug a Mini USB cable into the USB socket on the PCB. Plug the other end into a USB power supply.
Unplug it if you see smoke!
Test the voltages in the following order. If any step fails the test, do not continue with the other tests.
Instead trouble-shoot and fix the voltage that is incorrect before proceeding.
1. Measure the 5V test point.
2. Now check the voltage at the 50V test point. This should be around 45V (50V was optimistic).
3. Check the voltage at the 150V test point. It should be around 135V (i.e. 3x45V)
4. Check the voltage at the 100V R test point (not the 100V test point – note the R). It should be
around 100V ± 5V.
5. Check the voltage at the -300V test point. It should be around -270V (i.e. 6x45V).
6. Check the voltage at the -250V R test point (not the -250V test point – note the R). It should be
around -250V ± 8V.
Unplug the power supply. Monitor the voltage on the 150V test point. The 1MΩ bleeder resistor should
drain the 150V arm within a second. Monitor the voltage on the -300V check point (you will install a
bleeder resistor for this later). Only proceed once this has dropped to a safe level (e.g. <40V). You can
short it to GND to speed up the process, but this can cause sparks to fly!

Voltage Regulator

After this is soldered in, the HV power will be disabled until the ESP-01 is plugged in and enables it, so
you must perform the power test before doing this.
Solder in U1. This needs to be in the correct orientation. Use the photo below as a reference. You can
bend the legs so that it lays flat on the PCB as shown in the photo below:
Plug the power back in and check that you get 3.3V at the 3V3 test point.
ITS1A CLOCK
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