Nova Series LPSU Replacement

Preface: This article will cover Laser Power Supply replacement on Thunder Laser Nova series machines.

Before we begin:

The LPSU outputs somewhere around 30,000 VDC and can store a charge so always heed the big red wires and connectors. They are specially insulated but could still pose a hazard. The HV output does utilize a fly back transformer. Before working on the LPSU, let it sit unpowered for at least 1 hour.  The machine should be powered down and unplugged from the receptacle before begging work.

Tools Needed:

It would be good to gather up all the tools needed prior to starting the job. Since the LPSU is in the back of the machine, it may not be the most accessible so moving back in and out to go get tools may be a chore.

Required:

Small Green Flat Head Screw Driver

Red Phillips Head Screw Driver

Nova Door Key

Small Adjustable Wrench (For Nova 24 Ammeter Connection, Not Shown below)

Allen Key 3mm with Ball End

Optional:

Work light

Small Baggie for Bolts and Washers

Painters Tape and Sharpie

LPSU Removal Process:

Step 1: Power off and unplug the machine

Let it sit off and unplugged  for at least an hour.

Power of the Main Power Switch	Unplug the Main Power Cable

Step 2: Locate Power Supply for your machine

Nova 35, 51, and 63:

Located on the back of the machine, behind the blue door to the Left of the exhaust outlet

Back Of Machine	Behind the Left Blue Door

Nova 24:

Located on the left side of your machine behind the lower blue door.

Left Side Of Machine	Behind the Lower Blue Door

Step 3: Prepare the LPSU for Removal

Remove the Door for Easier Access	Mark the Bad LPSU with Tape and Sharpie
Pull down on the spring loaded pin to release the door. Set aside

Remove the Input Wiring

On the right side of the LPSU there are two green connectors. Grab them with your thumb and pointer finger, wiggle and pull out. (They are not screwed in).

Nova 24 LPSU	Nova 35,51 and 63 LPSU

Grab the sides of the Green Blocks	Both Input Connectors Removed
Wiggle the block up and down as you pull it out. Set aside.

Disconnect the Positive HV Wiring

Lift the HV connector out of the mounting bracket and unscrew the two halves

Loosen the Set screw on the Left and Lift out	Unscrew the two Halves

Disconnect Negative Wiring

Nova 24 (Back of Ammeter)	Nova 35, 51 and 63
Accessed from the back of the machine through the door to the right of the exhaust outlet	(White wire that goes to the 3 position terminal block next to the LPSU)

Step 5: Remove LPSU from the machine

For the Nova 24:

Loosen 3 Screws

(2 Shown here in the Black tabs, there is one more on the Right that is behind where the 3 pin power connector was) Slide the LPSU to the Left and remove form the mahcine.

For the Nova 35, 51 and 63:

Remove the 4 screws and washers that are holding the LPUs to the back panel. Place the screws in a bag for safe keeping.

Remove the Lower Screws	Remove the Upper Screws
(Remove the lower screws first, they are harder to access)	(Support the LPSU weight so that the screws are easy to turn and threads are not messed up)

Step 6: Reinstall LPSU:

Reinstall in the reverse order. 

Critical Watchout for Nova 35, 51 and 63 LPSU Replacement

Incorrect Termination Example	Correct Termination Example
(The white and black lines are not in-line. The tube may fire but the high resistance will cause arcing and thermal insult to the connector, the	(Black and White wires must be In-Line with each other)

Additional Resources:

Nova Series DSP TL Timer Mid 2022 Block Diagram v8.4

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