Troubleshooting Star TSP143IIIU USB receipt printers with Seamless POS

1. What this guide covers

This article helps you fix printing issues with the Star Micronics TSP143IIIU when it is connected by USB (charging cable) to your iPad.

You will learn how to:

• Read the printer status lights

• Do basic hardware checks (power, paper, jams)

• Check the USB connection and iPad settings

• Confirm the printer and print streams are set up correctly in the Seamless POS back office

2. Quick checklist

If your TSP143IIIU has stopped printing, work through this list in order:

1. Check power

   • Is the power cable fully seated at the back of the printer and at the wall or power strip

   • Is the blue Power light on

2. Check paper

   • Open the lid and make sure there is an 80 mm thermal paper roll

   • Paper should feed from the bottom of the roll, towards you, not from the top

   • Close the lid firmly until it clicks

3. Check the USB connection

   • Make sure the USB cable is firmly connected to the printer and to your iPad adaptor / hub

   • If possible, test with another known good cable

4. Do a self-test print from the printer

   • Turn the printer off

   • Hold down the FEED button

   • While holding FEED, turn the printer on

   • Release FEED when it starts printing

   • The printer should print one or two test receipts with its configuration details

   
   If the self-test prints but Seamless POS does not, the issue is most likely connectivity or configuration, not the hardware.

5. Check printer configuration on the iPad

   • On the iPad, make sure the Seamless POS app is running on the device physically plugged into the printer

   • In the Seamless POS app, go to Settings and then Printers / Hardware

   • Confirm the Star TSP143 printer appears and is assigned to this device

6. Check print streams in the Seamless POS back office
   ​

   • In the Seamless POS back office (online dashboard), go to Menu → Printing / Print streams

   • Confirm:

     • The TSP143IIIU is listed as a printer

     • It is selected for the correct print streams (for example Receipts, Bar, Kitchen)

     • Each relevant POS device or register is linked to the correct print streams so tickets go to the right printer

7. If you still cannot print after these steps, move on to the detailed sections below.

3. Understanding the TSP143IIIU status lights

The TSP143IIIU uses two LEDs on the front:

• Power LED (blue) - left

• Error LED (red) - right

Here is a simplified guide to the most useful patterns:

Normal states

Common recoverable errors

Temporary over-temperature errors

Serious hardware errors

If you see both LEDs blinking together in a regular pattern, or the red light solid with no blue light, this usually indicates a hardware fault such as:

• Abnormal power supply voltage

• Sensor or memory error

In these cases:

1. Turn the printer off, wait 10 seconds, turn it back on.

2. Try a different power socket or surge strip.

3. If the same pattern returns, contact your hardware supplier for repair or replacement.

4. Hardware checks step by step

4.1 Power and cabling

• Confirm the power switch is on and the blue light is lit

• Check the power brick and cable are firmly plugged in

• Avoid plugging the printer into a socket that can be turned off accidentally (for example a wall switch behind the bar)

4.2 Paper roll and paper path

1. Open the printer cover with the release lever.

2. Remove the roll and check it is thermal paper, not plain till roll.

3. Reload the roll so it feeds from the bottom towards the front.

4. Pull a little paper out over the tear bar.

5. Close the cover until it clicks.

Press FEED to confirm paper advances smoothly.

4.3 Self-test print

The self-test confirms the printer itself is healthy:

• If the self-test prints but Seamless POS does not, the problem is app configuration, iPad connection or cable.

• If the self-test does not print, and the lights show an error pattern, focus on the LED table above or contact your hardware supplier.

5. USB and iPad connection checks

Because the TSP143IIIU is USB only, all printing depends on the USB link between the printer and the iPad.

1. Cable and adaptor

   • Use a good quality Apple-certified adaptor and cable where required

   • Try another cable if the iPad intermittently disconnects or stops charging

2. iPad sees a USB device

   • If the printer supplies power, the iPad may show it as charging when connected

   • If you use a hub or dock, try bypassing it and connecting directly

3. SeamlessPOS printer assignment

   • On the iPad, open SeamlessPOS

   • Go to Settings → Printers / Hardware

   • Make sure:

     • The Star printer shows as connected

     • It is assigned to this POS device or register

     • It is selected for the correct print streams (for example Receipts)

6. Back office print stream checks

In the SeamlessPOS back office, make sure:

• The TSP143IIIU printer exists as a hardware device

• It is linked to the correct print streams (Receipts, Kitchen, Bar, etc.)

• Each POS device / register is configured to use the intended print stream for the relevant actions (for example table orders versus takeaway orders)

If print streams are mis-configured, you might see:

• Tickets printing on the wrong printer

• Nothing printing at all for certain order types

7. When to contact support

Contact Seamless POS support or your hardware supplier if:

• The printer shows serious LED fault patterns even after a power cycle

• The self-test will not print

• You have followed all USB, iPad and back office checks and the printer still does not appear or print in Seamless POS

Provide photos of the printer lights and a copy of the self-test if possible, this speeds up diagnosis.