Siemens · SIMATIC Basic / 177 series
6AV2123-2JB03-0AX0 Repair
Siemens SIMATIC KTP900 Basic (6AV2123-2JB03-0AX0). The dominant board-level failure across SIMATIC panels is the power supply (aged electrolytics), with touch and backlight wear close behind — all repairable with the WinCC project preserved.
Known failures on the 6AV2123-2JB03-0AX0
- ▸Dead unit / will not power on
- ▸Powers on then restarts
- ▸Touch not responding
- ▸Dark or dim display
Ship your unit to
USPS
Control Board Lab
PO Box 120241
Arlington, TX 76012
UPS / FedEx
Control Board Lab
1009 Oakwood Ln # 120241
Arlington, TX 76012
Write your RMA number on the outside of the box and include it on a note inside. Units over 50 lb (large VFDs, spindle drives, industrial PCs in enclosures) ship by freight — contact us before ordering and we will arrange dock-to-dock shipping.
Check these before you ship
Some of these will tell you the 6AV2123-2JB03-0AX0 is fine and the fault is elsewhere — worth ten minutes before you pay to ship it.
- □Confirm the supply feeding the terminal is actually delivering its rated voltage under load — a failing panel supply mimics a dead HMI exactly.
- □Shine a bright light at an angle across a dark screen. If you can make out the application faintly, the LCD is alive and you have a backlight fault, which is a cheaper and faster repair.
- □If the unit boots but the touch is wrong only in one region, note where. Localized dead zones point at digitizer wear; whole-screen drift more often points at the controller.
- □Note the exact text of any boot or fatal error. The code narrows the fault far faster than "it will not start".
Not your exact model?
Search the catalog or send us the number on your unit's label — we service far more than the catalog shows.
How the 6AV2123-2JB03-0AX0 differs from the rest of the SIMATIC Basic / 177 series range
These share an electronics platform and fail in the same ways, but they are not interchangeable — check the number on your unit's label against this list before you ship, and before you buy a replacement.
| Part number | Distinguishing spec | Repair | |
|---|---|---|---|
| 6AV2123-2JB03-0AX0 (this page) | SIMATIC Basic / 177 series | $349 | |
| 6AV2123-2GB03-0AX0 | SIMATIC Basic / 177 series | $349 | View → |
| 6AV2123-2MB03-0AX0 | SIMATIC Basic / 177 series | $349 | View → |
| 6AV6642-0BA01-1AX1 | SIMATIC Basic / 177 series | $349 | View → |
| 6AV2123-2DB03-0AX0 | SIMATIC Basic / 177 series | $349 | View → |
Why a 6AV2123-2JB03-0AX0 fails — and what we do about it
The SIMATIC Basic / 177 series shares its electronics across the family, so these are the faults we see on this part number again and again.
Touch digitizer failure
- What you see
- Unresponsive touch, drift, or dead zones on part of the screen.
- Why it happens
- The touch layer and its flex connection wear with use, concentrated where operators press most often.
- What we do
- The digitizer is replaced and calibration verified across the full screen area.
Backlight failure
- What you see
- Dark screen with a faint image still visible under a bright light.
- Why it happens
- The backlight and its driver circuit degrade with running hours while the LCD and video path remain perfectly serviceable.
- What we do
- Backlight and drive circuitry are repaired and even brightness confirmed.
Repair or replace a 6AV2123-2JB03-0AX0?
Operator terminals are the clearest repair-over-replace case in a plant. Much of the installed base is discontinued with no drop-in successor, so replacing means specifying new hardware, re-developing or converting the application, re-testing it against live machinery, and retraining operators on a screen that behaves differently. The repaired terminal drops back into the same panel cutout running the same application. Even where a successor exists, the migration engineering usually costs several times the repair.
Full technical detail for this repair
The Siemens Basic / TP177 / OP177 service page covers the complete bench sequence — how the unit is tested, what gets replaced and how it is proven before it ships back — along with the rest of the family we service.
Siemens Basic / TP177 / OP177 Repair — full details →Frequently asked questions
Can the 6AV2123-2JB03-0AX0 be repaired?
Yes — dead unit / will not power on, powers on then restarts, touch not responding are the failures we commonly repair on the SIMATIC Basic / 177 series platform. The flat price is $349 including parts, testing, and the 24-month warranty.
How long does a 6AV2123-2JB03-0AX0 repair take?
Standard bench time is 3–5 business days once the unit arrives. Rush service (+$149) moves it to 1–2 business days, and emergency same/next-day attempts are available — contact us first.
How do I send it in?
Start the repair online to get an RMA number instantly, pack the unit well with the RMA on the box, and ship it to our Dallas–Fort Worth lab with any carrier. Full packing guidance is on the mail-in instructions page.
Machine down? Let's get it back up.
Start a repair online in two minutes, or send us the part number for a free technician review.
The Fixed-or-Free Guarantee: if we can't repair it, you don't pay for the repair.
Call (817) 799-7332 · 📱 Text us a photo of your unit · Email repairs@controlboardlab.com