Repairing a Gottlieb System 80 Driver Board: Replacing a Burned-Out MOSFET and Decoder
Complete 2026 Guide — Specific to the GottFA80_Plus & GodRi80
Did your Gottlieb System 80 driver board catch a burned-out component? A MOSFET or decoder fried? In this complete guide, we'll show you how to repair your GottFA80_Plus or GodRi80 driver board yourself — by replacing an AP2310 MOSFET and/or a 74HC175D decoder.
⚠️ Important: this procedure applies only to GottFA80_Plus and GodRi80 boards. Original Gottlieb System 80 driver boards use different through-hole components and require a different procedure.
- ⏱️ 30–60 minutes
- 🛠️ Beginner to intermediate
- 💶 Parts cost under $5
⚠️ Before You Start: GottFA80_Plus / GodRi80 vs. the Original Board
This procedure covers only the modern GottFA80_Plus and GodRi80 replacement boards sold on Pinballs.Store. These boards use modern surface-mount (SMD) components — the AP2310 MOSFET and the 74HC175D decoder — which desolder with a hot-air rework station.
GottFA80_Plus / GodRi80 (this procedure ✅)
- SMD (surface-mount) components
- MOSFET: AP2310 (SOT-23 package)
- Decoder: 74HC175D (SOIC package)
- Tool required: hot-air rework station
- Rule of thumb: MOSFET Q = Lamp L + 1
Original Gottlieb System 80 driver board (different procedure ❌)
- Through-hole components
- Different transistors depending on the model (SCR, BJT...)
- Decoder in a classic DIP package
- Tool required: soldering iron + desoldering pump
- Different schematic and part correspondences
💡 If you still have the original Gottlieb board, check the documentation specific to your model, or consider replacing it with a GottFA80_Plus for modern, reliable components.
1. Tools You'll Need (GottFA80_Plus / GodRi80)
Before starting your GottFA80_Plus or GodRi80 repair, gather these tools. Everything costs under $50 total and will come in handy for future repairs.
| Tool / Part | Exact Reference |
|---|---|
| Replacement MOSFET | AP2310 |
| Decoder IC | 74HC175D |
| Soldering flux | — |
| Hot-air rework station | — |
| GottFA80_Plus board | Full replacement |
| Multimeter | ~$10–$20 |
| Ceramic tweezers | ~$5–$10 |
| Isopropyl alcohol | ~$3–$5 |
| Old toothbrush | Free |
💡 The AP2310 MOSFET and 74HC175D decoder are typically much cheaper on AliExpress if you can wait for shipping.
2. Understanding the Fault: Why Does a Lamp Stay On?
On the GottFA80_Plus and GodRi80, each lamp is controlled by an AP2310 MOSFET in an SMD package. This transistor acts as an electronic switch. When it fails due to a short circuit, it gets stuck "on" — exactly like a switch you can no longer turn off. The result: the lamp stays lit indefinitely.
The 3 Symptoms of a Blown MOSFET
- A lamp lit continuously as soon as it's powered on
- A lamp glowing faintly and continuously (partial short)
- Several lamps in a group lit at once, or the whole group dark → the 74HC175D decoder is also damaged
⚠️ The most common cause is a short circuit under the playfield. The fault is localized and 100% repairable without replacing the entire board.
3. Identifying the Faulty MOSFET on the GottFA80_Plus
Check your machine's technical documentation to identify the lamp-to-component mapping. On the GottFA80_Plus and GodRi80, a simple rule applies:
📌 On GottFA80_Plus / GodRi80:
MOSFET number = lamp number + 1
Example: Lamp L29 → MOSFET Q30
💡 If every lamp in a group stays lit, replace both the AP2310 MOSFET and the 74HC175D decoder.
4. Desoldering the Failed Component with a Hot-Air Station
The components on the GottFA80_Plus and GodRi80 are SMD — they must be desoldered with a hot-air rework station. Original Gottlieb boards use through-hole components that require a standard soldering iron instead.
Recommended settings:
| Parameter | Recommended Value |
|---|---|
| Temperature | 300°C (572°F) |
| Airflow | Level 6 or 50% |
| Nozzle-to-component distance | 1.5–2 in (4–5 cm) |
Desoldering Technique
- Apply a small drop of flux to the component
- Hold the nozzle 1.5–2 in (4–5 cm) from the component
- Move in slow, even circles — heat the PCB, not the component directly
- Gently nudge with ceramic tweezers — the component slides freely once the solder melts
- Remove the component and let it cool for 2–3 minutes
❌ Never force it! If there's resistance, the solder hasn't melted yet. Forcing it tears the pads off the PCB — an unrepairable mistake.
5. Cleaning and Prepping the PCB
A clean PCB is the key to a successful resolder. Apply a few drops of isopropyl alcohol to the pads and gently scrub with an old toothbrush. Repeat as needed.
ℹ️ Isopropyl alcohol isn't conductive. Any trace left on the PCB won't cause a short circuit.
6. Soldering the New AP2310 MOSFET
Positioning and soldering the new AP2310 component on the GottFA80_Plus or GodRi80:
- Apply a tiny drop of fresh flux to the clean pads
- Place the AP2310 MOSFET in position — check orientation: two pins on one side and only one on the other
- Station at 300°C (572°F), airflow level 6
- Move in circles 1.5–2 in (3–4 cm) around the component
- Once the solder melts, the component settles slightly and self-centers
✅ Sign of a good solder joint: the solder is shiny and even, and the component sits flat.
7. Checking the Solder Joint with a Multimeter
Set your multimeter to continuity mode (diode or beeper symbol):
| Test | Probes | Expected Result |
|---|---|---|
| Drain-source connection | Left pad ↔ right pad | Beep = connected ✅ |
| Pad ↔ component (each pin) | Probe on pad, probe on pin | Beep = soldered ✅ |
| Short-circuit check | Between unconnected pins | Silence ✅ |
⚠️ Rest the probe gently without pressing on the component — pressing can create a false mechanical connection.
8. Testing the Machine After the Repair
Reassemble the playfield, insert the GottFA80_Plus or GodRi80 board, and power on the machine. The repaired lamp should turn off normally at startup. Run the lamp test menu to check everything.
🎉 If everything works: congratulations, you just repaired your board for under $5 in parts!
FAQ
Does this procedure work on the original Gottlieb driver board?
No. This procedure applies only to Pinballs.Store's GottFA80_Plus and GodRi80 boards. Original Gottlieb System 80 driver boards use different through-hole components, with a standard soldering iron and a different procedure.
What's the difference between the GottFA80_Plus and the GodRi80?
Both are modern replacement boards for the Gottlieb System 80. They use the same SMD components (AP2310, 74HC175D) and the same repair procedure. The GottFA80_Plus additionally covers the full System 80A/B range.
Can I repair it without a hot-air station?
Not for the GottFA80_Plus / GodRi80 — the AP2310 and 74HC175D are SMD components and can't be properly desoldered with a standard soldering iron. A $25–$35 hot-air station is essential.
MOSFET or decoder — how do I know which one?
A single lamp stuck on → AP2310 MOSFET only. Several lamps in a group lit at once → both the AP2310 MOSFET and the 74HC175D decoder.
Can I just replace the whole board instead of repairing it?
Yes, and it's recommended on very old machines. The GottFA80_Plus from Pinballs.Store fully replaces the original board and makes the machine significantly more reliable.
Conclusion: Repairing a GottFA80_Plus Isn't Intimidating
Repairing a GottFA80_Plus or GodRi80 driver board on a Gottlieb System 80 isn't as scary as it sounds. With a hot-air station, a multimeter, flux, and the AP2310/74HC175D components, you can diagnose and fix a fault in under an hour for less than $5. Just remember: this procedure doesn't apply to original Gottlieb driver boards.
- ⚠️ This procedure is ONLY valid for GottFA80_Plus and GodRi80 boards
- Always check the documentation before touching anything
- Never force a desoldering job — if there's resistance, keep heating
- Always test with a multimeter before reassembling the board
More repair tutorials are coming soon. Questions? Contact us or visit Pinballs.Store to see all our boards and parts.
