Stingray (Stern, 1977) : pannes et carte de remplacement (MPU Stern M-100)
Is your Stern Stingray no longer starting, showing dead displays or runaway coils? These symptoms are typical of Stern microprocessor pinballs (M-100 MPU), whose original board is now over 40 years old and almost always suffers from a leaking battery. A battery-free replacement board gives your machine a second life.
About the Stingray (Stern, 1977)
Released in 1977, Stingray is one of Stern's very first solid-state pinballs (a chime machine). It uses the Stern M-100 MPU board, distinct from the Bally boards.
- Manufacturer: Stern
- Year: 1977
- Electronic system: Stern M-100 MPU
- Type: solid-state pinball, chimes
- Theme: abstract / op art
Common faults (Stern M-100)
On Stern M-100 microprocessor machines (1977-1979), the recurring faults come from ageing: a battery leaking on the MPU (corroded traces, the number-one cause of dead boards), tired logic circuits (RAM, PIA, no boot possible), oxidised or burnt MPU/power connectors (look for heat marks), displays with missing segments, and the power/driver board (rectifier, fuses, coil transistors) to overhaul.
Stingray-specific issues (from forums)
- Battery leaked on the MPU: corroded traces, to be dealt with first.
- Does not start: RAM or logic circuits of the M-100 MPU to check.
- Dead or partial displays: display power and MPU to check.
- Runaway or dead coils: driver board (transistors, fuses) to overhaul.
- Oxidised or burnt connectors: to be replaced to make the machine reliable.
- Silent chimes: chime coils and their drivers to check.
Replacement board for the Stingray (Stern M-100)
Important: the Stingray uses a Stern M-100 MPU board, different from the Bally board. The most suitable replacement board is determined case by case: contact us with the references of your boards, and we will tell you the solution (battery-free, free support).
📚 Further reading: Guide: which MPU board for a Bally / Stern (1977-1985)?
FAQ — Stingray Stern
Which replacement board for my Stingray?
The Stingray uses a Stern M-100 MPU; contact us with the references of your boards for the right solution (battery-free).
My Stingray no longer starts.
First check the battery and corrosion on the MPU: it is the number-one cause of dead boards.
Coils run away or do not respond.
On the power side, the driver board is at fault (transistors, fuses); contact us for the diagnosis.
Should I keep the original battery?
No: a battery-free board removes the number-one cause of corrosion.
How long does it take to install a replacement board?
Installation is Plug & Play: a few minutes, no soldering, with tutorials and free support.
Does a battery-free board keep the settings and high scores?
Yes. Modern replacement boards use non-volatile memory: no more battery, no more corrosion, and the settings are kept when powered off.
Step-by-step diagnosis
- Power off, visual inspection: look for any battery or corrosion marks on the MPU of your Stingray, especially around U10/U11; remove the battery if it is still present.
- Power supply: measure the 5 V and check that it reaches the MPU; check the bridge rectifier and the power-supply fuses.
- Grounds: redo the grounds between the MPU, the power/driver board and the display.
- Connectors: re-pin the oxidised Molex connectors, especially the MPU↔power link.
- Displays: never plug or unplug a display while powered on; test with a known-good display.
- Final test: check start-up, credits, coils and displays; the BallyFA replaces the MPU, battery-free. If needed, contact the free support.
