Common problems on a Recel system III pinball machine

2.4.5. forever

2.4.5. is considered by the system as a major fault, which means that the pinball will halt, when it detects this error. 2.4.5. is caused by a "SHORT IN DRIVER". In general, this comes from a burnt coil, power transistor, or both. But sometimes, after checking all coils and transistors OK, the error 2.4.5. is still there. In such a case, the problem could come from the short/open test circuitry which resides in the mux board. Mux board switch matrix control schematic This part of the Mux board often fails. That might be the 7400 or the 7445. But it is also worth it checking the 10x2N4291. A dead component here may distort the return values of the switches on AB return lines. Then, an accidental 2.4.5 may result. Always check the 7400 and the 7445, when you get a machine that was previously in an unknown condition. Also check the flat cable on MA and make sure connections are good.
⚠Take care when replacing the 74C00. You need to install a 74C00 (difficult to find), or possibly a 74HC00. But don't use an LS00. It will not work.

Flickering display

Sometimes, after entering attract mode, the displays are flickering 44444/00000 on all 4 players. The selftest has completed successfully. But the pinball is out of control. Pressing the replay button has no effect. in 90% of cases, this is caused by at least "tilt" and "replay" switches simultaneously seen (by MPU) as closed together. The pinball then thinks it is entering "open coin door" mode and starts to display representation areas. By construction, it starts with area #4. and since replay button appears to never being released, the display alternates showing area number (4) and its content (0). And it cycles forever between these 2 screens, since no switch looks to be released.

This means that the switch matrix control circuitry on the mux board is wrong and that several lines are locked up.

Culprits are generally the same (mainly on returns A&B) as in '2.4.5. forever'

New video on WiFlip supervisor mode

A new video has just been published. It demonstrates all the possibilities of WiFlip's supervision mode applied to RECEL System 3 pinball machines. See it on :
WiFlip Supervisor

Recel System III MPU clones are available

RS3CLN is an exact replica of the original Recel system III MPU which is used in several Recel pinballs from the 70’s. Dimensions, connections, timings are totally indistinguishable. To make it work in a Recel pinball, just disconnect the 3 connectors (PC, MA, MB) from the old MPU and unmount it from the metallic backbone (unscrew the plastic spacers and the power transistors). Then, mount the RS3CLN replacement board in the same way, with the spacers, and reconnect the 3 connectors., PC, MA, MB. That’s it.

Reset on Gottlieb Sys1 CPUs

When the CPU of a Gottlieb System 1 doesn't start at all even though the clocks signals are good, it's often worth looking at the PO reset signal (TC1 pin 14) . In fact, the SCL4528BE monostable may be out of order or a surrounding component may be causing the reset duration to be too short.

Under 30ms,  a PPS4 won't start properly. However, when you're looking to replace the SCL4528BE, which you can hardly find anymore, you may come across a TC4528, an MC14528B or a CD14528B that are pin-to-pin compatible.

But beware!

In fact, the f(Rx, Cx) timings are very different from one IC to another, and so instead of generating a 300ms reset, it  creates a reset of only 30ms.

It turns out that the correct replacement for the  SCL4528BE is the CD14538BE and not the CD14528B as might have been expected.

Good news! They are available in DIL 16 from Farnell, for example.

WiFlip

We've created an Android app that lets you connect a pinball machine to your smartphone over WiFi. All you need is a PPS-4 clone.
On the smartphone, you can read the 24 configuration dip switches, keep track of the program running on the pinball machine or watch the scores and other information being displayed in real time.