Erratic flashing counter's dots on Recel sys3

Counter's leds

On a Recel System 3, each counter has four LEDs: 

• SELECT is at the top right of a counter to indicate that a game for this counter is in progress. 
• UP is at the bottom right of a table and indicates that this counter is in progress (ball in play). 
• 1,000,000 is located on the left of a counter. It lights up when the 1,000,000 point limit is exceeded. 
• The fourth LED is actually the control circuit for the decimal points (DP) of each 7-segment digit. They all work together for a given counter, except that if a 7-segment is off (value equal to F), then its corresponding DP will also be off. 

To manage this 1-by-1 extension of the DPs, there is the A3 circuit on the Display Board. A3 is an 8-input NAND logic gate (SN7430). After 50 years, this gate is often faulty. It is usually the cause of these strange flashes that are not synchronised with anything. 

Another typical symptom is what you can see on the illustration picture above : During the pinball startup sequence, you will observe lighten DPs on all 7-digits of all counter's including those which are off (value F) ; or vice- versa.

Replace this IC, and everything should be back to normal.

Common problems on a Recel system III pinball machine

Les leds de tableaux

Sur un Recel System 3 chaque tableau comporte "4" leds : 

•  SELECT est en haut à droite d'un tableau pour indiquer qu'une partie est en cours
• UP est en bas à droite d'un tableau et indique que c'est ce tableau qui est en cours (Ball in play)
• 1.000.000, quant à lui, se trouve à gauche d'un tableau. Elle s'allume quand on franchit la limite des 1.000.000 de points
• La 4eme led est en fait le circuit de contrôle des "decimal points" (DP) de chaque 7-segment. Ils fonctionnent tous ensemble pour un tableau donné, sauf que si un 7-segment est éteint (valeur égale à F, alors son DP correspondant sera également éteint.   

Pour gérer cette extension 1 par 1 des DP, il y a le circuit A3 sur la Display Board. A3  est une porte logique  8-input NAND (SN7430). Après 50 ans, cette porte est souvent défaillante. C'est elle qui provoque en général ces clignotements bizarres et non synchronisés avec rien.

Remplacez cet IC, et tout devrait rentrer dans l'ordre. 

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.