your guide to pinball in Belgium
Thyristor module
| Sympton | Cause | Procedure |
| A) None of the lights operates | a) Connector 10 fails | Test with a voltimeter if there is alternated voltage between the two pins of connector 10 and the potentials lOVa and lOVb, The correct value is 10VAC, If the measured voltage is not correct, all the connectors between thyristor module and transformer should be checked. |
| b) 3 Amp fuses are open | Carry out a visual inspection and check fuses. Then look for shorts in lamp sockets and bulbs Replace fuses. | |
| B) The two lights corresponding to the same thyristor are always on. | a) One of the diodes is closed. | Disconnect the corresponding connector. Test with ohmeter which diode conducts in both senses. Replace that diode. |
| b) Respective thyristor remains open. | With the test point check the anode of the thyristor (central pin) , TL will be off, even with command impulse. Replace thyristor. | |
| C) A group of panel lights never get lighted. | a) Defective 3 Amp fuse. | Carry out a visual inspection. Then look for shorts in lamp sockets and bulbs. Replace defective fuses. |
| D) The two lights corresponding to the same thyristor do not turn on. | a) No command impulse preceding from MPU | See failure in MPU module |
| b) The thyristor remains open. | With the test point, check the anode of the thyristor, TL will be on even with the command impulse. Replace thyristor. | |
| E) A light never turn on | a) Fused bulb | See filament and replace bulb. |
| b) Open diode | Disconnect the connector corresponding to the thyristor and diodes. With the ohmeter, check which diode conducts in both senses. Replace diode. |
| Parts of the module | |
| Parts | Quantity |
| Thyristors BT 106 A | 23 |
| Diodes SY 124 | 46 |
| Fuses 10 K 1/4 W 10% | 23 |
| Pin COMBOLINE | 72 |
| Printed circuit thyristor ref. 510046 | 1 |