The Multisound module is used in the system1 games Totem and later and moreover in most of the european system80 games (cheap versions) including the System80A game Devils Dare. The layout is quite simple - I will explain certain circuits before I speak about possible defects. I guess, most of the owners want to start repairing and cannot wait do begin...

C) voltages and grounding problems:

Compared to the sys80 sound board, the sys1 version has its own +5V voltage regulation. If the big voltage regulator, a MA 7805 TO-3 has less than 4,95V, change it against a new one.

Four diodes 1N4007, a capacitor (47µF system 1, 470µF system80), another diode, type Zener (-12V) and a resistor (430R sys1, 470R sys80, works also for all Sys1 games) are responsible for a constant -12V voltage. This voltage is needed for the DAC1408. If you do not have -12V, change all parts listed above. They are pretty cheap as well..

This module makes no exeption, when we talk about bad grounding of Gottlieb games. If the connector is corroded or just looks bad in any way, change it. Also the connector pads on the module might cause problems. Use fine sand paper (1000) and clean the pads carefully!!! A bad grounding could destroy your 6503 CPU and last but not least the 6530.

D) reset circuit and clock:

That is indeed quite easy to check: No 5V +/- 10% at Pin28 / 6503 means a defect NE555. Change the 7404, if you do not messure XXX volts at the clock entry of the 6503.

E) amplifier and digital/analog converter (DAC)

The LM380 amplifier (14Pin version) is usually OK. If you do not hear a sound, touch the 47K resistor next to the IC. If it is warm, the LM380 is not the reason. If the DAC1408 is defect, the sounds are either to fast during oparation or the bias is out of range.

F) 7404 - 2nd IC:

If just one sound, for example the 100 points bell, is dissappeared, change the 7404. Be careful, there are two 7404 on this board. Please do not solder without practise or your board might look like the one on the left (see 7404).

G, H ) 6503, 6530, SND Prom Typ Harris 7643.

If the sound prom is defect, you can hear a really annoying, constant sound out of the speaker. Touch the Prom with one of your fingers: If the Prom is incredible hot or pretty cold, you have to buy a new Prom. Always use a heat sink to prevent the Prom from overheating. If you can hear a weak tone and you do not have the usual woogwoogwooohwooh sound, replace the 6503. Same for a test switch, that is not working. If you hear some bizarre sounds or there are no other defect components, the 6530 needs replacement. Unfortunately, the 6530 is one of the most common defects...

X) where can I get replacement ICs?:

Today most of the ICs are really hard to find.. However we still have all parts in stock, so that you do not need to worry. You can order the 7404, the LM380, the 6503, the sound rom as well as the 6530 (use MIOT-Adapter) from this website. In general check section "Petra" and for both sound prom and 6530 section "Sandra".

© 2005, 2007 Nicole.

Photos © 2005 Xplorer, Nicole.

please do not ask questions, that are already answered in the text :)