S+ mpu no sound

[Coinopcollector]

Turns out i have a faulty mainboard, a search trough the forums learns that most of the times a swap is the most easiest way offcourse.

Is there anyone that can give me a idea what's the most common faulty part if there's no sound coming from the mpu, what parts turn to be faulty most of the time: the potmeter....

Any help is welcome, it saves time measuring out parts ofcourse,  i prefer to repair the mpu instead of trowing it away, the rest does work fine so in case i can't repair it it will be a testboard for other machines.

[coorslight115]

Turns out i have a faulty mainboard, a search trough the forums learns that most of the times a swap is the most easiest way offcourse.

Is there anyone that can give me a idea what's the most common faulty part if there's no sound coming from the mpu, what parts turn to be faulty most of the time: the potmeter....

Any help is welcome, it saves time measuring out parts ofcourse,  i prefer to repair the mpu instead of trowing it away, the rest does work fine so in case i can't repair it it will be a testboard for other machines.

have you swapped the MPU so as to narrow it down to the MPU and not any other componet?

[stayouttadabunker]

Put a multi-meter on a couple of poles of the sound potentiometer blue knob and check the resistance.
If your resistance is solid and doesn't change on the multimeter- it's probably burned out.
I'd replace it with another one.

On one machine, I removed the potentiometer and soldered header there instead.
I then made a small harness with a couple of wires and ran it out to a unused door lock hole
and installed a small rotating switch.
Now I control the volume whenever I want from outside of the machine.

[poppo]

Some questions.

1. Did it ever work?
2. Are reel sounds turned on with the self test, or dip switches (depending on SP chip).
3 With the MPU in the machine, turn the blue pot all the way CCW and see what happens.

[Coinopcollector]

Hi,
yes i did check the dipswitches and i should have sound when reels turn and stop.
Look there's no sound at all, no coindrop nothing,i can turn the pot as much as i want nothing.
I swapped the board and everything OK, so there's why i don't have to search any further then the board itself.
When i swapped the board there's nothing more left then the speakers and wiring so they are fine.

Before i start a message on the board i want to be sure i did not skip any items from former messages posted on the board.
I only saw there's never being mentioned about how to repair the boards but hey offcourse the sponsors they have to live also i know.

Sorry for the sponsors but these day's where all so used in swapping items when they are broken, we end up learning nothing from the electronics anymore.
I prefer to have items fixed by a solderin gun if at least it is possible to do so, i know sometimes litlle components can't be soldered anymore and over here in Europe they started
using LEAD FREE solder now in newer boards like stern pinballs etc...that will be another thing when we have to repair boards....

I will check the potmeter first, thanks.

[knagl]

I will check the potmeter first, thanks.

For sure, that's where I'd start since you've narrowed it down to the MPU board (since swapping in a new one resolved the issue).  I've seen a ton of machines where the pots have gone bad resulting in bad audio or lack of adjustment.

Welcome to the site -- glad to have you here. 

[stayouttadabunker]

If your potentiometer knob checks out okay, consider swapping the AYxxx sound eprom with a
known good one to see if you get better sound results.
Maybe it's corrupted?