sammich - one of the sidchips is not making the sound **FIXED**

[legolars]

Just finished building my sammich and it seams to work fine.

But when i use polyphonic sounds one of the sids dosnt want to make any sound. =(

did i miss something? do i have to assign the voices somehow?

i tried switching place of the sids but its still the the right

one that isnt sounding so i assume they are not dead.

(6582a)

also, the heatsink is very very hot.

any thoughts?

[legolars]

problem solved. i realized it needed a stereo-cable.

but seriously, should it be that hot?

the pcb is almost to hot to touch down under.

[Wilba]

Maybe your power supply is too high rating... i.e. 12V AC 500mA is good, but 12V AC 1A may supply input to 7809 with a lot more than 12V DC.

Check voltage of pins marked with 12V on the voltage test diagram.

The heatsink is supposed to get hot, but it gets hotter if more voltage is supplied to the regulators, more than the regulators need.

Exactly where do you say the "PCB" gets hot?

[legolars]

Allright. checked my power supply. its 1,5A.

ill see if i can find another one.

it outputs 12.26 volts.

its one of those that you can adjust the voltage.

will it help if i set it to 9v?

does the synth need 12v if i use 6582a?

the pcb gets really hot say 5cm around the heatsink area.

btw, it sounds really really good! better than i had imagined!

Edited April 17, 2010 by legolars

[Wilba]

Is it 12.26V straight out of the power supply or was that measured on the PCB (i.e. at a pin marked "12V")? Did you measure this while the LCD was connected? If it's connected, this will draw current and affect the voltage. I can't find an order for your MIDIbox username, so I don't know if you're using a high-power or low-power LCD.

Setting to 9V might not work, if you had measured 12.26V going into the 9V regulator, then setting the power supply to 9V might drop it by 3V and it won't be enough for the 9V regulator, which needs 10.5V or more to operate.

You don't need 12V for 6582A... but you need enough for the 9V regulator. Also, high-power LCD backlights are powered by the input voltage, before going into the 9V regulator.

The issue is, unregulated power supplies should deliver their rated voltage when the current load is at the rated current. When the current load is smaller, the output voltage will be higher. So it's probably a good idea to find a power supply with a smaller maximum current (perhaps 500mA). However, I've run my sammichSID with a regulated 12V power supply, and I don't think the PCB gets too hot, it's definitely hot, but I've noted that the regulators are dissipating well... if they were getting too hot, then the ends of the heatsink fins would also be getting too hot, which they aren't.

[legolars]

Nope. you dont have my username. im building it for a guy called Filip in Malmö.

I measured straight from the power supply.

i found another one that was 500mA and it didnt seem to get as warm as before.

i have a low power lcd.

i think its allright.

thanks for all your feedback!

i have enjoyed building this kit very much!

and i have learned alot but it was never to hard!

great kit!

[Wilba]

Cool... I assume I can mark this thread as **FIXED** now :D