R type 2, quiet sound

[thomj]

I've been loaned an original r type 2 pcb. The sound on it works but is quiet. The volume pot doesn't make it louder or quieter at all, but if you turn it all the way down it'll suddenly mute it.

I thought perhaps it may be a pot problem but there are some empty component spots, wanted to check nothing was missing



Anyone know if any of those spots should be filled?

[SuperDeadite]

Don't know about R-Type 2, but my Kengo board (same pcb) looks identical to your R2. And the sound pot functions properly on mine.

[thomj]

I guess I should try and meter the pot then if thee don't look to be any missing bits. Thanks

[VectorGlow]

First check that the boardset is getting +12 volts DC, as well as -5 volts DC.

Then check the resistance of the pot - turn the boardset off, flip it over and crank the pot all one way - check the resistance. Crank it all the other way - check resistance again. I can't remember off the top of my head what resistance value the pot is - it will be a few K though.

If that's okay then I'd personally check the electrolytic caps (the green caps) and if they check out then check the sound going INTO the amp (this can be checked with an oscilloscope or a crystal earpiece).

Please report back here with your findings.

[thomj]

The volume pot's dodgy. Thanks for the help.

Deadite, could you please see what the value of your volume pot is?

[SuperDeadite]

Sure, if you can explain what you mean exactly..

[VectorGlow]

He means the resistance value of the pot.

Afraid I don't have one here to check.

[VectorGlow]

He means the resistance value of the pot.

Afraid I don't have one here to check.

*sarcasm flying over head sound*

No sarcasm intended or implied - just saying. Don't get offended.

[VectorGlow]

Oh, doh is me! Sorry, rushing around like a blue-arsed fly here and the brain is working on low power.

[thomj]

VG descried how to meter the pot earlier in the thread Use a multimeter set to resistance, k ohms

Then check the resistance of the pot - turn the boardset off, flip it over and crank the pot all one way - check the resistance. Crank it all the other way - check resistance again. I can't remember off the top of my head what resistance value the pot is - it will be a few K though.

If you can tell me the numbers you get I can buy a pot with the same values

[SuperDeadite]

Ah, sadly I currently lack a proper meter to do this with. Sorry...

[thomj]

OK man. I'll find someone else. But you really NEED to get a multimeter. Doesn't need to be fancy. Mine was only £4 or something.

[Jamtex]

Kernow : I wonder if there is any voltage going across these wires *Sticks wires to tongue, wakes up 2 hours later* Yep that was definately mains voltage.