4 pole can't boot

After assembling my 4 pole shruthi, leds 1 5 7 are lightning, lcd is backlighing
it seems to be “sysex mode” ? what can I do ?

no change…

a detail : output level is low

are my styroflex cap in good holes ?

yay!

nice. have fun!

Yay! Glad you’re sorted - good feeling eh? :wink:

Martin

After replacing all “fake 33k and 33,2k” : it’s ok !
I got REAL resonance, I got REAL output level, And I finally can tune my osc !

I’m really suprised because I’ve tested all resistors before solder them…

To pichenette and other people : thanks for your support

Let’s go to make some noise :smiley:

@fcd72: It’s harder to miss a jumper on a header because they are parts included in the BOM and/or in your kit. There will still be stuff in the bag, like when you tore your carburator apart. Plus, if you ever want to add a volume pot, you can use a 3-pin flat connector cable to attach to the board so you can swap it out. Solder the other end to your pot. Badda bing!

I’m serious.

I un-solder a “33k” resistor and, in fact… it’s a 3,3k resistor

I’ll try to replace them all, and tell you if it change something

“they said support your local shop” grrrr

Without the Bridge beside the Audio Connector you won’t hear anything because theres no connection… so solder in the wire and everything will be fine…

What do you guys think about changing the spec for these pads and call for a male header with a shorting pin or shunt where no volume pots are used? It seems to me it would make this very common mistake harder to overlook…

I’m sorry but I’m not sure to understand you (fcd72 & titus), my english is limited

YES audio output bridge is soldered
I can ear my synth making sound. my problem is the resonance

I don’t want to solder audio input brdge because I know I won’t use it, and I think it wouldn’t change anything

@Titus
When using a header the Jumper would be missed. Proof: 2/4 Pole Jumper on SMR-4.

10,2V everywhere

I’ve soldered output bridge
not the in, because I’ll never use it

when I tweek resonance knob, I can ear (light) variations
output level is very low (I’d to +36db gain to sound like the audio file) it could be a way ?

When you power the unit (with the “init” patch) the output level is very low?

yes
with init patch I need to add 36db gain (and it still under 0db)
it lose ~2db if resonance is at 63 (I think it’s normal)

with my other shruthi 1 (1st edition), output level is higher

This is not normal, the signal level should be close to that of a SMR4.

With your meter set in AC voltage testing mode, what is the voltage at pin 1 of IC1? And at the 4 testing points for the filter?

Have you correctly soldered the bridges near the audio in/out jacks?

Output level of the original Shruti was considerably higher than the MkII, which AFAIK was tamed a bit to match the sensitivity of audio interfaces.

We’re talking less than 10dB I believe though.

Martin

Also, 40dB change is a factor of 100, so look for a resistor in the audio chain with an incorrect multiplier (e.g. 220 ohms instead of 22k or 330 ohms instead of 33k)

Martin