sammichSID E-Switch does not work **FIXED**

[neosay]

Hey!

I was happy to get a sammichSID with batch #6 and build the device during the last week.

The sammich seems to work perfectly - the only irritating thing is that the most right buttom (E-switch)(the increase buttom)is not working.

The encoder ist working perfectly - also the decrease button but the increase does NOT - also not in any of the menues.

I resoldered the switch without any effect. The solder point of the decrease button does not touch the heatsink.

Any idea what to check?

Thanks in advance!

Neosay

[Wilba]

Check if it's the switch at fault, or the connections.

This is easiest done by shorting across the two left pins of the switch while the sammichSID is on, and watching for an effect.

You can also test if "grounding" IC2 pin 11 works (i.e. what that switch connects to - follow the track in the attached picture). You can connect pin 11 to pin 8 (ground) with a wire or even the tips of long nose pliers. Be careful not to short any other pins while you do this.

Depending on the results, you can then work out if the switch is not closing, or there's a break in the track somewhere (i.e. even shorting the pins of S12 doesn't do anything).

If the switch is the problem, I'll send you a new one, but it would make sense to check it's definitely the switch at fault.

[neosay]

Hi Wilba!

Thanks for the fast reply - not sure about the counting of PINs. I think you mean PIN12 on IC2 connected to S12, right?

The switch seems to be okay and it is connected to PIN8 (ground) and PIN12. Therefore I think no layer break.

But shorting PIN12 against PIN8 on the IC2 is not working - or the value is flipping to a very high or low value.

Shorting the PINS for S9, S10 and S11 is working correctly - same result as the swichtes do.

Also all direct connecets between switches and IC2 seems to be okay. PIN11 to S10, PIN12 to S12, PIN13 to S9, 14 to S11....

What do you think?

Thanks and Cheers

Neosay

Edited April 21, 2010 by neosay

[Wilba]

You're right, I meant pin 12.

If shorting pin 12 to pin 8 doesn't work, then it's not the switch.

Please explain what you mean by "or the value is flipping to a very high or low value"... do you mean the value of the parameter?

What is the voltage of pin 12 when the switch is unpressed? It should be 5V.

Maybe resoldering pin 12, and the adjacent pin of the resistor network, could fix something. Just a guess.

Also you should check if the resistor networks are correctly oriented with the dot in the label aligned with the dot on the PCB. As I just recently explained in another thread, the LABELS of all the resistor networks should all face the same way, towards the top of the PCB.

[neosay]

Hey Wilba!

I read the thread from TMarcel - I made the same mistake - RN3 and RN4 had the wrong orientation.

After removing RN3 and RN4 and changing the orientation (aligned to the white dot on PCB) also S12 (down switch) is now working corretly.

So I think my problem is solved now! Thanks a lot to Wilba for supporting me!!

By the way: Removing the RN3 and RN4 is not so easy - a tool to remove ICs is very helpful - you also should remove the solder with a solder pump first.

Even if the building guide is absolutly correct - the mount note for RN1 to 4 could be rephrased like "make sure that white dot on resistor and PCB are matching" (just a proposal).

Cheers

Neosay

Edited April 21, 2010 by neosay

[Wilba]

Good to hear you got it fixed!

UG GLUG GLUG :wacko: