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Very low sound coming through δ1

delta1

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Re: Very low sound coming through δ1

Postby linux-works » August 20th, 2012, 5:00 pm

if you remove idc and isolate just the relay board, the pairs of pins will click the relay if you give it 5v for 1-2 secs (not longer!). if no click, reverse plus and minus and that should click. then reverse again and it should click. that confirms that relay works.

do that 8 times ;)
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Re: Very low sound coming through δ1

Postby amb » August 20th, 2012, 10:45 pm

You can measure the resistance across the relay contacts directly to see if they are working correctly (see relay datasheet for pin-outs, and δ1 schematic for reference). These are latching relays, so applying 4.5V DC pulse to the coil in one polarity will set the contacts one way, and a reverse polarity pulse will reset them the other way.
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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 8:14 am

The resistance across the coils tested ok, all 198-200 ohms. All the relays clicked in both directions. I measured for shorts across either side of the switching pins, no shorts between 4-5, 3-6 & 2-7.

I checked the resistance with the relays latched in one direction, pins 5+6\3+4 showed just over an ohm each. Pins 2+3/6+7 showed the following resistances: 620 ohms at K6, 3.89k at K5, 8.83k at K4, 10.47k at K3, 8.16k at K2, 4.94k at K1 & 2.67k at K0.

With the relays latched in the other direction pins 2+3/6+7 showed just over an ohm each. Pins 5+6\3+4 showed no connection.

I have the δ1/δ2 stack mounted on nylon standoffs at the base, could this be a grounding issue? I'd assumed they'd be connected to ground through their inputs.

I've used 22awg wire throughout, including the LCDuino power, so I can't see power to the driver boards and LCDuino being a problem.

I'm leave for 2.5 months tomorrow for work away from home so, if I can't fix it today, I'll have to wait till I get back and tackle this one again. I have to say I'm at a loss as to what could be causing this problem.
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Re: Very low sound coming through δ1

Postby linux-works » August 21st, 2012, 8:41 am

amb suggests you use metal standoffs to get a good ground.

this could be part of your problem.

one corner of the d1 has a metal ring. it goes to a ferrite and then to electrical ground.

you should not use insulated standoffs! we have always shown and told people to use metal.
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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 9:05 am

The driver section has the ferrite and is connected via a metal standoff to the enclosure. The attenuator section is on an isolated standoff. If I were to use a metal standoff for the attenuator section, would I then need to put a jumper across CGR & CGL on the attenuator section?
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Re: Very low sound coming through δ1

Postby linux-works » August 21st, 2012, 9:09 am

I recommend leaving the 'ground loop' parts on the 2 sides of the d1 empty. I've not seen a case where it was needed and those that installed an R and C there did not do any good and could have caused loops that were not useful.

did you post close-up pics, yet?
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Re: Very low sound coming through δ1

Postby amb » August 21st, 2012, 12:49 pm

astrouk1 wrote:The resistance across the coils tested ok, all 198-200 ohms. All the relays clicked in both directions. I measured for shorts across either side of the switching pins, no shorts between 4-5, 3-6 & 2-7.

I checked the resistance with the relays latched in one direction, pins 5+6\3+4 showed just over an ohm each. Pins 2+3/6+7 showed the following resistances: 620 ohms at K6, 3.89k at K5, 8.83k at K4, 10.47k at K3, 8.16k at K2, 4.94k at K1 & 2.67k at K0.

With the relays latched in the other direction pins 2+3/6+7 showed just over an ohm each. Pins 5+6\3+4 showed no connection.

Seems like the relays are all working correctly based on the above results.

I have the δ1/δ2 stack mounted on nylon standoffs at the base, could this be a grounding issue? I'd assumed they'd be connected to ground through their inputs.

Aside from the one metal standoff for ground to chassis via L1 (which is for hum elimination), the other standoffs should have no effect on this problem.

The ground loop breaker parts should also have nothing to do with this.

Now, you only have 7 relays? If so, the missing relay needs to have its Rs position jumpered with a wire! Or else the cascaded chain is broken. If you haven't already, go into the LCDuino-1 configuration menu to set this up as "7 relays", "1dB steps".
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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 1:33 pm

Embarrassingly, I didn't have the spare Rs positions jumpered (despite it being in the instructions). I've just soldered them in and am getting everything put back together. I'll report back soon.
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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 4:39 pm

It's alive! I must apologise for the silly mistake on my part and thank you for your help in getting to the bottom of it. It sounds amazing!

The Delta 1 Board (with Jumper)
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Inside the B22
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B22 & S22
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Re: Very low sound coming through δ1

Postby amb » August 21st, 2012, 4:41 pm

Cool, what kind of resistors did you use on the δ1?
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