UcD400 Problem

[tomahack]

Thanks! 0,7 volt is with no load at output. With load, I get a few millivolt. Still nothing is coming out of the module. I'm begining to feel desperate.

 

[tomahack]

Speaker ground is also the module's chassis ground there's two connections for it but they're at the same potential.

You didn't float the module off ground or anything did you?

No. Module is connected to PS ground.

An externally hosted image should be here but it was not working when we last tested it.

 

[classd4sure]

Not floating, sensed. The speaker ground and PSU ground have zero impepdance across them, one goes to the speaker, the other to the star point.

.7Vdc is too much at the output but that is not meaningful with the output stage disabled. and no load.

There's no harm in ruling out possibilities.

 

[maxlorenz]

Tomahack:
Maybe a little drawing of your connections will help find out what's wrong. Compare it with hypex' recommended wiring diagram.

ClassD:

Normally speaker ground must be "floating".

Speaker ground is also the module's chassis ground there's two connections for it but they're at the same potential.

I meant you don't have to wire directly the speaker ground to chassis, right? Module's chassis ground is taken from the T also (?)


regards
Mauricio

 

[tomahack]

Tomahack:
Maybe a little drawing of your connections will help find out what's wrong. Compare it with hypex' recommended wiring diagram.

ClassD:



I meant you don't have to wire directly the speaker ground to chassis, right? Module's chassis ground is taken from the T also (?)


regards
Mauricio

Maxlorenz, the other monoblock is running fine so I guess the wiring is OK.The source of the problem seems to be module itself.

 

[classd4sure]

Tomahack:
Maybe a little drawing of your connections will help find out what's wrong. Compare it with hypex' recommended wiring diagram.

ClassD:



I meant you don't have to wire directly the speaker ground to chassis, right? Module's chassis ground is taken from the T also (?)


regards
Mauricio

Yeah.

Are you sure the input pins are in good contact with their vias? Since it follows the module we know it's not an external wiring fault.

 

[maxlorenz]

Oops!

Posts are crossing

I would make a direct connection from ON pin to ground

 

[tomahack]

Yeah.

Are you sure the input pins are in good contact with their vias? Since it follows the module we know it's not an external wiring fault.

Quite sure since I measure and impedance of 100K at the input caps

 

[classd4sure]

Your modules appear modified so I guess if all your connectors are solide I'd be looking around for possible solder bridges, cold joints, loose connections, maybe it's even possible you actually forgot to solder a connection and it's just sitting there..

Double check polarity of all caps you changed, if you DC coupled make sure the jumpers in place of the caps are effective,

You could always probe the supply pin of the op amp and make sure the voltage there is OK, as well as that of the lower driver supply, check solder connections all around where you soldered in case anything came loose too.

 

[tomahack]

Your modules appear modified so I guess if all your connectors are solide I'd be looking around for possible solder bridges, cold joints, loose connections, maybe it's even possible you actually forgot to solder a connection and it's just sitting there..

Double check polarity of all caps you changed, if you DC coupled make sure the jumpers in place of the caps are effective,

You could always probe the supply pin of the op amp and make sure the voltage there is OK, as well as that of the lower driver supply, check solder connections all around where you soldered in case anything came loose too.

Thanks a lot for your patience. I checked everything twice and all seems normal. Must be a protection kicking in for some reason.

 

[tomahack]

Signal is present at the output of AD8620. Where should I look after the Opamp?

 

[classd4sure]

Well, I can think of a few more things to check like auxiliar supply voltage/ bootstrap operation, turn on delay circuit...


But at this point I'd email Hypex and see if they have a better idea, even oddball problems aren't usually unique so they might be able to save you some time and agrevation. Let us know whatever it was though.