Continuity on STA517B pins?

[pkcain]

Hi everyone,

I built an Amp11-HV and after checking continuity on the pins I am getting a number of them that I didn't before I populated the board. Could populating the board make more connected? I have pins 19-22 as connected and also one or two of 23-25. Now, 19-22 are grounds so I that makes some sense but 23-25 aren't so I just thought I'd ask. If someone has a working Amp11-HV and could check which pins have continuity then that would make me feel better before I hit it with 50V.

Thanks so much,
PKCain

[Jan]

Hi,

It's not clear to me what you mean. Have you downloaded the schematic?

Pin 19 = ground
Pin 20 = Ref for internal regulator
Pin 23 = 5V
Pin 21, 22, 24 = Internal VDD (5V from REF pin 20)
Pin 25 = PWRDN a pin that disables / mutes the power stage. It's connected to J4 pin 12 and pulled up to a logic high via R40. Grounding J4 pin 12 (to J4 pin 11) mutes the power stage

[pkcain]

OKay, I've got something wrong. Can I get another STA517b chip from you? I doubt I'll get the old one off without damage.

[pkcain]

Pins 19-24 are all shorted to ground. I've tried removing and adding solder and also cleaning the flux off. If I went on looks they look fine... no bridges or anything. Does anybody have any ideas? Could some of the later components be wrong so it shorts those pins? I realize this is a longshot but I'm running out of ideas. My other amps chip seems corrrect but I haven't populated the board yet so I don't know yet if it changes. Worst case I'll have to get a some chipquik and a new 517b from Farnell or something.

Thanks,
PKCain