Hairball Lola Problems
- Thread starter simsung
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Help Support GroupDIY Audio Forum:
Echo North
Well-known member
analogpro said:
You have 2 BA512's? Do they both have the printing facing the edge of the PCB like this one? They should. We had 4-5 leave here several months ago with one of the transistors reversed.
Mike
Echo North
Well-known member
It's possible you had an op-amp fail. It's either that or a bad/misplaced different part.
You can google "500 series pinout" for the voltage info.
If you're in the USA you could also send it in. We do flat rate $50 repair on those. If it's a bad op-amp, there is no charge.
Mike
You can google "500 series pinout" for the voltage info.
If you're in the USA you could also send it in. We do flat rate $50 repair on those. If it's a bad op-amp, there is no charge.
Mike
Thanks for the quick response!
Both opamps are BA512. And yes, in this case, both the PNP transistors are oriented properly (markings facing the outside edge of the PCB)..
If you have any ideas what to check or look into, please let me know.
I have done a search for the 500 series pinouts and that was super helpful! Without that, I'm just guessing.
So the previous statement is still unfortunately true: no direct contact from + or - 15V from the edge pads to the associated pullup/down resistors.
What I find curious is that when Lola was turned on, the meter lights all turn on at first, then go out. The blue lights on the buttons seem to work as intended. The initial problem appeared to be a problem with the input signal path.
Yet now that I don't see 15V, i'm wondering if something was damaged when turned on. I don't have an immediate way of plugging this in since I don't have immediate access to phantom power or +-15V.
Again, any suggestions would be fantastic!
Both opamps are BA512. And yes, in this case, both the PNP transistors are oriented properly (markings facing the outside edge of the PCB)..
If you have any ideas what to check or look into, please let me know.
I have done a search for the 500 series pinouts and that was super helpful! Without that, I'm just guessing.
So the previous statement is still unfortunately true: no direct contact from + or - 15V from the edge pads to the associated pullup/down resistors.
What I find curious is that when Lola was turned on, the meter lights all turn on at first, then go out. The blue lights on the buttons seem to work as intended. The initial problem appeared to be a problem with the input signal path.
Yet now that I don't see 15V, i'm wondering if something was damaged when turned on. I don't have an immediate way of plugging this in since I don't have immediate access to phantom power or +-15V.
Again, any suggestions would be fantastic!
Echo North
Well-known member
analogpro said:
There are diodes immediately connected to those rails to prevent damage from a rail swap. They are D1 and D3. You'll want to measure from there.
