Anushri power issue

I had a broken 74HC165 which shorted the +5v to the ground. I have now replaced the IC, but I’m measuring wrong power values.

I’ve now pulled out all the ICs except the LT1054 and I’m measuring +10.90V where it should be +5, and -1.25 where it should be -5.

Possibly I damaged something in the beginning when I had the broken 74HC165 in there. I can’t see nothing wrong with the joints, the soldering is the most accurate I’ve ever done. I replace the LT1054 with one from a working filter board and I’m still reading the same voltages so it’s not the IC.

What else should I check?

I have just measured the output from the inverters. At point 2 I measure +11.5V and point 3 I measure -4.7V, without the LT1054 inserted. So I guess I damaged those. Luckily I have them on stock :slight_smile: Which of the two (or both) seem to be damaged?

Turns out I had both inverters in backwards, just like me :slight_smile:

@0x80 oops …

by inverters, you mean, regulators, right?

Now the power is ok at all points, but I get no sound, and probing the circuit for sound I only hear my incoming midi signal. Points F, E, G and U are all silent, and all the leds are constantly on :frowning:

What components should I look at that might have been damaged by my +11V power level earlier? Could it be that the MCU is damaged and/or I need to reprogram it?

@MicMicMan, ehm yes I think so. The two thingies with the heatsinks attached.

Yes it’s the regulators.

Could it be that the MCU is damaged
If you really powered it with 11v, It’s very likely, unfortunately. This and the DACs (MCP4822). Possibly the 74hcxx chips. The other components should be ok, not sure about the 6n137 though (i’m a bit lazy to check the datasheets right now). Didn’t you check the voltages before you inserted all the chips?

Thanks I’ll look into them. I have a 328p as part of an Arduino board that I can take out. The 6n137 and 74hcxx I have spare. The DACs I don’t have. I’ll try to reprogram the MCU first.

No I didn’t check the power levels first. Stupid of me. With the filter boards it is mentioned in the building steps if I remember correctly. In the Anushri assembly manual it’s only mentioned in the troubleshooting part, and I just blindly followed the steps (except for flipping the regulators that is:)) After adding the midi connectors it reads “That’s it! You can insert the IC. Here’s how the finished board looks like:”

Of course I should have thought of that myself, but it wouldn’t hurt to write in the manual that it’s a good idea to actually test you voltages first…

Hurray! I finally have a working Anushri :smiley:

I replaced the 74HCxxx ICs and put in the 328p from my Arduino and flashed the firmware. All seems to be ok now! Apparently the DACs and 6n137 were still ok.

Thanks for the help. I will not make this stupid mistake ever again :slight_smile:

great news :slight_smile: