Anushri Power Adapter question/ troubleshooting

Hope everybody has been having happy holidays.
I just finished putting my kit together, and am excited to turn it on, but I have yet to order it’s own power supply. So, meanwhile I wanted to just power it on and make sure it’s working, and I have this 9V 2000mA adaptor. Is this ok to use? I understand the Anushri calls for a 7.5V or 9V 200mA supply, and I’m not very knowledgeable on this subject. If it helps, the specs of the adapter are here http://www.musiciansfriend.com/accessories/roland-psb-120-power-adapter-same-as-psb-1u .
Thanks for any help on this shamefully noobish question, I’m still learning things as I go.

200mA is what the Shruthi draws, 2000mA is not what a Power Supply tries to push thru a device, so you should be fine. Please measure although the Voltage with the Shruthi attached, some WallWarts tend to deliver a higher voltage when not fully loaded. YOu should exceed 9V for to much, the regulators 7805 + 7905 might get to warm.

When I plug it in and turn it on, no LED’s come on, nothing indicates that it is even on at all. Should I look around with the multi meter to find the problem?

The filter board has two pads for a power supply switch, if you’re not using one you solder a bridge wire across instead. Have you done this?

Did you follow the voltage tests? honestly, do not cut corners, follow the assembly guide to the letter, you will save yourself a lot of pain, blown chips etc.

Oh sorry, your post is about Anushri, well I’ve not built one of those.

I don’t see two pads, nor do I see anything about it in the instructions. Perhaps you think I’m referring to a shruthi (you mentioned the filter board), but this is an Anushri. Sorry for not specifying earlier, I should’ve made it more clear than just putting it in the subforum.

edit: changed the title for you all :slight_smile:

Toggle the Power Switch :wink:

I was going to start my own thread about this but I’ll contain my question here since it is along the same lines.

I’ve pretty much finished my Anushri at this point, just need to sandwich the boards together and power it on for the first time, and while I order a power supply that will most likely be perfect for an Anushri, I want to make sure I’ve covered all my bases in terms of not royally screwing myself if I power on and have wired something incorrectly.

I read in some other threads and they advised removing a few of the ICs if you’re unsure of your power supply and want to avoid frying any chips, but my question is are there any other precautions that should be taken before attempting to power on for the first time if I know my power supply will be fine for the instrument? All of the parts are in the right places, though I’m a little skeptical about some of my solder points. I have a feeling that when I put everything together it will show no signs of life but I want to avoid making a more costly mistake.

Unfortunately I discovered I need to purchase a new multi meter, so I won’t be able to test the voltages for a few days, though I’m itching to use the Anushri ASAP.

Please don’t! If you’re skeptical about some soldering job, at least measure the obvious things like resistance between the voltage outputs of the regulators and ground while powered off. Then, go on with plugging it in without ICs and test that the voltages are as expected.

Or, be prepared for some desoldering and pain you could avoid.

Frank, I toggled the switch at first assuming that would be my initial problem, and no LED’s came on either way. As pathetic as this sounds, I can’t even be sure which position is the “on” position. And I tried running the software tuning with my headphones in after toggling the switch both times, and nothing either time. And yes, the volume is up :slight_smile:

i can’t see on the pic if the power supply is center pin positive.

I thought I remembered reading in the specs that the Anushri can take either type of plug type. For the Ambika it’s definitely center pin positive

For the Ambika its “Center pin doesn’t matter as its AC”, for all other MI Gear its Center Pin Positive which is important to DC. Read here about the difference. The Adaptor you are referencing to has excellent technical specs on this Website (none!) so i took a quick google search ( “roland psb 1 pinout”) and found all Roland PSUs have Center Pin Positive. So your PSU is right, you must have scrambled up something else… As we have no further hints other than “doesn’t work at all” please post High Res Pics of the PSU Section of the Board from both Sides, maybe we can spot something.


There are some pictures of the PSU. They are as good of quality as I am able to get, hopefully they will suffice. On a side note, the dark blue translucent case came in today, and looks fantastic!

Can you please measure the Voltages at the Pins of the 7805 and 7905 regulators?

The pics look ok, just maybe you should cut the leads a bit shorter - at this length you could have shorted something somewhere.

None of the colored points return anything on the two regulators however, I had the point “2” on the 7805 returning .25V but now that’s even stopped. Just out of curiosity, I measured the “power supply protection diode” and its pin 1 reads -9.12V and pin 2 flickers from 0.000 to -0.007, not sure if that helps any though.

Look like the polarity of your power supply is incorrect…

Well, after obtaining the proper power supply, all voltages check out, and it makes noise! I will post again after further experimentation if I come across any problems. Looks like I’m going to have to desolder the jacks for it to fit in the case as well :frowning:

you need to desolder the jacks in order to get it in the case?

yup, I probably should have waited for the case to come in before I soldered them, but I wasn’t really thinking ahead.

oh ok now i get it, the 1/8" jacks