My Ambika was smoking!

It happed while I was using a d-link 9v AC power supply on my newly built Ambika:
I saw some white smoke came out from the 7908 chip. The cap beside it swelled and it seems going to explode. I’m very bad at circuit especially with AC power so I don’t really know what’s exactly happened.

my PSU spec: input 220v~50Hz
output 9v~1000mA
The voltage of my power supply while I directly test it is about 11.5v.

Everything seems OK while I test it on a 9vDC adapter(without any sound anyway).

Really hopping someone could help me, I’m really not want to hurt this piece of beauty again.

Don’t test it with a DC adaptor, you risk damaging it.

I think you need to replace the capacitors in the PSU section at the least. Are you capacitors the correct voltage rating? the wrong value can wear out too soon. Also cheap capacitors aren’t always very good.

Probably wrong polarity of one of the capacitors.

Unless it uses SMR voicecards, there’s also a good chance you have destroyed the V2164 chips on the voicecards if you connected it to a DC supply. Why did you do that?

thanks for you guys’ fast reply. Plugged in a DC supply was an mistake. I will never do that again. Maybe I used 16V voltage rate capacitors in power supply circuit caused the problem. I’ve already change all of them.

One thing I’m not sure about is the voltage reading I got from my 9VAC PSU. Is it normal that I got 11.5v from that?

The measurements you get when the power supply is completely unloaded are bogus.

HOHOHO!
it is back to alive now! Thannnnnnnnks again guys!
I thought I would ruin it, (/ω\).

Hi,

I got confused with all the power supplies of all my synth and plugged a 12v 1200mA output supply to the ambika. It was plugged for about 10 min then unplugged and plugged the correct one. Would this have broken my ambika? Some of the notes on the keyboard are not triggered. Not sure if I blew up something? it was never smoke or smell of burn. Any help is greatly appreciated :slight_smile:

thanks!

I assume your PSU was DC and not AC (that’s the problem right?)

Which voicecard are installed in your Ambika? If they contain 2164 chips (SVF, 4P), some of those chips might have been damaged since they do not tolerate the disappearance of their negative supply.

If some notes are missing, it’s likely that these are the notes assigned to a damaged voicecard. Check the voicecard activity LED to identify which voicecard is active when you play a “silent” note – that’ll be the voicecard(s) that need to be repaired.

Thanks,

Yes the PSU was DC 12V. :frowning:

i noticed 3 voicecards are not showing the leds so i deactivated them in the voice assign settings.

I also noticed another problem. Not sure if this made it happen, but when I use an external sequencer and I click play (from he beging) to play the sequence, the synth settings or presets are restored to the default preset in the SD card “Junon” like if i had reseted the synth. Is this normal?

Would you know anyone that could help me to fix this? I bought it on Reverb and im bad at soldering.

This is actually a very easy fix, if you open it up you can look for the LEDs on the cards take note of which cards are not playing sound, souce some cool audio 2164 chips (pretty easy because they’re in production), and pull the old broken ones out and put the new ones in when you get them in the mail. They’re on the boards in sockets jic something like this happens.

Cool, so I just need to order 3 of these? I just dont know which of the two…

V2164M is SOIC 16 – Suitable for SMD/Surface Mount

OR

V2164D is DIL 16 – Suitable for through hole

https://www.thonk.co.uk/shop/coolaudio-v2164-all/

then just pull out the old ones and add these new ones and that will fix the issue? Would anything else have had burnt out with the dc psu?

Also how do i fix he problem of ambika going back to default presets when pressing play in my sequencer? It seems that when i recives midi signal it reset to its default settings/presset, so the patch i had designed is gone…

Thanks

Check that your sequencer is not sending a program change!

You need the DIL package. afaik thats the only possible failure point. but @pichenettes knows better :stuck_out_tongue:

Thanks @pichenettes it was the program send. :slight_smile:

@psynautic I just checked my Voicecards and the problem is that they don’t seem to have the V2164D chip or maybe is marked with different number?

The voice cards I have are in this photo:

6 Polivolks Voice Cards.

The are this ones:

Also if the issue is that chip that may habe burnt out, do i need to install the frimware again? Or it will get fixed by just changing whatever chip i need to change?
Thanks! :slight_smile: