Virus surgery: Re-Potting 101 (warning - many photos!)

[rtofvnt]

Hi,
I know this is a quite old post but is there a chance for high res photos of Indigo 1 main pcb where I could check capacitors polarisation?
I think I messed up with mine when I was replacing all due to LCD starting to fail.
Thanks in advance.
Cheers

[Timo]

I'll open up my Indigo v1 and take a photo for you some time tomorrow when I get spare time.

[rtofvnt]

Thanks Timo,
I will owe you a big one.
Cheers

[Timo]

Ok, I don't do this for everyone but I disassembled my Virus and desoldered the mainboard to get a good look at the caps, not only to get their polarity but the values too. Some of the caps are an arse to read as they are closely mounted and largely obscured.

Polarities are shown as red - for negative, green + for positive. Values are in yellow beside each cap.

Make sure you zoom into the photo after you display it full-size, if necessary, as it may be higher resolution than your monitor can display. It's 3264 x 1922 pixels.



Or click:

http://www.infekted.org/virus/files/...digo1-caps.jpg

Any problems/queries let me know.

[rtofvnt]

Timo - you are the absolute star with this. I do have a slightly older version - your is 4.0 - mine is 3.2, however, capacitors locations, values and polarity is the same. I just did proper check with what I currently have and unfortunately for me replacing capacitors and two 5V regulators didn't do the trick.
One thing I'm finding a little bit off is when I measure on 2575 regulator voltage between output - which is 2 pin - and the ground doesn't show me 5volts but something like 4.92 ... I know this will be a long shot, but would that be a case?
Timo - once again - thank you. Tell me where to send a case of beer
Cheers

[Timo]

Soldered and reassembled the Indigo so am unable to measure, and I don't know a great deal about regulators, but 4.92V is very close to 5V? It's only 0.08V difference.

Just looked up the tech specs of LM2575 on Google and shows it has a 4% tolerance rating, which would give it a range of ±0.2V at 5V... so you might expect anything from 4.8 to 5.2V?

[rtofvnt]

Hi Timo,
Thanks for the heads up. I checked that too.
I think there must be some other issue. My Indigo electronics seems to lose current. When I'm switching it on and measure the voltage on 5V volt regulators it stays the same but after few seconds it just dying.
There is one capacitor actually I overlooked - waiting for delivery, but my hopes slowly varnishing.
Thanks again - Matt

[Timo]

You mentioned losing current, have you tried a different PSU? Just a thought.

There'll always be a transient when you switch the Virus on/off, though, as you can probably tell when you accidently turn your Virus on after the speakers. (*thWUMP!*)

[mkaltenbach]

Hello Timo,
Excellent job documenting the disassembly of your Indigo.

Seeing the fruits of your labor was very helpful in extracting the original PUT POWERTECH AD2512A PSU from my TI keyboard after the PSU recently failed.

I've since identified and ordered the MEAN WELL GST25B12-P1J as a replacement PSU due to the GST25B12-P1J having virtually the same specifications and physical dimensions as the original AD2512A.

Thanks again the enlightening post.

[4NDRW]

ah! so detailed.

I had to pull apart my old micro-x to fix a common fault with the pitch bend. I didn't finish the full task in one day, and returning to an already opened synth, it was a challenge to decipher which sized screws went where...

I found some youtube videos and blog posts of people repairing it, I eventually figured it out,
but I longed for a post as detailed as this, for that synth, in that moment!

Good work!