Brief description about post:

Some time ago I got some old computer items from a person, among the items there was a Creative Sound Blaster 16 sound card (CT2230), I was very excited because I always wanted to have a sound card for ISA slot, but the prices of retro hardware here in Brazil are extremely prohibitive.

The sound card is in good aesthetic condition, however in some places the paint that covers the tracks has come off, this is not a big problem for me, the real problem is that the card has noise in the sound and the left side is practically inaudible, this is a clear sign that this board needs a repair.

Analyzing the report of other people right here on the forum, and other people on the internet in general, the first thing that comes to mind is dealing with problems related to capacitors that may be defective or have lost part of their original characteristics due to time, considering this is an item dating back to mid 1993, we know that Creative uses some brands of capacitor that tend to fail faster than other brands, in my personal experiences Wincap brand capacitors are almost always bad, Wincap capacitors are widely used in Creative products.

This post is not intended to be a guide or anything like that, just reference material that may be useful to other people.

My intention with this post is to share with you the tests that I will carry out on each capacitor individually, the tool that I will use and the only one that I have at hand at the moment is a small multi-function device from the company Digilent called Analog Discovery 2, it has a section dedicated to impedance tests where it is possible to measure the capacitance of capacitors among other properties. I have used it before for this purpose and can confirm that it does the job.

To facilitate the visualization, I will put a table containing each group of capacitors for the same value and how many failed the test, unfortunately I could not categorize the capacitors by section of the board due to the amount of time and work required, but I believe that just knowing which ones capacitors of a certain value are more likely to fail is already a great help.

Capacitor Tests:

* Note that this device allows a massive amount of test parameters, but I configured it to be visible only the properties of capacitance (Cs) and series resistance a.k.a ESR (Sr).

Capacitor Map by BeastOfSoda:

* Although the board presented by BeastOfSoda is a CT2230, it differs slightly from mine, possibly being another revision, however the value of the capacitors is the same.

(12x) ELGEN - M - 50V - 1uF:

There are 12 units of 1uF Elgen M 50V capacitors, however, as you can see 2 of them are completely out of specification, see in the images where they correspond to Ref11 and Ref12, when observing the data it is easy to determine that on any Sound Blaster card that has Elgen brand capacitors you can start by checking them first.

(2x) SRG - 50v - 1uF:

(7x) SRG - 16V - 10uF:

(13x) WINCAP - R85SM(M) - 50V - 4.7uF:

SRG - 16V - 47uF:

WINCAP - R85G(M) - 16V - 470uF:

ELGEN - M - 16V - 100uF:

After the tests I ended up finding 2 defective capacitors
both ELGEN - 50V - 1uF, all other capacitors behaved consistently, some of them had the capacitance slightly different from each other but nothing alarming, considering that electrolytic capacitors can vary in the margin of 20% plus or minus.

That's it for today, I don't have much free time, so as soon as I replace these 2 capacitors and I can test the board I will update the post for those who are following.

I have news, the board is operational and apparently normal sound after replacing the 2 capacitors mentioned above, unfortunately I could not find capacitors of the same physical size in my electronic scraps, but this is not a problem as they are only a little bigger.

Something that caught my attention is that these capacitors that I put in place of the Chemicon brand gave much better results in the measurement than the original ones on the Elgen brand board.

To give you an idea, in the same tests they showed 2x to 3x less ESR resistance, this made me very excited to perform a total recap of the board, but due to the complexity of doing everything again it is better to leave it as it is.

For those who were curious about this last test, follow the image below, see that I tested only 5 random capacitors from the Chemicon brand, notice the huge difference in terms of ESR compared to those from the Elgen brand, although I would like to have new capacitors from Elgen to make a comparison.

My point is, I'm not criticizing the Elgen brand capacitors, but I was curious to know if capacitors with less ESR would result in a cleaner sound, perhaps justifying a complete recap.

Chemicon - VX(M) - 50V - 1uF

See from Ref13 to Ref17 where Chemicon brand capacitors have ESR as low as 4.5 ohms while original Elgen brand sound card capacitors hit almost 18.5 ohms, maybe it's due to age?

Credits:

Map of Sound Blaster 16 (CT2230) Capacitors: BeastOfSoda
Important information regarding the ideal characteristics of a capacitor: https://www.yuden.co.jp/or/product/support/faq/q007.html
Link image from Google Drive for direct viewing: https://sites.google.com/site/gdocs2direct/
Very acceptable translation from Brazilian Portuguese to English: https://translate.google.com.br/?hl=pt-BR&tab=TT
Chemicon capacitors data sheet from last test: https://www.westfloridacomponents.com/mm5/gra … 6/VX-Series.pdf

I would like to Thank the team at Digilent / NI for creating this wonderful device called Analog Discovery 2, this is a must have on your workbench.