Identifying SMT caps on MS-6712

[gdement]

I have some surface mounted capacitors on an MS-6712 which I believe have gone bad. There are 4 of them on the board, and I get the following readings with an ESR meter:

ec35=0.27ohms <next to southbridge>
ec40=9.7ohms <visible in photo, near battery>
ec41=9.9ohms ""
ec46=4.3ohms <just below the photo, also near battery>

All of these have
10
16S
L33
stamped on them.
Since the readings are so inconsistent, I assume the high readings are units that have gone bad.

10 16S L33
I'm reading that as 10uF 16V, and I don't know what L33 is. "S" might be a series code. I'm using the Teapo SV datasheet as a guideline for how to read these numbers. If it's really a Teapo, then it should be SV series because of the "S". Of course Teapo is the only site I checked, so it could be anything really. They don't seem to explain their code numbers.

Am I misinterpreting this? I'd like to sanity check my specs before I draw conclusions about what parts to order. I haven't dealt with SMT caps before.

[Rainbow]

Re: Identifying SMT caps on MS-6712

Yes, they're 10uF/16V and they often go bad.

[999999999]

Re: Identifying SMT caps on MS-6712

I would get 25V 10uF SMT Tantalums. Available at any better electronics house, but also often found dirt cheap at surplus electronics sites. That is, unless those in the audio circuit are coupling the output, in which case a SMT film cap would be the best choice, and those aren't too common except at better electronics houses.

[Big Pope]

Re: Identifying SMT caps on MS-6712

Can change this position to radial type caps?

[gdement]

Re: Identifying SMT caps on MS-6712

Can change this position to radial type caps?

No, there's no through-holes in those spots on the board.

I would get 25V 10uF SMT Tantalums.

Thanks for the suggestion. If I went that route, would I still need to worry about specs like ESR and ripple current, or would just any tantalum be the same/better than what's required?

[Rainbow]

Re: Identifying SMT caps on MS-6712

No, there's no through-holes in those spots on the board.

You can use radial caps anyway. Cut the legs of the cap so they're not too long. Make a small blob of solder on one of the SMD pads and solder one leg of the cap there. Then solder the other one. Depending on space, you can put the cap angled or straight up.

[999999999]

Re: Identifying SMT caps on MS-6712

No, there's no through-holes in those spots on the board.


Thanks for the suggestion. If I went that route, would I still need to worry about specs like ESR and ripple current, or would just any tantalum be the same/better than what's required?

Any tantalum would be better specs than those pictured, but it's common practice to overshoot voltage more with a tantalum (hence the 25V suggestion) and as mentioned previuosly if they're in the audio analog output path, tantalum are going to degrade the sound.

[Rainbow]

Re: Identifying SMT caps on MS-6712

I used through-hole G-Luxons from dead PC Chips boards. They had all around 3 ohms ESR - not a single one was bad.

[gdement]

Re: Identifying SMT caps on MS-6712

Thanks for all the help everybody. Now I just need to get the old caps removed, try testing them out of circuit, and try replacing them with something else.

At least initially, I'll probably try some through-hole types from an old board and see if they fix anything.

[gdement]

Re: Identifying SMT caps on MS-6712

I pulled the smt caps off, all of them read around 8-9ohms ESR out of circuit. The strange thing is the esr reading starts lower, and gradually increases at a shallowing rate. I haven't seen that with most other caps I've checked, but I haven't had the meter very long so maybe it's not unusual.

I tried installing some gsc 10uF 16V radial caps from another board, each of them reads from 2.5-3.0 ohms esr. Thanks Rainbow for the idea of using radials - it was actually pretty easy to install them. They're easy to knock loose, but good enough for a test. I checked the esr on the solder pads after installing them, and the locations which used to be high are now in that same range (2.5-3.0). Unfortunately the board's behavior hasn't changed. Granted GSC isn't a good brand, but they measure a lot better than the old ones so this probably should have gotten it working.

The POST process goes through a few steps and then freezes before anything appears on screen. The data LED on my post card starts blinking rapidly at that point, but nothing else ever happens. I've tried different components and PSU's but nothing makes any difference. I guess I need to flash another bios chip and see if that's the problem. Unfortunately I don't have another chip at the moment and I'd rather not overwrite the existing one. But I'll eventually try that when I can.

[gdement]

Re: Identifying SMT caps on MS-6712

It was a bad flash. I flashed another chip and now it boots and runs fine. MSI sure makes it confusing to figure out which bios you should use. I nearly used a different bios from this one before deciding. It's easy to see why bad flashes would happen on this board.
Thanks for the help everybody. I'll get some smt caps to replace the radials I'm using now, since the radials seem a little too easy to knock loose.

[Rainbow]

Re: Identifying SMT caps on MS-6712

If you make the solder blobs big enough, it should be OK.

[gdement]

Re: Identifying SMT caps on MS-6712

You're right, that would probably work fine. I was just melting them into the old solder and for some reason didn't think of adding more.