Need Help with Triac and Phase Control Unit Not Working

Thread Starter

bwilliams60

Joined Nov 18, 2012
1,350
Need a little help from the forum. I have a router (woodworking) that has blown a tantalum smd capacitor on the board and need to identify it if possible. Here is what I have for markings
EPCOS
C155
R9 06
I believe it is 1,500,000 pF. Is that correct? Is that the same as 1.5 uF?
If good so far, what voltage am I looking for. I'm guessing in the range of 16 V?

Let me know if you can. Thank you
 

b1u3sf4n09

Joined May 23, 2014
113
Do you have a picture of the cap or the board? Epcos no longer makes tantalum capacitors; that group was bought by Kemet:

http://kemet.mediaroom.com/2005-12-12-KEMET-Agrees-to-Acquire-EPCOS-Tantalum-Capacitor-Business

I only mention this because finding old Epcos datasheets is proving a little difficult. You are correct in your assessment of the capacitance. The value I have memorized is 104, which corresponds to the most common capacitance: 0.1μF (10pf * 10^4)

My current guess to the rest: R9 - 9V rated voltage, 06 - year code 2006
 
Last edited:

b1u3sf4n09

Joined May 23, 2014
113
If you want a replacement and don't want to worry about overvoltage, get the highest rated cap in that same footprint. This would be the simplest and fastest solution.

If you have a schematic, we can take a crack at finding the appropriate rating for the capacitor.
 

Thread Starter

bwilliams60

Joined Nov 18, 2012
1,350
I am not going to be able to find a 1.5uF tantalum SMD capacitor in my area quickly. Is there something I can substitute for this cap? I have room for a regular mount cap. Any suggestions. Ceramic or polyester film?
 

Thread Starter

bwilliams60

Joined Nov 18, 2012
1,350
The IC is a U211B. Other numbers on it are T 327 and 46304-12. The TRIAC is a BTA24 600BW. Are these the parts you are referring to? The potentiometers are 47K ohms.
 

shortbus

Joined Sep 30, 2009
8,043
I am not going to be able to find a 1.5uF tantalum SMD capacitor in my area quickly. Is there something I can substitute for this cap? I have room for a regular mount cap. Any suggestions. Ceramic or polyester film?
Aren't tantalum caps polarized? A ceramic or film cap probably wouldn't work. Don't you have any "junk" electronics in the shop? Maybe scrounge a cap from a junk item?
 

BobTPH

Joined Jun 5, 2013
2,579
Aren't tantalum caps polarized? A ceramic or film cap probably wouldn't work. Don't you have any "junk" electronics in the shop? Maybe scrounge a cap from a junk item?
There may be other reasons why a ceramic or film capacitor would not work, but not because it is non-polarized. A polarized capacitor can be replaced with a non-polarized capacitor (but not the other way around.)

Bob
 

Thread Starter

bwilliams60

Joined Nov 18, 2012
1,350
Good point shortbus. Didn't think about polarity when I should have. Regardless, I have looked through my junk and can't find any 1.5 uF caps anywhere. Will have to keep digging. Thanks for your help
 

ian field

Joined Oct 27, 2012
6,539
Aren't tantalum caps polarized? A ceramic or film cap probably wouldn't work. Don't you have any "junk" electronics in the shop? Maybe scrounge a cap from a junk item?
Why wouldn't a non polarised cap work in place of an electrolytic?!

There have been very many occasions that I've replaced dried out small electrolytics with either multilayer ceramic chip of mylar film.

The only issue I've encountered is finding non-electrolytic types compact enough to fit the available space.
 

shortbus

Joined Sep 30, 2009
8,043
I guess now that tant caps have lowered in price it doesn't make a difference. Just can't see a manufacturer using a tant where a ceramic would do the job.
 

ian field

Joined Oct 27, 2012
6,539
I guess now that tant caps have lowered in price it doesn't make a difference. Just can't see a manufacturer using a tant where a ceramic would do the job.
One caution - tantalum caps are probably the least tolerant of reverse polarity.

When I used to repair PC monitors, I frequently encountered one popular model that sometimes had a tant bead fitted the wrong way round. The circuit only handled small signal levels, but every single reversed tant had gone leaky.

It was only a few uF, so I always replaced it with a foil type.
 
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