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Hello alll.
I´ve revised conscientiously the power suply LCBPS and all parts is correctly insert and tinned. With a new transformer the dac run ok some month, but finally the fuse burn and traying find the problem with another more little big fuse, the transformer burn too. I´m suffering with out my Buffalo.
Can any body help me?
Thanks a lot.
Jose
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Hello again.
My Buffalo, really is Buffalo 32S, is running again. The sound is fantastic, as always, but I´m fearful the transformer burn it again. This will happen in two or three month if is the same than other times.
I think, perhaps the problem is in the ground, and I´ll be very glad if some body help me a little.
I put simultaneously rca and xlr output (never two source at time, of course) and fixed pin 1 and 3. (I think this isn´t be problem ) and I don´t put any ground to the chasis. Can be this the cause of the problem?
Thanks a lot in advance.
Jose
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Sorry a lot for my bad English. I hope the text is understandable Edited by user Friday, September 14, 2012 6:41:47 PM(UTC)
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What type of transformer are you using and is it rated properly?
I have had 9V toroidal transformers from a particular supplier fail on two occasions with BIIs and Placids. The transformers were properly rated etc but they just failed. I also know that this type of transformer has failed in many other applications.
Also in areas where AC quality is poor, toroidal transformers sometimes fail because they cannot tolerate "flat topping" of the AC supply.
If you have a current clamp or a way to measure current draw, try and measure how much current is being drawn by the circuit.
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Hello. Thanks a lot for your reply.
Now I,m using 2x18V, 20VA from Saber transformadores (www.sabersl.com) for one LCBPS with inductors L1 and L2 and run Ok for both analog Buffalo 32S chanel, but I´d like be sure don´t burn again.
The two transforme was burned are Avel lindberg 2x15V 15VA must run well too.
I´ll revised all parts netx week, specially the capacitors, some times breaks and repairs own. Really I don´t know what to think. When the firs transfomer burn it. The Buffalo was over wood, I don´t think the problem is with the case.
Best regards
Jose
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Originally Posted by: José Humberto  Hello. Thanks a lot for your reply.
Now I,m using 2x18V, 20VA from Saber transformadores (www.sabersl.com) for one LCBPS with inductors L1 and L2 and run Ok for both analog Buffalo 32S chanel, but I´d like be sure don´t burn again.
The two transforme was burned are Avel lindberg 2x15V 15VA must run well too.
I´ll revised all parts netx week, specially the capacitors, some times breaks and repairs own. Really I don´t know what to think. When the firs transfomer burn it. The Buffalo was over wood, I don´t think the problem is with the case.
Best regards
Jose
1. The 15V transformers are 30VA. 2. Moving to a higher rated fuse because the previous one burned isn't good practice unless you know the previous fuse was too light: what was the rating? Please measure your current before you burn anything else. In this case the transformer was the weakest link, next time it could be something on your board.
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Hello guys thanks you very much for help me.
Yes, I know the risk to put higher fuse, but I hadn´t another one in that moment.
I have taken the following measures: Primary: 230V AC 34,5mA
First secundary: 18V AC 185 mA in each wire I´m not sure if 185mA is for both.
Second secundary: 18V AC 122 mA in each wire
The difference between the both secundaries can be caused by trimers
Between PSU and Buffalo + 70 mA
- 45,7 mA
I´m not sure, but i think I need 185+122=307mA
0,307x(18+18)=11,052VA must be enough 15vA for two chanels
Best regards
Jose
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Originally Posted by: José Humberto Hello guys thanks you very much for help me.
Yes, I know the risk to put higher fuse, but I hadn´t another one in that moment.
I have taken the following measures: Primary: 230V AC 34,5mA
First secundary: 18V AC 185 mA in each wire I´m not sure if 185mA is for both.
Second secundary: 18V AC 122 mA in each wire
The difference between the both secundaries can be caused by trimers
Between PSU and Buffalo + 70 mA
- 45,7 mA
I´m not sure, but i think I need 185+122=307mA
0,307x(18+18)=11,052VA must be enough 15vA for two chanels
Best regards
Jose Jose, How were the measurements done? While it was playing, or idle?
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Hello LeonvB
With transport and amplifier off. The interconect put it.
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Your primary suggests around 8W, and the secondaries are 18V x 0.185A and 18V x 0.122A, total 5.5W (approx. 70% efficiency). I agree your transformer should be fine, but I would suggest taking measurements while playing. Something is wrong if your 20VA transformer goes up in smoke with that usage.
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Thanks a lot LevonvB.
I´ll take the measurements while playing with dinamic music. I any case I´ll put a big transformers because I need this for other proyect.
Now I ask me what is the correct fuse? and if this sistem need wire up to the case and the case to the IEC´s ground. I haven´t problem with noise.
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Hi again friends.
Looking the measures. Can anybody tell me if 0,8A is a good fuse? I think is very high, but 0,5A die in act.
Despite run perfect, I´ve fear burn again.
Thank you very much.
Jose
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