Aleph 5 smoking

rbe43164 · 31st October 2005, 08:13 PM

have just finish the PCB of my Aleph 5 from Kristijan and I have connected them to the power supply.

When I have turned the power the resistor (1 ohm and 221 ohm on the Irfp 244 ( R64-66 and R52-54 on Nelson shematic)) side of -34 volts goes in smoking. You can see on the high resolution picture.

I have checked all soldering and the polarity of the components (ztx 450, Irfp 244, Irf 9610, condensator) and everything looks good. I have checked all the value of all resistors and everything is OK. I'm really dissapointed. Is some people have an idea of the problem ?

On the power supply I use Tr = 2x30 volts 500 VA with 4 x 47000uf on each channel. I have without charge + 41.2 * 0 * -41.2 volts.

Is it possible the voltage was to high. Do you thing I need used 2.2 uH to reduce the voltage or do you know an other possibility to go done the voltage around 34 V.

Could you help me

Netlist · 31st October 2005, 08:51 PM

Although the voltage is high I am rather suspecting one or more shorted mosfets. Certainly when the 221ohm resistor goes up in smoke. What wattage are your source resistors?

/Hugo

rbe43164 · 1st November 2005, 06:08 AM

I use a 5W 1% to drive the source and a 0.5W 1% for the gate.
I don't invert the GDS connnection on the IFP244. You can see on the picture below.

Netlist · 1st November 2005, 08:43 AM

Unless you made a wiring error or a really wrong connection, a smoking gate resistor means a broken mosfet.
A variac and/or a 60 to 100w lightbulb would be real handy to limit the current at initial startup.

/Hugo

wuffwaff · 1st November 2005, 05:13 PM

Hi,

it is very well possible that the fet was already broke when you put it in. You really have to watch for static charges. I always tough the earth connection from the mains before handling the fets. Never broke a IRFP240 but a few IRF610´s died while matching.......

William

Berry · 1st November 2005, 08:08 PM

First measure the voltage over the irf9610. If these are correct connect the irfp outut fets. The voltage is too high for the aleph5, but it will work for a while with a (big)heatsink.

rbe43164 · 4th November 2005, 05:38 PM

You can't believe that.
I'm really a poor guy (If I tell you) stupid, and what you want.
Do you know what is the problem ? Very simple, I have forgoten to put the isolate pad under the IRFP 244. Shameful.

Thank's everybody for your answer. Now everything It's Ok. I will be back in few weeks with the NEW BABY.

Duck-Twacy · 4th November 2005, 11:48 PM

Glad that you found the error. I love to see some pics from the complete amp.
Success

PS there are more Alpeh5 happily playing around with 40+ DC voltage.

Leeuwarden · 5th November 2005, 08:34 AM

Yes, mine! (only just and without load)

Berry · 5th November 2005, 04:51 PM

Running the Aleph 5 on 40V instead of 34 V , what do i have to change on the PCB ?. And how much power do i have by 4 and 8 ohm speakers ?

Berry

31st October 2005, 08:13 PM	#1
rbe43164 diyAudio Member Join Date: Nov 2004 Location: near bruxelles	Aleph 5 smoking have just finish the PCB of my Aleph 5 from Kristijan and I have connected them to the power supply. When I have turned the power the resistor (1 ohm and 221 ohm on the Irfp 244 ( R64-66 and R52-54 on Nelson shematic)) side of -34 volts goes in smoking. You can see on the high resolution picture. I have checked all soldering and the polarity of the components (ztx 450, Irfp 244, Irf 9610, condensator) and everything looks good. I have checked all the value of all resistors and everything is OK. I'm really dissapointed. Is some people have an idea of the problem ? On the power supply I use Tr = 2x30 volts 500 VA with 4 x 47000uf on each channel. I have without charge + 41.2 * 0 * -41.2 volts. Is it possible the voltage was to high. Do you thing I need used 2.2 uH to reduce the voltage or do you know an other possibility to go done the voltage around 34 V. Could you help me

1st November 2005, 05:13 PM	#5
wuffwaff diyAudio Member Join Date: Aug 2001 Location: Ingolstadt Germany	Hi, it is very well possible that the fet was already broke when you put it in. You really have to watch for static charges. I always tough the earth connection from the mains before handling the fets. Never broke a IRFP240 but a few IRF610´s died while matching....... William __________________ een ooievaar is geen konijn want zijn oren zijn te klein!

4th November 2005, 11:48 PM	#8
Duck-Twacy diyAudio Member Join Date: Oct 2002 Location: Holland, The Hague	Glad that you found the error. I love to see some pics from the complete amp. Success PS there are more Alpeh5 happily playing around with 40+ DC voltage. __________________ Is that all there is?

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31st October 2005, 08:51 PM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	Although the voltage is high I am rather suspecting one or more shorted mosfets. Certainly when the 221ohm resistor goes up in smoke. What wattage are your source resistors? /Hugo

1st November 2005, 08:43 AM	#4
Netlist diyAudio Moderator Join Date: Jan 2003	Unless you made a wiring error or a really wrong connection, a smoking gate resistor means a broken mosfet. A variac and/or a 60 to 100w lightbulb would be real handy to limit the current at initial startup. /Hugo

1st November 2005, 08:08 PM	#6
Berry diyAudio Member Join Date: Apr 2004 Location: Netherlands	First measure the voltage over the irf9610. If these are correct connect the irfp outut fets. The voltage is too high for the aleph5, but it will work for a while with a (big)heatsink.

4th November 2005, 05:38 PM	#7
rbe43164 diyAudio Member Join Date: Nov 2004 Location: near bruxelles	You can't believe that. I'm really a poor guy (If I tell you) stupid, and what you want. Do you know what is the problem ? Very simple, I have forgoten to put the isolate pad under the IRFP 244. Shameful. Thank's everybody for your answer. Now everything It's Ok. I will be back in few weeks with the NEW BABY.

5th November 2005, 08:34 AM	#9
Leeuwarden diyAudio Member Join Date: Nov 2002 Location: The Netherlands	Yes, mine! (only just and without load)

5th November 2005, 04:51 PM	#10
Berry diyAudio Member Join Date: Apr 2004 Location: Netherlands	Running the Aleph 5 on 40V instead of 34 V , what do i have to change on the PCB ?. And how much power do i have by 4 and 8 ohm speakers ? Berry

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