Ive added a heatsink to them. In the meantime ive noticed another thing... My aleph p power supply isnt grounded to chassis, do i need to ground the negative power terminal to earth? I dont have any ntc thermistors... Would a resistor work? What value?
I tried putting a 10ohm 5w resistor from negative out to chassis. The bulb glowed like crazy and it started to amoke, so i cut the power.
http://www.kk-pcb.com/a17-pwr.html
Thoughts...?
I tried putting a 10ohm 5w resistor from negative out to chassis. The bulb glowed like crazy and it started to amoke, so i cut the power.
http://www.kk-pcb.com/a17-pwr.html
Thoughts...?
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Thank you. Its very hard.. Hes only 59 (and i 30) ... I guess msuic is my escape lately, from time to time...
What else is connected to chassis? The resistor shouldn't have done anything bad - a power NTC thermistor, such as the CL-60 used commonly for this, has a cold resistance of about 10ohm.
Just power supplies. The two aleph power supplies and an auxillary unregulated 12v supply just like what is used for the pearl.
I put them directly to the chassis through 10ohms. Bulb glowwed like 100%. Didnt have the aleph boards connected though, just the power supply.
When i connect the power supply to the aleph biards the regulator 610 lows right away.. Never even heats up.
No. Veterans boards.
Im pulling my hair out. Months of trying to figure out whats wrong.
It always comes back to blowing the 610 in the powersupply as soon as the aleph boards are connected.
When i seperated rhe power supply from the aleph boards and added a connection from negative to chassis theough 10ohms, the bulb went glowing like crazy. I got thism idea from the kk-pcb schematic and thought it was an oversight that could be responsible for the problems.
... Could it be bad caps on the power rails in the aleph boards shorting the power supply?
When they were pulled there was no problem with the 610 blowing.. Swapped them with new 100v 1000uf kw nichicons and same problem came back.
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Ive realized that i haven't grounded the output of the aleph boards to the chassis.. Would this cause the repeated blowing of the irf610 when the boards are connected to the psu?
Still perplexed that there was smoke and fault light on the bulb tester when i grounded the negative output at the power supply... Maybe it needs to be done from the aleph board itself...?
Still perplexed that there was smoke and fault light on the bulb tester when i grounded the negative output at the power supply... Maybe it needs to be done from the aleph board itself...?
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0.00v +/- 0.6mv. On both power supplies. -one is currently dead, the other has just been repaired, so you can see the same effect with the 610 blown or not.. Negative to chassis
Positive to chassis is just the same.
0.00v on aux power supply zero volt line to chassis
18.6v across protection diode on working psu (just repaired)
0.79v on non working psu with blown irf610
82.3v across the first 1000uf cap after bridge
I dont understand... Now wheni attach the negatives to chassis, the bulb tester is just fine! I dont get it...l
I have a power switch between the psu and the aleph p1.7 boards which cuts the dc power to the aleph boards, so i can run it in "standby"... This switch is intended to power up or down the aleph p by opening or closing the dc power..
Could it be the inrush current from switching on the aleph boards blowing the irf610 regulator?
I ask because i managed to get the power supply fired up while connected to the aleph today.. I thought id fixed the problem by grounding the psu.. When i finally hooked it up to amp and source and powered it on a second time, i blew the 610 as soon as i powered up the aleph boards by switchinh on the dc power.
MY heatsinks are very small...
Could it be the inrush current from switching on the aleph boards blowing the irf610 regulator?
I ask because i managed to get the power supply fired up while connected to the aleph today.. I thought id fixed the problem by grounding the psu.. When i finally hooked it up to amp and source and powered it on a second time, i blew the 610 as soon as i powered up the aleph boards by switchinh on the dc power.
MY heatsinks are very small...
FormosaWest:
I also used Veteran's boards (which were excellent) and had the identical problem with one of my Aleph P 1.7 preamps. I used a two chassis design and the problem turned out to be a short hidden in the umbilical cord that connects the power supply to the preamp. I spent months needlessly staring at the power supply trying to resolve the problem. Check for a short downstream of the power supply.
Regards,
Scott
I also used Veteran's boards (which were excellent) and had the identical problem with one of my Aleph P 1.7 preamps. I used a two chassis design and the problem turned out to be a short hidden in the umbilical cord that connects the power supply to the preamp. I spent months needlessly staring at the power supply trying to resolve the problem. Check for a short downstream of the power supply.
Regards,
Scott