ALEPH P1.7 Troubleshooting

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Hi all,

I am in the process of building my Aleph P1.7 clone using veteran's board. I have just completed the power supply boards, and fired it up with a 68Vac input from the transformer. Reading between output PA and GA, the voltage rises very slowly, for about 3 minutes it started from 0V to about 7V. The voltage is still increasing, but it is supposed to be this slow? Is there anything wrong?

Thank you,
Peter
 
Formerly "jh6you". R.I.P.
Joined 2006
I have read similar questions which were referring to the board and its provider. In my opinion, the board provider should have the best quality about the board and the circuit on it. Therefore, I recommend to send the question first to the board provider.

Meanwhile, you should show us the sketch showing how far the components and wires are soldered and connected when you measured the voltages. Otherwise, most advice could come up with based on just a guesswork.


:darkside:
 
Thanks for your reply, Babowana!

I have sent a email to veteran about the problem, but in the mean time, I attached the schematic of the power supply and how I wired it for testing. All the solder joints are checked and all components are populated except R5. After about 10 minutes of waiting, the voltage climbed up to 20V, which is still far from the 60V output expected.

Thank you for your help,
Peter
 

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Formerly "jh6you". R.I.P.
Joined 2006
Yea . . . Fox is perfect ^^.

When you measure the voltages, add the temporary load of about 10-15K@0.5W resistor. I believe you will find all ok.

Nevertheless, still if you do not get the Vz of about 64V, check the values of 2.2K and 4.7K resistors once again.

Here is new sketch.


:darkside:
 

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Hi Peter

I started a thread below about weird measured values found on my Aleph p1.7 tests, and, well I think my replies score is poor. I hope you keep us informed about your progress.

Regarding the PSU, it shows no problems right from the start. I got around 62Vdc just turning it on. The mosfets get hot even with a light stamped hestsink.

All my best
 
Thank you for the help from all of you!

I soldered a 10kohm resistor between PA and GA pads, as shown in Babowana's illusration. I also connected the GA pad to the earth ground on the IEC inlet.

Now more weird things happened. The output voltage slowly rise to 0.7V and stopped increasing. The Vp is about 3.9V, as well as the Vz.

I believe that these are not the readings that I should get. So I took several photos of the board, as well as the board layout taken directly from veteran. Hope these will help.

Thank you again,
Peter

PS board layout from Veteran
 

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C2 has to be 100 nf. You use a WIMA from 220 nF. Is that possible the problem? Did you check the resistorvalues?

I made several of these PSU boards, and all of them work fine.
I tested without load, and no problems occure.

BTW, i use 1N4007 for D1-D4.

Your zeners (D6-D12) look very tiny to me.
 
wim,

From what I understand, C2 was not used in the original Passlab Aleph P1.7, but veteran put it there for better high frequency performance. The value shouldn't be critical. I had 220nF around, so I just used it.

I have double checked the resistor values, and they seem to be correct, except that the 4.7K was substituted by a 4.75k.

D1~D4 are MUR860.

I used 9.1V 0.5W Zener from vishay, namely the 1N5239. Is there any problem?

One more note, throughout the entire test time, the IRF610 stay cold with ambient temperature.

Thanks,
Peter
 
Problem Solved!!

Sorry guys, but I just found that the stupidest mistake out of all. There are 2 sets of 60V output on my transformer, and they are the same colors. I am stupid enough to take 1 lead from each set, carelessly. :bigeyes: The output voltage is yet, still 60V, but there is much current passing through.

All is well now after I correct the wiring. I am getting 59.6VDC at the output.

Thank you again for all your help, and please forgive my stupid mistake. :dead::bigeyes:
 
Fox,

I used 0.5W zeners just because they are a much better fit for the board than my other 1W zeners laying around. From what I understand, they are just a voltage reference, with very limited current passing through, correct?

Today is the day for the main board assembly!

Regard,
Peter
 
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