ALEPH P1.7 Troubleshooting

[peterpan188]

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

[Babowana]

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.

[peterpan188]

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

[Babowana]

Peter,

Could you measure Vp (Drain voltage) and Vz (gate voltage)
and inform?

[Fox]

The BOSOZ-PSU is quite similar to the Aleph-P PSU. In the BOSOZ article Nelson mentions that in order to test the PSUs separately, they should be loaded with 15k. If you don't do this the MOSFETs will blow.

Hope this helps,

Fox

[Babowana]

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.

[JC Fardo]

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

[twitchie]

Make sure all your diodes are oriented correctly, there are alot of them and sometimes things happen

[peterpan188]

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

[peterpan188]

Entire Board