Aleph 5 startup

[Jarno]

Hello all,

I almost finished my soldering activities for one channel of Aleph 5. I would like to test this channel, but I'm wondering if someone could enlighten me on the startup sequence. Do I damage the mainboard if I start it up without output mosfets?

What I would like to do is:
First, connect the mainboard and check voltages.
Then, connect output boards and check for DC offset on the output.

Any more ideas on starting up Alephs?

Regards,

Jarno.

[george a]

Hi Jarno

I started up my A5 without the output mosfets, you can't measure all required voltages. Mine was not damaged by leaving them out.
Try a variac to slowly apply voltage to Power supply if possble, I used a light bulb in series...
quadruple check correct orientation of the ztx450/mpsa etc transistors.


refer my postings at aleph 5 help...please

cheers

[Jarno]

Thanks George, I will go through your posts in the thread you mentioned. Good to know I can power the thing up without the output mosfets, saves me some soldering if something is proved to be wrong. The correct orientation of the small transistors is something I am curious about, as I've reversed them because of the different pinout of the BC550's I used.
I do have a variac somewhere, I'll have to dig it up and find a way to mount a knob on it (apparently, the previous owner didn't bother to properly disassemble it and used a hacksaw).

Regards,

Jarno.

[SteveA]

Jarno-
I have just built an Aleph 5 and, with help from another member, found out that by shorting to ground the common point of R7, C6 and C8 one can check the voltages as per the Aleph 5 schematic .
SteveA