wierd ticking/clicking sound from switching power supply

[CharlieLaub]

I contacted Abletec when I was experiencing the problems and have been in touch with a tech guy. He sent me some new spec data that includes the minimum required current draw for each input. These are:

MIN REQ. CURRENT DRAW:
V1 (+53v ): 100mA
V2 (-53v ): 100mA
V3 (+7.5v): 50mA
V4 (+5.6v): 30mA

The min current requirement for V1 and V2 can be met by connecting it to an amplifier board, even when the amp is idle. I loaded down V3 and V4 with power resistors to obtain the minimum draw - 150 ohms works perfectly. Another use for these (with a slightly higher load resistor) would be to drive a "power on" status LED.

 

[29285]

11watts minimal load for stable operation is not
what I would call a good design.
But if it works for you, everything is fine.
oops - a rhyme😛

 

[CharlieLaub]

11watts minimal load for stable operation is not
what I would call a good design.
But if it works for you, everything is fine.
oops - a rhyme😛

For $19 Dolla' it'll make you holler.
Load those low voltage supplies,
to avoid any nasty surprise.
The supply is pretty cheap,
no surprise it needs a tweak,
to make the outcome all nice.

I'm a poet and I don't even know it...

 

[Bare]

What my Pa used to say:
Buy Cheap.. Buy twice ..or if obtuse: repeatedly

 

[ZiggyFromMars]

SMPS Alesis M1

Congratulations, some switching supplies do indeed need a minimum load by design.

I'm in the same situation right now! I turned on my PSU without load after replacing MOSFETS, Diodes and what not... and the output voltages are measuring right... but i can hear a little clicking noise; sounds like it was clocked to the IC PWM... almost like an analog clock... so... i'm afraid to test the PSU with its proper load; a Bi Amped audio amplifier of an Alesis M1... how can I be sure to test it with the load without blowing up the Amp section? 😕😕😕