Macron MPT-301 won't start

[pfrcom]

I hear a brief tick from the Primary area when I try starting it, either connected up to motherboard, HDD, ODD etc., or stand-alone connected only to HDD and jumpering PSON

AFAIK everything's original

Help with hand-holding please

[c_hegge]

Re: Macron MPT-301 won't start

sounds like it might have a shorted rectifier on the secondary bside

[Pentium4]

Re: Macron MPT-301 won't start

Check solder joints too. When you push on the top of those primary caps, do the plastic discs go down or is there pressure directly under them?

[pfrcom]

Re: Macron MPT-301 won't start

sounds like it might have a shorted rectifier on the secondary bside

bside ? - is b an abbreviation for back, or ??

Anyway, all ICs on attached pics tested with Diode Test/Continuity of Fluke 77 - with black probe on middle leg, all gave brief beep when red probe touched to either side leg

When you push on the top of those primary caps, do the plastic discs go down or is there pressure directly under them?

No, plastic discs don't go down - I assumed primary caps were like Ol' Man River, but maybe not necessarily

[pfrcom]

Re: Macron MPT-301 won't start

I've been removing all manufacturing efforts like this - doesn't show continuity on DMM, but you never know

[c_hegge]

Re: Macron MPT-301 won't start

bside ? - is b an abbreviation for back, or ??

I don't know how the b ended up there. I meant to say on the secondary side.

No, plastic discs don't go down - I assumed primary caps were like Ol' Man River, but maybe not necessarily

You might have bulging primary caps then. That could be the problem

[Pentium4]

Re: Macron MPT-301 won't start

Check the BYQ30E first, that's the +12V rectifier. Yeah, primary caps might be bad. It's pretty rare unless too much voltage goes through them.

[pfrcom]

Re: Macron MPT-301 won't start

Check the BYQ30E first, that's the +12V rectifier. Yeah, primary caps might be bad. It's pretty rare unless too much voltage goes through them.

That IC was included in "all ICs on attached pics tested with Diode Test/Continuity of Fluke 77 - with black probe on middle leg, all gave brief beep when red probe touched to either side leg"

Any other check I should be doing ?

[Pentium4]

Re: Macron MPT-301 won't start

I guess we should have asked this earlier too, are you getting voltage to the primary caps? Are you getting +5VSB?

[pfrcom]

Re: Macron MPT-301 won't start

I guess we should have asked this earlier too, are you getting voltage to the primary caps? Are you getting +5VSB?

Yes, it's getting +5VSB

Reluctant to measure voltage to primary caps - would scrap unit instead

[goodpsusearch]

Re: Macron MPT-301 won't start

This is a good psu. Definitely worth repairing.

[retiredcaps]

Re: Macron MPT-301 won't start

Reluctant to measure voltage to primary caps - would scrap unit instead

If you are getting 5V standby, in 99% of the cases, there is no need to measure voltage on the hot side. In 4+ years here, I can only recall one case there was 5V standby, but the big filter capacitor was bad because it was fluctuating in voltage.

You can, safely, measure the primary capacitors even using a cheap $5 830 multimeter (or any multimeter) if you use those clips to allow hands free measurement.

http://www.ebay.com/itm/200979921195

I usually connect the device under test to an external power bar with a rocker on/off switch. With this, I can safely be away from the primary caps and control the on/off and watch the meter reading.

The added advantage of this setup is you can see the big cap discharge on the multimeter.

Personally I dislike working on the ATX PSU form factor where everything is jam packed and crammed in there.

[pfrcom]

Re: Macron MPT-301 won't start

Maybe overlooking the forest for the trees, but other threads here about MPT-301s have shown two thick yellow wires from the power input area going to SW1 & SW2 near the primary caps

For example https://www.badcaps.net/forum/showpo...17&postcount=1
and https://www.badcaps.net/forum/showpo...37&postcount=1

But on mine there's just two stubs broken off on SW1 & SW2, and no loose wires coming from the power input area

Can anyone enlighten me please, or provide a clear pic where wires from SW1 & SW2 connect to the power input area

Is it something to do with 240V here versus 110V ?

[c_hegge]

Re: Macron MPT-301 won't start

They are probably for the voltage select switch, which is not included on your power supply

[momaka]

Re: Macron MPT-301 won't start

They are probably for the voltage select switch, which is not included on your power supply

+1

Do NOT connect these, or you will blow your primary caps!