Schottky rectifier improvisation

Why changing ?

B3100 can be found at Farnell or RS for some .7? pce

SO just replace !

idem for the transistors (it dimishes the unit shipment cost).

It is the recovery time, ie frequency that is important, surely you could rob a shottky package from some SMPS somewhere?

presumably they don't ship to india or are prohibitively expensive

I'd just try one diode, accepting it might or might not work temporarily. I 'd test its Vr max first, it's regularly well above rating. But I'd not wan t to leave it in there even if it works, there's some reason the OEM paid e xtra for a shottky.

NT

That and more. Farnell and RS both have branches in India but they cater only to OEMs. I can get almost anything from AliExpress (China) and they ship quickly but transit time with free or nominal shipping charge is anywhere from 1 to 3 months.

I'm worried that it might cause further damage if the diode fails.

But I'd not want to leave it in there even if it works, there's some reason the OEM paid extra for a shottky.

The 1N5822 *is* a Schottky.

I have several different Schottky diodes besides the 1N5822 including types with much higher current ratings, but none with a Vr rating more than 45V. And that includes those from SMPSes.

I stock one 3A ultra-fast PN type but it's the 1000V version (UF5408) and has a high forward drop. I also have some fast-recovery types but they're probably too slow.

Do you have a schematic available you can post? Is the "standby supply" a linear PSU? Could be that they just used the B3100 because that's what they had on hand in quantity and the faster recovery time is immaterial

te.

n.

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y. I'd test its Vr max first, it's regularly well above rating.

hence test its V_r first. It's often way higher than the specs claim. Just use diode, capacitor & resistor from the mains to apply a tiny reverse curr ent, measuring the voltage at which it conducts. Following safe practice et c.

my bad. It might be perfect for the job then, depending on V_r.

NT

NT

NO !

I am a lambda person.

And I am a customer of both RS and Farnell.

And yes, they do ship in India (just a question of delivery delay).

Maybe visit India some time

NT

No schematic. I downloaded the service manual but they omitted the power supply - deliberately it seems. They note in one place that the PSU is not serviceable and must be replaced as a unit.

The standby supply is definitely a switching type. It is only one section of the whole power supply system which is on one large single-sided board.

Since you want an answer about function before ordering parts, Can you supply an external 15V to the driven circuit? Then put the best solution for the diode replacement you come up with and verify the switcher is functioning using an external load. A little convoluted but reasonable to save a month wait for a second order of parts. Mikek