This is out of a 600 watt computer power supply (CoolMax ZX600) and I don't know how to identify it without markings or a schematic and hoping someone can help. The PCB spot for this is labeled BD1 and the main transformer is a ERL-39 (17RL3927). I've looked on the sides and the back and no markings except the "Sep" and "H1" on the front as shown in image. Thanks in advance for any help at all, trying to replace. Need to add that this does show AC on the PCB for two inner pins.

Also the dimensions are Width = 22mm Height = 18.5mm Thickness = 3.2 - 3.3mm

bridge rectifier

  • \$\begingroup\$ Are you trying to replace it? Or are you trying to determine how to recycle it into another project? \$\endgroup\$
    – Hearth
    Mar 27, 2019 at 3:18
  • \$\begingroup\$ @Hearth Replace. \$\endgroup\$
    – Pat
    Mar 27, 2019 at 5:25
  • \$\begingroup\$ It appears to be mounted upside down. What's on the other side? \$\endgroup\$ Mar 27, 2019 at 5:51
  • \$\begingroup\$ @ Bruce Abbott It's blank on the other side. No indents or anything, smooth. \$\endgroup\$
    – Pat
    Mar 27, 2019 at 6:31
  • 1
    \$\begingroup\$ Without markings of any kind, I'd first trace out schematic details to see how it is actually used. Then, if it really seems to be a bridge rectifier, I'd look for similar devices of similar packaging (or larger.) You should be able to work out the reverse voltage requirements (PIV or PRV) from what you determine looking over how it is used in the circuit. \$\endgroup\$
    – jonk
    Mar 27, 2019 at 6:53

1 Answer 1


Since this is a universal input supply (no selector switch) the primary side DC rail can run up to nearly 400V (230V for Europe allows a +10% tolerance to accommodate the UK), so you need to look for a bridge rated for at least that - if it's ever going to run outside of the US. As for current rating, 500W at 115V will draw about 5A, so that defines the minimum parameters of the bridge. Choosing a higher current rating is a minimal upcost, and a 600V PIV adds some safety margin - though usually at the expanse of a slightly higher forward drop and hence heat generated. Now all you need to do is find one of a similar package. Looks like the pin spacing is uniform, so it's likely one of the GBU style bridges, available from many manufacturers, will do.

enter image description here

This one is from OnSemi (formerly Fairchild for these products) but it's an industry standard non-standard, so there are many sources.

If the rectifier has failed, is it the only issue with this supply? Beware repairing a $50 supply when there's hundreds of dollars of hardware downstream that could be damaged.

  • \$\begingroup\$ Those measurements look about right on with the measurements I came up with. Width = 22mm Height = 18.5mm Thickness = 3.2 - 3.3mm I did already replace the bulk capacitor, a mosfet and have two resistors that are questionable because I'm not for sure how the color bands are read, linked here - electronics.stackexchange.com/questions/427995/… \$\endgroup\$
    – Pat
    Mar 27, 2019 at 19:12
  • \$\begingroup\$ Thank you @Phil G \$\endgroup\$
    – Pat
    Mar 27, 2019 at 19:30

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