In a linear power supply (without schematics) I am currently repairing (and learning valuable stuff) I identified a probably faulty diode, that has shortened.
As the Model (Motorola MR501) is not available anymore, I would have to look for a good quality replacement.
As the general question how to look for replacement for ancient standard parts probably is of use for other people, I put it in as a separate thread and not under the repair thread for the Power Supply (
https://www.eevblog.com/forum/repair/hdl-research-lab-military-power-supply-lcd-replacement)
@mods: If not ok, could you merge it then?
I would ask for some advice on how to select a replacement diode for this application.
From what I already looked up in the datasheets are the obvious things like same case, rated voltage, similar reverse/forward voltages and not to forget the heat dissipation in dependency of the mounting conditions.
But: What about the frequency response, resp. behaviour under load? In this regard, I would appreciate any tips from practical experience.
FRom the datasheet
https://www.datasheets360.com/part/detail/mr501/-5038348702330472923/ I see the following values:
Motorola MR501
Standard Recovery Power Rectifiers
50-1000 Volts
3 Amps
Case 267-01
Peak Repetetive Reverse Voltage/DC Blocking Voltage(VRRM/VRWM/VR): 100
Non-Repetetive Peak Reverse Voltage (VRSM): 150
Average Rectified Forward Current (IO): 3 Amp
Instantaneous Forward Voltage (VF): Typ 0.9, Max 1.0 Volt
Reverse Current (IR) Typ. (25 Deg C) 0.1, Max 5.0 µA
100 deg C Typ. 2.8, max 25 µA
Dimensions: 5 mm diameter, length 9,5 mm
From what I have seen, I concluded that some standard 1N5408 diode could be a possible replacement? But those (at least the Onsemi 1N5408RLG my favorite shop is carrying) have some higher max. reverse current of 10 µA instead of 5µA of the Motorola version.
What negative effects could this yield?
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