Advice needed - Identify a diode

[Caribo]

Hello everyone,

I need your enlightened help to identify a diode to replace.

Here's the context:

I have a monitoring active speaker, model PM5 from brand E-MU, which suddenly failed on me. I opened it up to see if I could find any clues to the malfunction, and came across components that seemed burnt. I cleaned up as best as I could. The capacitors are easily identifiable for replacement, but I have absolutely no idea how to find the reference of the diode to change, D105. This one is probably the same as D106. The regulator behind it is an LM337SP.

As I'm writing this message, I thought I'd take a look at the LM337SP datasheet, to see if there were any examples of setups involving diodes. There's one with 1N4002 and 1N4148. Given the package, I don't think it's a 1N4002.

Could it be a 1N4148? If someone could enlighten me, I would be greatly appreciative!

Thanks in advance!

[fzabkar]

It would help to know where the diode connects. Is one end grounded? Does it connect to any of the regulator's pins?

[isometrik]

Based on the symmetry of the components in that area of the PCB, I suspect D105 is identical to D106, as you suggested in your initial post.

I suggest you desolder D106 to read its part number.

[Haenk]

The package and size would match a 1N4148.
It is certainly not a 1N400x - these are all plastic packages.
Unfortunately, this only helps to rule out things, but is no confirmation. In my opinion, a 1N4148 will do.

[Caribo]

A big thank you for your initial responses.

I found a way to read what's written on the package: 1N4 and below it, a 5.

Could this help someone?

Thank you

[fzabkar]

1N45 is a germanium diode, which is a relic from the past. It would help if you identified the connection points. Does it connect between Vin and Vout, or between Adj and Vout, or between Adj and Ground?

A germanium diode would make some sense if it were connected between Vout and ground, reverse biased.

From National Semiconductor's handbook:

Figure 4-2 is an example of a typical connection for obtaining a positive and negative power supply. The diodes between output and GND are for preventing latchdown at startup and are absolutely necessary in the case of loads shown by solid lines. Without the diodes, current flows in the separation regions between elements as described in Figure 4-2 is an example of a typical connection for obtaining a positive and negative power supply. The diodes between output and GND are for preventing latchdown at startup and are absolutely necessary in the case of loads shown by solid lines. Without the diodes, current flows in the separation regions between elements as described in chapter 2 and the output voltage does not rise (refer to Figure 4-3).