I don't see any marking on these diodes that I need to replace some of them.

Here's the data I got:

Voltage drops: about 0.59 volt
diameter: 1.75 mm
width: 2.82mm

Please see attached images. Majority of the bad one have cracks on the glass.

 

Hello,

The COULD be 1N914 or 1N4148.
Those are low power diodes.

Bertus

 

That's probably it. The two appears to be very similar. I couldn't find something around 0.6V drop. There are so many 1V drop diodes out there. It's strange that google shows silicone diodes are 0.5v to 0.7v, which is right on my range, but I couldn't find them.

According to this: https://www.digikey.com/en/products/detail/onsemi/1N914-T50A/4743901

It's the max forward voltage. The data sheet show 0.63v at 5 mA.