arcanaking

Thanks jamesmking. I finally find out the reason. Thanks for your suggestiosn. I switch the multimeter to dc voltage to check the transformer and capacitors and I finally notice that the right cap is flipped and I use the negative pin to connect the ground. I misunderstand that all the capacitors should connect to gnd by negative pin and thus the capacitor cannot discharge. After I flip back the cap, everything work normal. Thanks again for helping me to tackle the problem.

Thanks jamesmking. This is my transformer's information. It is a 50VA 25V toroidal transformer. I shorted the red (25v) and orange (0v) and connected to the gnd. Thus, it will perform 50v output when the probes are on the left and right pad in input socket. I have tested the voltage reference as the guide, the positive side is 10v in stable. Yet, the negative side starts with 10v and drops quickly. Most of the parts are from mouser. Only some DN2540N3-G, MJW21193G and MJE15030G are ordered in Element14 because mouser has no stock currently. Here are more photos of the components' details.

Hi All, I am building the GRLV 2018 version.48 and I get a problem which I have no idea to tackle it. Before I soldering all the parts, I checked the position of ksp92 and ksp42 and confirmed they are put in the correct position. When I plug the 50VA transformer to provide double rails 25v to the GRLV, all the LED will light up but only the LED which near the zener on right side will dim soon. I use the multimeter to check the output voltage and I found that the positive rail provide stable 20v but the negative rail will keep dropping the voltage every second from 20v. Can anyone tell me why the negative rail keep dropping voltage? Do I mess up the polarity or put the component in a wrong place and thus lead to this problem?

Hi all, sorry for requiring the pdf/gerber. I am trying to build my CFA3 with the balanced audio protection board. Yet, it seems hard to find the gerber or pdf of the protection board in other threads. Can anyone tell me if it is a must to use the protection board? If yes, where can I find the document?