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EAR834 Clone No DC voltage to the DC 285

Hi Everyone, I am working on a build, and everything is wired. I tested the power on the AC 230- 380V without the tubes in it. I got 300V DC, like the video shows. I then add the tubes, and I get nothing. I also don't get anything when I test the DC285V. I then check the measurements for the choke, and I get 70V, which seems very high for a Hammond 154E that has a max of 20V. Any ideas where I may have gone wrong?

Thanks,

Greg

5 answers0 replies

5 Comments

Skunkie

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Ground one lead and the start looking for DC, first on each side of the choke and then on the other large resistors and try to see where the voltage disappears.

Greg Brophy

Replying to

Great, thanks. I will give it a try.

Greg Brophy

Replying to

OK so I have tested it and I get: Choke input 310VDC Choke output 256VDC

3K3 3W input 0V

3K3 3W ouput 136VDC 20K 3W input 29VDC

20K 3W output 0VDC

I tested the resistance of the 3K3 3W and get 3K3 and the 20K reads at 20K. I reflowed the solder take make sure it is ok but I am still not getting anything else. Do I need to replace the resistors? I have an extra 20K but I need to order the 3K3.

Thanks,

Greg

Greg Brophy

Hi Skunkie, thanks for responding. I just wanted to update this to add more detail. This is my first build. I am using the board as one, I did not split it. I am not sure if that makes a difference. I tested the AC without tubes, and I get 300V. I tested it with tubes, and I get 256V.

I read the DC285 with the red probe and the black probe to ground, and I get nothing. The choke is installed ( I assume it doesn't matter which wire goes where in the 1k1 3w holes) . The transformer is a Hammond 369ax. On the transformer, since I am getting the right AC, I assume it is working ok. I have the white and brown wires go to the middle pin of the outlet. The two red go to the AC in the center, and the two green go to the AC on the left. The black and blue wire is going to the power switch. I also tested the first capacitor in the power supply side of the board, the 100UF 450V, which came to 326V. All the capacitors are what was suggested in the parts list.

The chassis is wood with a copper and aluminum plate as the top based. I will add some photos. As for the 20v, sorry I mixed up the specs on the 20mA as 20V.

Thanks again,

Greg

Skunkie

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No sure where you got the spec that choke is only rated for 20V. It's rated for 300V.