letterbeacon
Well-known member
Ages ago, back in 2015 I built an RCA BA6A using original transformers etc. with huge amounts of help from the good people of this forum. It sounded great, but then I had to put it in storage and it hasn't been used in about a year.
The other day I got it out and turned it on. It was working for a bit, but then the purple light on the 0D3 went out and the meter went back to 0.
I've ordered another 0D3, put it in the socket and I'm getting no purple light on the new 0D3.
I've measured the voltages at the pins of all the sockets and I have the following:
6SK7
V1 Pin 8 = 145vdc (135) 299
V2 Pin 8 = 140vdc (135) 299
V1 Pin 6 = 96vdc (103) 1.2
V2 Pin 6 = 96vdc (103) 1.2
V1 Pin 5 = 4.79vdc (5.15) .02
V2 Pin 5 = 4.80vdc (5.15) .02
6J7
V3 Pin 3 = 69.5vdc (71) 56.3
V4 Pin 3 = 43.8vdc (71) 83.4
V3 Pin 4 = 36.3vdc (42) 43.4
V4 Pin 4 = 36.3vdc (42) 43.4
V3 Pin 8 = 1.10vdc (1.18) 1.2
V4 Pin 8 = 1.19vdc (1.18) 1.1
6V6
V5 Pin 3 = 269vdc (275) 292
V6 Pin 3 = 269vdc (275) 291
V5 Pin 4 = 277vdc (285) 301
V6 Pin 4 = 277vdc (285) 301
V5 Pin 8 = 14vdc (13.1) 17.1
V6 Pin 8 = 15.57vdc (13.1) 17.2
6H6
V7 Pin 4 & 8 = 63vdc (66) 1
0D3
V8 Pin 5 = 146.4 (155) 1.49
5R4GY
V9 Pin 4 & 6 = 565vac (315vac) 579
The first number is what I measured back when it worked in 2015, the number in brackets is what RCA says I should expect at that point, and then the third number is what I'm measuring now.
It looks like the 0D3 is definitely not happy, nor are the 6SK7s and the 6H6.
I suppose there is a chance that the new 0D3 is not working - I'm told by the eBay seller that it was tested though.
Does anyone have any ideas?
I've attached the schematic and here's some DIY build porn...
The other day I got it out and turned it on. It was working for a bit, but then the purple light on the 0D3 went out and the meter went back to 0.
I've ordered another 0D3, put it in the socket and I'm getting no purple light on the new 0D3.
I've measured the voltages at the pins of all the sockets and I have the following:
6SK7
V1 Pin 8 = 145vdc (135) 299
V2 Pin 8 = 140vdc (135) 299
V1 Pin 6 = 96vdc (103) 1.2
V2 Pin 6 = 96vdc (103) 1.2
V1 Pin 5 = 4.79vdc (5.15) .02
V2 Pin 5 = 4.80vdc (5.15) .02
6J7
V3 Pin 3 = 69.5vdc (71) 56.3
V4 Pin 3 = 43.8vdc (71) 83.4
V3 Pin 4 = 36.3vdc (42) 43.4
V4 Pin 4 = 36.3vdc (42) 43.4
V3 Pin 8 = 1.10vdc (1.18) 1.2
V4 Pin 8 = 1.19vdc (1.18) 1.1
6V6
V5 Pin 3 = 269vdc (275) 292
V6 Pin 3 = 269vdc (275) 291
V5 Pin 4 = 277vdc (285) 301
V6 Pin 4 = 277vdc (285) 301
V5 Pin 8 = 14vdc (13.1) 17.1
V6 Pin 8 = 15.57vdc (13.1) 17.2
6H6
V7 Pin 4 & 8 = 63vdc (66) 1
0D3
V8 Pin 5 = 146.4 (155) 1.49
5R4GY
V9 Pin 4 & 6 = 565vac (315vac) 579
The first number is what I measured back when it worked in 2015, the number in brackets is what RCA says I should expect at that point, and then the third number is what I'm measuring now.
It looks like the 0D3 is definitely not happy, nor are the 6SK7s and the 6H6.
I suppose there is a chance that the new 0D3 is not working - I'm told by the eBay seller that it was tested though.
Does anyone have any ideas?
I've attached the schematic and here's some DIY build porn...