38-116 code 125 volume issues - Printable Version
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RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
Yes tube rectifier, I will have to see what the eletro caps are, the previous tech restuffed them, but I think he wrote on them what he used.
RE: 38-116 code 125 volume issues - Radioroslyn - 06-01-2020
The next thing after the caps are sorted is disconnect the primary of #102 and feed it w/an audio source and see how it sounds. #102 has hv fed on both ends.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
total disconnect primary ( both ends?)
RE: 38-116 code 125 volume issues - Radioroslyn - 06-01-2020
Yeah it's got hv coming from 78 and 118.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
I will see what this does. I think driver tube has too much bias voltage and too much plate voltage on it on it but there is no ref in voltage chart for bias on the screen on the driver tube. So we shall see.
RE: 38-116 code 125 volume issues - Radioroslyn - 06-01-2020
Ok... Remove the 6J5 driver tube and measure the resistance from pin 2 to pin 7 at the tube base not at the socket. Should see a low resistance of a few ohms.
> no ref in voltage chart for bias on the screen on the driver tube. So we shall see.
Good reason for it as the driver tube has no screen grid.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
I said screen grid, but missspoke, the grid has like -35v on it. Plate 361V
if you are wanting me to check the tube filament, I replaced the driver tube with a known good one and it made no difference.
RE: 38-116 code 125 volume issues - Radioroslyn - 06-01-2020
Ok #109,110, and 111 Check for bad connection or bad ground assuming that the resistor are with spec. Having that much -bias cuts the tube off so there isn't any plate current that's why the voltage on the plate is so high.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
That is that "cannedohm" 3 part resistor which specs ok but I will check for bad connections etc. I don't trust those resistors.
RE: 38-116 code 125 volume issues - Radioroslyn - 06-01-2020
>That is that "cannedohm"
The pictorial shows then as 3 individual resistors. I think you are looking @ 117.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
yep i was thinking of 117
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
I believe I have found the issue, it appears that previous technician placed a 50k resistor as a replacement for 109 instead of 490K (500k), now to find a 490k or 500k resistor.
RE: 38-116 code 125 volume issues - simplex1040 - 06-01-2020
That was the issue , it will blow your doors off now, I had not noticed that it was wrong until you pointed me in in the 109,110,110 area.
Thanks.