Pretty far down the rabbit hole with this one, and I've come across a few questions:
- there's an old paper cap that doesn't give consistent readings and the paper doesn't show the rating, so i'm trying to figure out what i should replace it with. it's 0.7" wide and 2" long, same length and just a hair thinner than the .1Mfd/1kV paper caps on the board, so that's a good reference. it's part of a capacitor-resistor to ground in parallel with the main HT+ from the 5R4 cathodes, and that pair are the first and only components before the HT+ goes through a massive choke. the manual for a similar model, the A3A, shows the same CR pair in the same configuration, and states its only purpose is to filter out transient oscillations present in choke input filter systems. on that model's schematic, it's a .02Mfd/1.6kV cap in series with a 1K resistor, and on my D6, the resistor is exactly the same value and appears to be a 1W. however, my model is significantly more powerful than the A3A, and as such i'm wondering if i should increase the voltage and/or capacitance values. what i've settled on to start with is sticking with a .02 since the resistor value is the same, and giving a huge voltage cushion with a 15kV rating. thoughts?
- the mains fuse for the unit is rated at 6A. what AWG should the power cord be? from what i can gather i should be using at least a 14AWG to handle that much current, but the wires on there seem to be 18 or 16.
- i got lovely new can caps from the fine folks at justradios.com, but i didn't realize they wouldn't have the 4 ground lugs to affix them around the outside, just the positive terminals and one neg terminal in the middle! any suggestions as to how to affix this sucker to the chassy? they're Richey Golds, 2x 40Mfd/500V.
- giant metal box capacitor first in line for the HT+ filters, it's a Mallory Transmitting Capacitor, 1Mfd/2kV, model TX-810. reading within a 10% tolerance at 1.09Mfd. i'm not familiar with the type of construction for these - are they more like vintage paper or electrolytic caps, where even if they're measuring on spec they're likely to go bad soon anyway? or are they more like wirewounds where it's better to leave it unless it's measuring way off mark?
- there's an old paper cap that doesn't give consistent readings and the paper doesn't show the rating, so i'm trying to figure out what i should replace it with. it's 0.7" wide and 2" long, same length and just a hair thinner than the .1Mfd/1kV paper caps on the board, so that's a good reference. it's part of a capacitor-resistor to ground in parallel with the main HT+ from the 5R4 cathodes, and that pair are the first and only components before the HT+ goes through a massive choke. the manual for a similar model, the A3A, shows the same CR pair in the same configuration, and states its only purpose is to filter out transient oscillations present in choke input filter systems. on that model's schematic, it's a .02Mfd/1.6kV cap in series with a 1K resistor, and on my D6, the resistor is exactly the same value and appears to be a 1W. however, my model is significantly more powerful than the A3A, and as such i'm wondering if i should increase the voltage and/or capacitance values. what i've settled on to start with is sticking with a .02 since the resistor value is the same, and giving a huge voltage cushion with a 15kV rating. thoughts?
- the mains fuse for the unit is rated at 6A. what AWG should the power cord be? from what i can gather i should be using at least a 14AWG to handle that much current, but the wires on there seem to be 18 or 16.
- i got lovely new can caps from the fine folks at justradios.com, but i didn't realize they wouldn't have the 4 ground lugs to affix them around the outside, just the positive terminals and one neg terminal in the middle! any suggestions as to how to affix this sucker to the chassy? they're Richey Golds, 2x 40Mfd/500V.
- giant metal box capacitor first in line for the HT+ filters, it's a Mallory Transmitting Capacitor, 1Mfd/2kV, model TX-810. reading within a 10% tolerance at 1.09Mfd. i'm not familiar with the type of construction for these - are they more like vintage paper or electrolytic caps, where even if they're measuring on spec they're likely to go bad soon anyway? or are they more like wirewounds where it's better to leave it unless it's measuring way off mark?
I have access to a manual for the D6, at the Antique Wireless Museum where I volunteer. I can copy or scan it, if you'll send them a donation in return...
Cap after the rectifier could be at least .02 @ 1600V or more.. (0.047 @ 1600V prevented SS rectifer failures in a 280V/20A choke input filter I worked on) 18 ga cord is good for 10A, 16 ga for 13A. What's the cap diameter? There are clamps to mount them. The oil cap is probably fine.
Cap after the rectifier could be at least .02 @ 1600V or more.. (0.047 @ 1600V prevented SS rectifer failures in a 280V/20A choke input filter I worked on) 18 ga cord is good for 10A, 16 ga for 13A. What's the cap diameter? There are clamps to mount them. The oil cap is probably fine.
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Hi Tom! Was the manual for this ever made available? I have a seemingly intact D6 and I'd like to bring it into this century.
Yes, I have a scan, but it's missing the last page - the schematic. Download here: https://we.tl/t-GcGyyDQfpX
