#1
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VT-71 Ballast 17A485459 in a TS-4D?
I picked up one of these ballast tubes years ago when there were plenty on ebay. I am sure this topic has probably already been beat to death. Here and elsewhere, but.
I stuck it in my 4D but it obviously didnt work after some research as they made 2 different tubes and I was unaware at the time. So, Is there a modification that can be done to allow the 17A485459 Ballast to work on the TS-4D? Just curious. Last edited by mbates14; 06-03-2018 at 09:55 AM. |
#2
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Doing some more searching, I found this:
http://antiqueradios.com/forums/view...80269#p2680269 Basically states that they removed resistor E, and moved the common tie point from pin 5 to pin 6. So technically I could swap the wires from 5, and 6, but then I lose the 22 Ohm resistor. But according to the TS-4D schematic, that resistor is in parallel with the audio preamp tube filament. Question is, Why? and what would happen if it was "missing"? |
#3
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Quote:
The 6SQ7 is a 300ma tube so the resistor has to be in parallel with the heater to equal 600ma. 22 ohm and at least 2 watt. |
#4
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Thanks for the explanation, clears that up!
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#5
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Just a question about the ballast does anyone have a list of the ballasts used on the specific chassis I swear I had one somewhere but I just can't find it now would be handy to have
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#6
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only the ts-4j late uses the 17A485459. All the others use the 17A470303
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