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 Help please Info on Classic schematic
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 Return to top of page · Post #: 1 · Written at 11:31:58 PM on 25 June 2025.
Wazzadj's Gravatar
 Location: Churchill, VIC
 Member since 2 December 2024
 Member #: 2693
 Postcount: 9

Hi Admin (Brad) please excuse me if this post does not belong here not sure

Hi Brains trust, can you please verify the Classic schematic diagram attached where the Voltages are noted and marked on the diagram
I am a little confused if that is the voltage marked or the resistance on the schematic as I note some of the resistors value are not marked on the schematic
for eg the 6AQ5 valve diagram where the heater supply comes in their is a 265 denoted is that a vs reference ?
I have noted: the resistor is a 250ohm in that postion , so I take it that's the expected voltage supply across that junction is that correct?
as the capacitor next to it is marked 25μF
all so the .004 or .05 I presume is the mV ( Millivolts) or is it mA (milliamps)?
am I reading this schematic correctly ?
Thankyou kindly for your assistance.

cheers

Classic TG Circuit Diagram


 
 Return to top of page · Post #: 2 · Written at 1:07:28 AM on 26 June 2025.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2226

The cathode components indicate 265 ohm resistor, and a 25μF electrolytic capacitor. The cathode voltage should be 12.5 volts.

.004 next to the capacitor indicates 0.004 μF, while .04 next to the resistor indicates 0.04 Megohm (or 40 kOhm if you prefer).

The only voltage on the schematic is where it says 2,275 (as in 2x 275 volt secondary windings) next to the power transformer, and there's no millivolts or milliamps anywhere.

In my opinion you should learn about schematics before attempting to do repairs.


 
 Return to top of page · Post #: 3 · Written at 6:08:11 AM on 26 June 2025.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7574

Document uploaded.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 4 · Written at 11:14:10 PM on 26 June 2025.
Wazzadj's Gravatar
 Location: Churchill, VIC
 Member since 2 December 2024
 Member #: 2693
 Postcount: 9

.Robbert
Thankyou for your clarification , I am now more educated in the obscure method of vintage schematic markings
i do not under stand why they just couldn't write a 40k instead of .04 seeing they wrote 2k on the other one
anyway I will now go decipher and write all the values and compare


 
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