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==Internals==
==Internals==


The input is switched via a Frequency compensated attenuator network which is controlled by the Vols/CM Switch.
The input signal traverses a frequency-compensated attenuator network controlled by the Volts/cm switch,
Input is then coupled to first cathode follower V5832, a 5654/6AK5W RF Pentode.  
and is then coupled to the first cathode follower tube (V5832), a [[5654]]/[[6AK5W]] RF pentode.  
The screen supply of this cathode follower is switched from +100 to a decoupled network from +225V rail when the X10 Mode is selected.  
The screen supply of this cathode follower is switched from +100 V to a decoupling
network fed from the +225 V rail when the ×10 Mode is selected.  


The output of input amplifier is then switched via a 10X Amplifier - if the X10 mode is selected in the front panel - or directly to the paraphase or phase inverter made up of two [[12AU6]] tubes. This stage converts the input signal to a differential push-pull output. This output is passed to the final output drivers, which are two cathode follower sections with a pair of [[12AT7]] tubes. The differential output is then passed to pin 1 and 3 of the connector to drive the vertical amplifier inside the chassis.  
The output of input amplifier is then switched via a 10× amplifier (if ×10 mode is selected) or  
directly to the paraphase or phase inverter made up of two [[12AU6]] tubes. This stage converts  
the input signal to a differential push-pull output. This output is passed to the final output drivers,  
which are two cathode follower sections with a pair of [[12AT7]] tubes. The differential output is then  
passed to pin 1 and 3 of the connector to drive the vertical amplifier inside the chassis.  


The 10X amplifier stage is built with 3 5654/6AK5W tubes. First two are configured as amplifier and the last one as output cathode follower.
The ×10 amplifier stage is built with three 5654/6AK5W tubes, the first two of which are configured as  
amplifiers, and the last one as an output cathode follower.
   
   
Diode D5972 on the first 5654/6AK5W amplifier V5942 tube's cathode is used to protect the cathode bypass capacitor C5972. C5972 is a 500 μF/6V cathode bypass Capacitor.
The diode D5972 on the first 5654/6AK5W amplifier tube's cathode (V5942) is used to protect the cathode bypass capacitor C5972, a 500 μF/6 V electrolytic, in case someone would pull out V5942 with power applied,
In case someone pulls out V5942 and power on the plug-in, the cathode bias of -150V will come across C5972 and can potentially destroy it. This diode is used to prevent such scenarios and to drive the voltage to ground via R1958 (12K) if such condition occurs.   
in which case the cathode bias of −150 V would come across C5972 and destroy it.   


 
Heater supplies for the tubes are derived from the +75 V<sub>DC</sub> supply available at pin 15 of  
Heater for the tubes are derived from +75VDC heater supply available at pin 15 of the connector. This is to avoid any interference/hum from the regular AC heater supply at 60Hz.  
the mainframe interface, to avoid any mains interference/hum from the regular AC heater supply.


==Pictures==
==Pictures==
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