[R-390] Still wondering about the 100mV detector test

[Flowertime01 at wmconnect.com]

Barry,

The real old test from the TM is as follows.

Line gain to max
Local gain to max
RF gain to max
Mode to MGC
Bandwidth to 2KC
BFO off
Line meter to +10


Hang a DC voltmeter on the diode load.
Hand a TS585 on the line output. 
(AC volt meter with DB scale and 600 ohm resistor)
Inject about 150 micro volts of 455 with 30% modulation into the IF deck.
Set the gain adjust or the signal generator for - 7volts on the Diode load.

Read at least 400 milliwatt or +26 DB on the audio output.
This should be +2 VU on the line meter scale.

A good receiver will get you 500 milliwatt.

This is a go no go test.

You either got -7 volts and at least  .4 watt out or you have an audio deck 
problem between the diode load and the point you are measuring (line out or 
local out on the terminal board).

150 UV at 455 should get you an easy -10 volts on the diode load or you have 
an IF deck problem before the diode load. IF deck problems manifist more as 
not making signal to noise ratio than not having enough gain. 

If both line and local fail its the common stuff. If only one audio channel 
fails its in that channel.

All the other test are just to help narrow problems down.

Any thing you read any where between the original TM and an Email today is 
subject to the same disclaimer. Errors in print do happen.

Do the test and put you anxiety to rest.

Your off looking at these point that change with every tube.
Pick a point near a tube. Swap at least three tubes into the circuit and 
measure the same point with no change except to swap the tube. Wait for the tube 
to warm up and settle down. Take a reading. If you get two tubes that give you 
the same meter reading you are lucky. 

Roger AI4NI