Fw: [R-390] R-390A trouble

[Roger L Ruszkowski]

Jim,

We are doing this wrong.

Stop right here.

Put all the correct decks back into the original receivers.

Inject 150 uv at 455 into the IF deck and do the alignment
and setup.

Get the -7 volts on the diode load with function set to manual.
Get the 1 /2 watt across 600 ohms on the local audio output.
Check to see if you have the 30 db difference in signal plus noise to
noise.

either this all works wonderful, or the problem is localized to
the audio and IF deck (voltage was good)

Now switch the function to AGC. and hang the DC meter on the AGC
jumper.

Run the 150 uv up (300) and down (50) and watch the AGC voltage.
Listen for the putt putt.

Pop the Y2K open and see if the AGC voltage follows the book.

I hold out here for another leaking cap on a grid.
I'll even go so far as to predict its in the receiver.
I do not want to get committed to this yet.

The cap shorts, pulls a grip low, cuts off a tube, we hear pu,
the voltage falls below the break over voltage, the grid voltage builds,
we hear tt, the voltage increases to the flash over voltage, the cap
shorts.

If it is in the IF or audio deck, this test will find it.
If this test does not find it then

One tube and one injected voltage in to the RF deck at a time.
Depopulate the RF deck tubes.
Install the last 6C4 and inject 455 on it grid.
If that works install the PTO tube and inject 3-2 Mhz and mix 455 out.
Do some thing above 8 mhz for the next 6C4.

Do some thing under 8Mhz for the last 6C4.

God save you from the 6DC6.

Jim,

Other than the cat, this is the best mail all month.

Roger.