[Hallicrafters] SX-42 Help Needed

[Carl]

Start at the PS and all audio stages to prevent expensive damage to the 
power and audio transformers.

Replace the electrolytics and paper caps associated with those stages 
and check resistor tolerance.

Now you can proceed with stage by stage overhaul knowing that voltage 
measurements will be correct (unless there are problems in those stages) 
and the audio should be fine.

I like to work from the audio back to the RF when recapping and 
replacing resistors. If you start with the RF you dont know where that 
sudden distortion came from as it could be anywhere.

Expect 15-20 resistors to be well out of tolerance.

Carl
KM1H


----- Original Message ----- 
From: "Joe Connor" <joeconnor53 at yahoo.com>
To: <hallicrafters at mailman.qth.net>
Sent: Sunday, February 15, 2009 8:43 AM
Subject: [Hallicrafters] SX-42 Help Needed


>
> Well, I picked up the SX-42 and it was as advertised: strong on FM but 
> weak on AM. I did some signal injection.
>
> On the lower four bands, a 455-khz signal injected into the 1st IF 
> gave strong output. An RF signal on the plate of the 2nd RF gave 
> strong output. An RF signal at the input of the 2nd RF gave distorted 
> output. An RF signal in the 1st RF gave weak output. The volutages in 
> the 1st and 2nd RF test normal.
>
> Where do I go from here?
>
>                         Joe Connor
>
>
>
>
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