[AMRadio] APA-38 panoramic Help

doxemf at aol.com doxemf at aol.com
Sun Jul 11 14:36:44 EDT 2010

Does anyone have experience with or a manual/conversion docs for this panoramic unit?

This is a long narrow body unit that was used with the APR-4 search receiver and in the PBM-5S Mariner Aircraft from what little info I have been able to find.

The crt has about a 2-1/3 diameter round screen. Power supply was internal 400cy >

The original IF input frq was 30 mhz with the units own IF at 6.5. 

The two units that I have were modified to use an external 60cy transformer that I have, and there is a crystal controlled converter strip added using 2 miniature tubes, a 243 case 6.XXX xtal and 3/4" transformers. This strip looks like a factory build and mounts where the original converter circuit was.
 The schematic is included in an old CQ conversion handbook but nothing is documented for the converter altho conversion for 455 is mentioned.

 I suspect that the units that I have could have been late production with the converter or possibly a published mod.
Since the original circuitry was MFP treated it is difficult to troubleshoot without a good parts layout. The converter has not been treated and easily accessable.
One unit does power up but there are leaky capacitor issues evident from an erratic display trace.

If anyone might have further info or can point me to a manual or magazine issue with the full conversion it would be appreciated. This is a nice small Panoramic display similiar to the Halli Skyrider accessory.

KB3DKS in 1 Land

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