UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - HA12411 FM IF chip

ms660 · 5th Aug 2019, 1:21 pm

The Mitsubishi DA-F20 has H and V multipath outputs it uses a similar IC (HA1137) vertical from pin 13 and horizontal from the audio output (pin 6) via some coupling capacitors.

Link to schematic here:

https://elektrotanya.com/mitsubishi_...wnload.html#dl

This is just to assist in tracing the circuit in the above schematic....In that schematic there are two IF paths for FM, wide and narrow, the HA1137 is configured for narrow band, for wide band the detector uses a familiar discrete components circuit, the narrow/wide selector switch for the two different bandwidths is S1b in the schematic, the left hand section of S1b doing the selection between the two audio outputs from the two separate detectors.

EDIT: I scrubbed my original post due to an error I made, the above is the re-written replacement.

Lawrence.

5th Aug 2019, 1:21 pm	#6
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: HA12411 FM IF chip - who used it? The Mitsubishi DA-F20 has H and V multipath outputs it uses a similar IC (HA1137) vertical from pin 13 and horizontal from the audio output (pin 6) via some coupling capacitors. Link to schematic here: https://elektrotanya.com/mitsubishi_...wnload.html#dl This is just to assist in tracing the circuit in the above schematic....In that schematic there are two IF paths for FM, wide and narrow, the HA1137 is configured for narrow band, for wide band the detector uses a familiar discrete components circuit, the narrow/wide selector switch for the two different bandwidths is S1b in the schematic, the left hand section of S1b doing the selection between the two audio outputs from the two separate detectors. EDIT: I scrubbed my original post due to an error I made, the above is the re-written replacement. Lawrence.