2nd tuner has bad reception issues on DirecTV TIVO Series 2

[tas3086]

... the tuner chips are CX24109-11, U2000 (tuner 1) and U2001 (tuner 2). A VERY quick glance at the datasheet indicates it uses a single 5V supply. VR5 and VR6 are 8M05 5 volt regulators next to the tuner chips. A quick check with a DMM (measure the resistance between the output of VR6 and the Vcc pins of U2001) would verify they regulate the supply voltages. If that checks out, the easy way would be to solder a 220µF low ESR cap between the output and ground pins of VR6.

The caps in the area are electrolytics in an SMD package; these are more prone to failure than thru hole types.

PlainBill

I just added a 1000uf cap on VR6, and it is working perfectly, having had a severe pixelation problem.
Thanks

[PlainBill]

I just added a 1000uf cap on VR6, and it is working perfectly, having had a severe pixelation problem.
Thanks

Glad to hear it.

For others who have the same problem, I'd like to add that this is a situation where 'more is better' does not necessarily apply. I would not have used a 1000µF cap; a 470µF is as large as I would go, with a 220µF, 16Volt as the preferred value.

PlainBill