Repairing & Troubleshooting Receivers

[VSATDISH]

Hello All,

I tried the search and couldn't hit on the right words so here's my ?

I have a 4900 that won't switch LNB's - in other words the DC switching voltage to the antenna is stuck - only sees one satellite

I have a 2700 that has an audio hum - usually caused by a bad electrolytic cap gone bad

Anyone know of any troubleshooting logs or guides or schematic walk throughs that address these issues? I know receivers are cheap on ebay but I'm more into 'testing' than hook up and go - to me troubleshooting is fun.........

Thanks.................

[skinerd]

The 4900 maybe an easy fix, there is a larger transistor that will sometimes short, if that is case, the output volts will tend to be 18+.

The 2700, shotgun every cap in or near the audio/video section, prolly cost you 5 or 6 bucks.

If you have access to a scope, scope the power supply outputs, see if one is particularly noisy, change associated caps there if so.

[VSATDISH]

Thanks for the Feedback.............

I'll post if I figure anything out.

[t160hq]

If your into troubleshooting electronics one handy and
inexpensive tool is the cap analyzer 88 by
Electronic Design Specialists.

It checks ESR of caps in circuit. Costs about 100 bucks.

Started fixing my own electronics and most of the time just
checking ESR on all the caps and replacing the bad ones
fixes most if not all the problems so far.