Help determining bad part

Most likely it is one of the coaxes from the dish to the SWM8 is bad/corroded.  A new SWM LNB only needs one coax from the dish to a SWM splitter plus a 21v power inserter and can have 13 tuners.   DTV no longer uses the 119 sat for US programing so you don't need an SL5 LNB.

This is a "legacy" commercial install that I was called to work on after many years away from and many years away from DirectV. The dishes are on the roof of a building 32ft with no roof access so it's a ladder or a lift.  As long as the lnb is being fed voltage from one of the lines via the SWim8 can the LNB be read to determine the problem?  I need to determine exactly what the problem is either the SwiM or the Coax/LNB. Would a super buddy be better for this task? Ultimately I want to read RF on the coax but not sure how it will be presented from the LNB.

@mikefleming

I would First Suggest looking at all the outside COAX Connectors -as was suggested bad coax is your problem. 

If it is a Commercial account -they should be able to Call in a Service repair with D*TV 

They may no longer require a 5LNB for service if so you could change them out to a SWM 5 LNB or a SWM 3 LNB -all of which is expense like a lift or renting 28' or 40' Ladder. You may need to get to the roof to see if any exposed rg6 Connectors are exposed as well. 

It is a hybrid system.  The SWM8 sends 13v on 2 coaxes and 18v on the others to power the even/odd transponders for each sat LNB and you are most likely missing the voltage that powers the 103 odd transponders.

Is the AIM meter capable of reading the inputs/lnb from the dish? Before I order parts I'd like to know for sure whether it's the SWiM or the coax/lnb.

If it can supply the 13/18v needed to power the transponders then yes.

That is what I am trying to figure out, technical info on this is pretty hard to find. Can the AIM output 13/18v to power the LNB or do I have to have a power supply in the circuit? 

Can you point me to any training materials? I found swm8.com but it seems to be very dated/outdated. 

Unfortunately, we are not able to provide that information.

Sounds like a question for Solid Signal to me.