Motorola SM50 RX Deaf

[Satelite]

Hello:
Oh boy back in the old day time now.
I have a Motorola SM50 45 watt 2 ch VHF mobile coming in soon and its been so long since I repaired or even programmed one that my memory isn't well remembering.
Cant find my sm50 manual at the momement but its here gotta move crap to find id qeuss.
Ayway it is the 25 kHz wide band model on ham freq and a local weather freq ch as rx only for the guy.
He says transmit / wattage / modulation / Others say he sounds great in tx mode so assuming that means hes on freq as well but he has almost no receive sensitivity as I get it from his info given.
Aparentlty if other ham talking to him is close enough he can hear them but not if the are just a few miles away.
He used to be able to hear close to 25 miles or better out as he tells it and no longer hears the weather freq channel other than once in a great while he might touch a long metal rod antenna to the rf connectors center pin then hears bits and pieces of the weather broadcast but never complete clear just busted up pcs of the broadcast.
So apparently hes lost rx sensitivity for receiver operation.
So my question before the radio arrives is what was the main culprits you recall that could cause the rx deafness and if you have it the schematic part id number on the sm50 schematics ?
Appreciate your patience and replys.
Thank you
Satelite

[kcbooboo]

Service Manual

[Satelite]

Hello:
Service manual you say = well that was a lot of help.
I already said id have to find it.
Satelite

[jackhackett]

If you can't find your manual you can get it on the repeater builder site.

Often weak receive is caused by the diodes in the front-end being fried. Unfortunately I believe the diodes in the SM50 (CR1) are under one of the soldered on shields, which makes it a bit harder to get to.