Be suspicious of the power control pot first. Chuck WB2EDV
----- Original Message ----- From: "Joe" <k1ike_m...@snet.net> To: <Repeater-Builder@yahoogroups.com> Sent: Monday, February 23, 2009 7:29 PM Subject: Re: [Repeater-Builder] MASTRII 100 watt PA question > Hello Eric, > > Thanks for the tip. Last night, the PA failed again. I went to the > site and found that the problem is in the 10 watt PA stage, possibly the > IC chip or the power control transistor. I brought it home and will > look at it in more detail. The strange thing was that it came back to > life yesterday, just like a bad connection would cause. > > 73, Joe, K1ike > > > Eric Lemmon wrote: >> Joe, >> >> Use a magnifying glass to closely check every solder joint for cracks. >> Some >> such cracks appear due to temperature cycling over time. I have already >> had >> the same problem, where a PA was dead at the site but worked fine on the >> bench. It was around 40 degrees at the site, but around 70 at the bench. >> Sure enough, a tiny crack had opened on a PA power lead. Reflowing >> solder >> at that connection cured the problem. >> >> 73, Eric Lemmon WB6FLY >> > > > > ------------------------------------ > > > > Yahoo! Groups Links > > >
