Cheaper to just buy another UHF MaxTrac or Radius and swap the PA outright. By the time you figure in the troubleshooting and repair time to replace Q2740, you'd be better off with another radio and keep the best looking and working parts.
Bob M. ====== --- On Sat, 6/7/08, Eric Lemmon <[EMAIL PROTECTED]> wrote: > From: Eric Lemmon <[EMAIL PROTECTED]> > Subject: RE: [Repeater-Builder] Maxtrac Question > To: Repeater-Builder@yahoogroups.com > Date: Saturday, June 7, 2008, 10:57 AM > Tom, > > It appears that the final transistor Q2740 is dead, and the > driver > transistor Q2730 is running wide open. The driver normally > provides about > 13 watts to the final. Check all solder joints and verify > the correct DC > voltages are present during transmit. An RF millivoltmeter > can be a great > help in troubleshooting this problem. > > The complete MaxTrac service manual 6880102W84 is available > for download on > the RBTIP, and Part 4 of 4 covers the power amplifier. The > 17.1 MB file is > here: > <www.repeater-builder.com/maxtrac/files/maxtrac-manual-6880102w84-o-4-of-4.p > df> > or as a TinyURL: > <http://tinyurl.com/5qoar8> > > Let's hope that the final PA transistor is okay, > because it (4880225C24) > costs about $110 from Motorola. I did a cursory search on > the Internet and > found a supplier in Mexico selling the same part for about > $65. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of > tgundo2003 > Sent: Friday, June 06, 2008 10:52 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Maxtrac Question > > I have a UHF (D44) 40w 449-470 maxtrac on the bench. All > checks out > good, except power out. Most I can get out of it is 22 > watts, and that > happens at 92 on the adjustment scale, any values above 92 > yield no > difference in power output. > > Here is the strange thing- I get more out (22W) at 441.300, > and only > 14w at 467.xxx. Since this is a 449-470 split I would think > it would > be the opposite. > > Anyone have any thoughts? > > Tom > W9SRV
