In addition to checking the solder joints on the transistors, check the connection between the PA output and the harmonic filter. This is another prone intermittent point.
Chuck WB2EDV ----- Original Message ----- From: "Adam Feuer" <[email protected]> To: <[email protected]> Sent: Monday, November 23, 2009 6:27 PM Subject: [Repeater-Builder] UHF Mastr II PA - SLOW > Hello All, > > I have on the bench into a dummy load an exceptionally clean Mastr II > 100 watt UHF PA. It appears to be a "late model" version because it has > the Z-Match board right above the RF output connector. > > At 13.6 volts and 21 amps, it's doing 100 watts easily. I can vary it > down all the way and vary it up to about 128 watts. So, to me it seems > like it's in good shape. I left it key'd for 30 minutes and the current > and power output stayed the same, 21 amps and 100 watts. > > After letting it cool, I key'd it up again. It immediately went up to > only 20 watts, then after about 30 seconds it hit 75 watts and finally > after close to a minute and a half, it hit 100 watts. I let it cool > again, and same thing. This appears to be the way this amp is as > nothing I can do can get it to change. I checked the exciter and > immediately upon being key'd it puts out 220 mw. > > Any thoughts or suggestions would be greatly appreciated. > > Thanks!! > > Adam N2ACF > > > ------------------------------------ > > > > Yahoo! Groups Links > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.709 / Virus Database: 270.14.79/2522 - Release Date: 11/23/09 14:45:00
