Working on an HMS amp an PA3-2GG-HMS amp right now that I replaced the transistor on the A stage, and the flange resistor on the combiner, and c12 mica cap on the A stage of the amp. All of this was causing only 80 watts out of the amp and no current draw on the A stage of the amp. I put the amp back in place on Tuesday and on Wednesdays I was pulling the amp back into the shop due to a complete failure. This time the flange resistor on the combiner had a blown again, both transistors were bad, and c12 bad arced on the "A" stripe again. I tested swr at the site before and after the the filters and at the antenna side of the polyphaser I see 5 watts with 110 watts forward at the HMS PA I see no SWR or at least so little that I just wiggles the meter needle. When I put the AMP back in-service I was seeing current on both stripes of 15.3 amp + or - .2 amps and the supply voltage was at 21.0 volts with 375watt out of the amp. Any idea what is causing this problem I currently rebuilding this amp again and don't what to blow it again. Gary
_____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Friday, October 19, 2007 1:46 PM To: [email protected] Subject: [Repeater-Builder] Re: TPL amplifier - aka repeater operation at the 250 watt power level > Does anyone have any experience with the TPL 250 watt > 2-meter amps for repeater use? Yep... > (bugs, reliability, operating manual/schematic availability). > steve > WA4BVO Bugs - none Reliability - good Operating Manual - Normally supplied with unit at the time of sale. Schematic Availablity - Included within the manual although I have a number of TPL Amplifier Manuals available for free download off the www.radiowrench.com/sonic web page. A phone call to TPL with a valid credit card in hand always seems to produce results if you must have the exact manual for your specific amplifier. TPL-Amplifiers are about as generic as they come... repair is not a big deal if you're used to working with modest - moderate power rf stages. **** Sidebar: An increase to this relative higher power output level can be a cautious road to travel. A circulator and/or trouble control detection circuit is pretty much a must have. Little problems normally not an issue at operation below the 60/80 watt power level can quickly lead to an equipment melt down. There is very little fudge factor and always no free lunch with 250 Watt operation at/near 146 MHz. cheers, s.
