Those "older"? units actually have an out of phase tap on the Xfmr, 10v? or somethin! forget what color the leads are, can check. Believe it or not I have brought several of them back to life by just soaking the transformer in varnish and letting it dry of course! That feedback winding oscillates and vibrates the xfmr resulting in non(good) stabilization of the xfmr, vibrates for so long, actually loosen's the windings Now everyone is gonna say i am nuts! For the cost of a can of varnish, think you actually have to use polyurethane today, just try it! beats the cost of a new supply! And of course change all eletrolytics if it is the one wit h a gaint amount of 2N3055 (mpn)or equiv on the outs than i am totally correct! The ic is a national LM723. or just 732? working off old memory here as i now use switchers prob got the schematic for that rig somewhere. used them in a lot of bases in the day, before i got smart enough to swap them out Kevin- On Sun, 6/20/10, James <ka2...@gmail.com> wrote:
From: James <ka2...@gmail.com> Subject: [Repeater-Builder] Astron RS50 Power Supply To: Repeater-Builder@yahoogroups.com Date: Sunday, June 20, 2010, 2:22 PM Hi Guys, I am trying to download a schematic on this site for the RS50M Power Supply and keep getting a 404 Error on each attempt on all the supplies. Any ideas? Also our above mentioned power supply which operates our 2 Meter and 440 Repeaters and a low power link started humming yesterday. A trip to the tower showed that the two large wires coming from the Pass Transistors to the post on top of the regulator board and into the 1000 Uf Electrolytic got so hot it melted the insulation an inch back on the wires, burned an area the size of a quarter on the fiter side of the regulator board, turned the terminal black on the Cap. and cracked the plastic on the cap. It never blew the fuse and a check of the voltage showed it regulating under load and hardly a trace of AC on the 13 volt output. The MOV or eight amp AC fuse never blew. All the equipment hooked to the supply took off and worked well on another supply. Anyone have a guess as to what caused this obvious surge ontop of the cap? I am going to replace the Cap. and one resistor on the regular board which is discolored and hope for the best. Any advise appreciated. Thanks in advance JIM KA2AJH Wellsville, N.Y.
