I really have kept an eye onLemon$ He is very smart but loves to say on just repeated specs and letting you know where to get a service manual. I think he is a brainwashed head by the big "M". do what i said or buy a $250 Switcher, That simple! or make your life miserable tryin to fix the thing. Hey $250 might be a lot of beans, butt beats a(a) 1500 to replace that astron peixe of crap! USU SAMLEXbeats payin a grand or more!!!!!! oh yeay, can see this comin, locked and loaded verbally! Bring it Lemmon. you are not ready for my experience!!!!!!!! Not even close to my age, so would love fot you to bring it on, Smart A..
--- On Sun, 6/20/10, Eric Lemmon <wb6...@verizon.net> wrote: From: Eric Lemmon <wb6...@verizon.net> Subject: RE: [Repeater-Builder] Astron RS50 Power Supply To: Repeater-Builder@yahoogroups.com Date: Sunday, June 20, 2010, 8:07 PM Leroy, The problem is that the jumper wire or PCB trace- if it exists- will create a common and low-impedance connection between the AC and the DC sources in a station. This may not cause a problem for some systems, but is certainly not a recommended practice where DC power returns and signal common conductors are at similar potentials. It is a long-established practice in the power, broadcast, and communications industries that there should be only one connection where all signal and power grounds are brought together. For residential and commercial wiring, the National Electrical Code (NFPA 70) calls this point "the service." The Code is very explicit that the service is where CATV coaxial shields, telephone line protectors, and the power neutral are joined. Likewise, most cellular and LMR stations follow such guidelines as the Motorola R56 Manual, which specifies a "ground window" where station grounds, power grounds, and feedline grounds are made common. To establish additional grounds at DC power supply returns is almost certain to create "ground loops" that will interfere with sensitive equipment and circuits. A case in point: My 6m repeater controller would lock up periodically, requiring a 60-mile round trip to the mountaintop site to reset the system. When these lockups occurred, both the primary receiver and the link receiver were deaf, and I lost control of the repeater. The cause was not apparent, since the lockups occurred in clear, mild weather with no obvious causes. On a hunch, I tested the Astron RS-35M power supply and discovered that the negative output terminal was jumpered to the chassis. I removed that jumper, and the problem went away-forever. My guess is that a surge from a nearby air-conditioning system was coupled into the grounding system, and the resulting spike on the DC return for the controller caused it to be corrupted. Another repeater that used an Astron power supply had a low-level 60 Hz hum on the audio that was audible only at base stations, which used larger speakers than portables or mobiles. After I did some head-scratching, I surmised that the hum was not a ripple from the power supply, since that would be 120 Hz in a power supply with a full-wave rectifier. This repeater had a gel-cell battery floating on the power supply output (with a Schottky blocking diode, of course), and I noticed that the hum stayed when I turned off the power supply. However, the hum went away when I unplugged the power supply. Aha! Once I removed the internal jumper connecting the negative terminal lug to the chassis, all was well. Astron is not consistent with these jumpers; some models of power supplies- both linear and switching- have them, but not all. IMHO, the station designer should decide where and how the system grounds should be connected, and not the manufacturer of a power supply. 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Leroy A. M. Baptiste Sent: Sunday, June 20, 2010 3:28 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Astron RS50 Power Supply I must have missed it, but what is the deal of not connecting the negative side of an Astron Supply to case? -----Original Message----- From: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Mike Morris Sent: Sunday, June 20, 2010 6:24 PM To: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> Subject: Re: [Repeater-Builder] Astron RS50 Power Supply At 11:22 AM 06/20/10, you wrote: >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? Did you use the email link on the 404 page to tell the guys at repeater-builder? I just checked the RS50 links and they all seem to work... Let me know which link doesn't work and I'll fix it. You might want to read the repair and modification notes on the "Introductory Information" page. At the least you should add the missing compensation cap and the missing lock washers. Make sure the negative side of the supply is NOT connected to the case. Eric WB6FLY posted a informative note about that a while back. It's reproduced on the "Introductory Information" page. According to the schematic the main diodes in the RS-50 is the 1N1184A. International Rectifier calls it a 40 amp diode. What brand is in your unit? I rebuilt an RS50 a couple of years ago and used a pair of the 1N2129A (60 amp diode). If I were to do it over again I'd use a 100a diode like the 1N3288 that I use in the RS-70. Mike WA6ILQ
