Sounds like the classic Astron "cold solder joint on one of the output transistors" problem. Many an Astron has suffered from this....... or maybe only able to supply about 5 amps (50 amp supply) before it crashes.
Be sure to check the buss wires connecting all 8 of the collectors of the output transistors. While the supply is powered down grab each connecting buss wire with a pair of pliers right near the collector connection. Tug on each one to see if any of them "break lose". All it takes is for one of the 8 connections to be bad.....when it does, the Base to Emitter junction of that transistor becomes forward biased and the main Driver transistor then becomes the primary current source element for the whole supply and the rest of the 7 transistors are doing nothing to hold up their end of the load sharing. If you do have one transistor with a solder problem, what you are probably experiencing is a quick "in-rush" of current when your small radios first have power applied. This in-rush current probably exceeds the capability of the driver transistor, the current sensing circuitry, and the unit goes into over current protection by shutting down. Ron Rogers WW8RR -----Original Message----- From: Daron J. Wilson [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 14, 2004 4:12 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Astron Over Voltage or Crowbar issues I've read the description on the repeater builder website of the astron issues and circuits, but not sure if that will solve what I'm currently experiencing. I've got a 50 amp rack mount supply, the problem with them is that if there is much of a load or draw on them when you DO restore AC power, they go into this protect mode. I've got a couple small radios on them, but when power comes on there is an immediate current draw and that seems to lock the power supply down. The only way I have found to get it back is to turn it off, disconnect the load, plug it in, then hook the load back up. Is it all the same issue and will the overvotage circuit solve that as well? Thanks in advance, Daron J. Wilson, RCDD ) ) Telecom Manager ( ( LH Morris Electric, Inc. ) ) (541) 265-8067 office _|****| mmm! (541) 265-7652 fax ( | | coffee! (541) 270-5886 cellular \| | [EMAIL PROTECTED] |____| Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
