"Ronald Baker" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Don, before you rewind the transformer, make sure the core half's that fit together are tightly secured around the transformer windings. Both half's are held in place with a tie wraps. I've seen this get a little loose and negative voltage falls back. If this is the problem, taking your figures and squeeze the core half's together, the voltage comes back. If this is the case just tighten the core half's.
Ron Ron Baker / WB4HFN Visit my Website: www.wb4hfn.com Vintage Drake & Collins -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of don Sent: Saturday, August 20, 2005 7:13 PM To: Drakelist; don Subject: [drakelist] tr7 update I got the 3n204 replaced, and put it all back together, and began to get some response. So I thought I would start trying the alignment procedure once again. While adjusting the agc pot to set the s-meter, there was very little change in level, and nowhere enough to correctly cal the s-meter. After checking the schematic, I figured I would check the easiest things first, which in this case there is 4 diodes, 1n4148's three of these had very high resistance, but otherwise good. I changed them out, re-check the agc level, and now have almost too much!! At this point, I realized that as hacked-up as this radio is, I really should start at the begining. I check the PS7, voltage, ripple, all was great, couldn't be better. I then go to the power regulator board. what a mess!!! I removed several diy mods, replaced caps with ones of the correct values, etc. Now, all voltages and pb voltage adjustments off this board are good, EXCEPT, the neg 5v. I think there is a couple of shorted windings on the small pcb transformer, and about the best voltage I get from it is about -3.4, but only when the 10v pot is set to well over 10.75v, not good. The radio will begin to receive with 10v set correctly, but I only have -3v, any lower and the digtial stops, and no audio. and I doubt the alignment will ever be correct at such a low voltage. back now to scratching my head, and trying to figure out a way to fix, hopefully with re-winding the transformer, or having to replace the board. Don KB5GNH ________________________________ avast! Antivirus <http://www.avast.com> : Outbound message clean. Virus Database (VPS): 0533-5, 08/20/2005 Tested on: 8/20/2005 6:13:17 PM avast! - copyright (c) 1988-2004 ALWIL Software. ---------------------------------------------------------------------- On Behalf of "Ronald Baker" <[EMAIL PROTECTED]> Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ ----------------------------------------------------------------------
