Re: [Drakelist] Tr7. Audio
On Fri, 11 Sep 2015 09:55:25 -0500, DW. Anderson wrote: >Greetings to the group, thanks to you fixed last issue with the tr7, have new >issue , when I tune the radio in am, go to switch to CW, rtty, ssb lose audio >, meter is showing signals coming in and in transmit showing power out, but to >audio, any thoughts ? Sounds like you are losing the BFO. Since it affects both CW and SSB I would suspect the signal path between pin 40 of the PBT/Ref board and pin 40 of the 2nd IF/Audio board. Probably one of those pesky Molex connectors. Often just pulling the board up and re-seating will clear problems like this, but a little dab of DeOxit on all the pins wouldn't hurt. Don't spray, it will go everywhere that you don't want it. 73 -Jim NU0C -- Theres something out of place lets go and poke it with a stick. The Doctor, "Amys Choice" ___ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 audio oscillation
Harold - I don't recall a ferrite bead fix. Often this sort of problem is the result of leaky T/R transistors (fuses!) Q306 & Q307 on the Transmit/Exciter board allowing BOTH transmit and receive functions to "sorta" work at the same time. Check the 10R and 10T busses on the parent board. Each should read near +10V when it should be "ON", and less than 0.1V when it should be off "OFF". 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs hpolkscw wrote: I have a TR-7, serial, 45XX, that breaks into oscillation on both receive and transmit after some time warming up. However, it sometimes howls from startup. I remember reading some messages some time ago about a fix, which I think was a ferrite bead on a component leg. However, I cannot find this message after much searching, both on my computer and the archives. Can anyone point me in the direction of the message or provide the particulars of the modification. Thanks Harold N3HP ___ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 audio oscillation
Harold, I am not sure if that ferrite core will work in this application, nor can I say I have heard or seen such for an internal problem. With those older TR7's, the ferrite core solution sounds like a bandaid where surgery is required. If I had to venture a guess I would say it sounds more like a board seating issue to the mother board or a loose solder connection on one of the boards that creates the oscillation after the internal temperature rises and cause the boards to shift a little. Ron / WB4HFN - Original Message - From: "hpolkscw" <[EMAIL PROTECTED]> To: [email protected] Sent: Thursday, December 4, 2008 10:02:58 AM GMT -05:00 US/Canada Eastern Subject: [Drakelist] TR7 audio oscillation I have a TR-7, serial, 45XX, that breaks into oscillation on both receive and transmit after some time warming up. However, it sometimes howls from startup. I remember reading some messages some time ago about a fix, which I think was a ferrite bead on a component leg. However, I cannot find this message after much searching, both on my computer and the archives. Can anyone point me in the direction of the message or provide the particulars of the modification. Thanks Harold N3HP ___ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Tr7 Audio
On Tue, 11 Nov 2008 18:35:38 -0500, Rex wrote: > My Drake Tr7 transmit audio sounds hollow and like I'm talking on a telephone > and "boxy". I've tried other Microphones that I know are good and the same > hollow- boxy audio. >Anyone have any suggestions Check this first: http://www.zerobeat.net/drakelist/passband.html 73, -Jim NU0C ___ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
