"EP Swynar" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Good Morning Gang,
Well, Garey (once again!) earns top honours with his expert long distance trouble-shooting skills...! I poked around the back of switch S1 in my T-4X, & saw that the switch lug that anchors R63 & C132 looked a tad "askew" relative to the rest of the lugs...sure enough, with the aid of a small screwdiver, it was quickly made apparent that that the lug had been broken off of the switch, taking a good chunk of phenolic with it. Peering down into the switch shows that another lug is "askew" as well --- but it doesn't appear to have any phenolic "residue" attached to it (NOT a good thing). I've epoxied these things successfully in the past with an old Heathkit SB-400 transmitter that I owned, but man-o-man, this particular switch is buried REALLY good within the bowels of the T-4X! Oh well, it will simply HAVE to remedied, no question about that...and if the epoxy ends up a "bust", I'm wondering aloud if there might be any source of "donor" switches around --- or is this another one of those rare earth elements commonly referred to as "...Unobtanium"...? Hi Hi. Thanks to all for having taken the time & trouble to come to my aid with your individual diagnosis --- it's all much appreciated! ~73~ Eddy VE3CUI - VE3XZ **************************************** ----- Original Message ----- From: "Garey Barrell" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Saturday, July 05, 2008 10:33 AM Subject: Re: [drakelist] T-4X: No Audio On SSB / AM > Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang > ---------------------------------------------------------------------- > Eddy - > > OK. Well if it works in TUNE, then ALL the audio stages are working > fine. In TUNE, the first mic preamp stage is switched to become a phase > shift audio oscillator, and that tone then goes through the transmitter > just as if you whistled into the microphone. That same tone is used for > the sidetone, and to keep the PTT relay closed in CW. So this leaves a > very narrow field for failures, i.e., a couple of switch contacts or the > mic jack. > > So... Either John is correct that your mic is bad, (D-104's are prone > to failing from heat and/or humidity,) the wiring to the mic jack is > wrong, or there is a problem with the switching between mic amp and TUNE > oscillator. > > You can check the mic with a scope, if you have one, if not, a VTVM or > "good" DMM right at the cartridge terminals should show considerable (a > volt or so) AC output when you whistle into the mic. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs > <www.k4oah.com> > > > > EP Swynar wrote: > > "EP Swynar" <[EMAIL PROTECTED]> made an utterance to the drakelist gang > > ---------------------------------------------------------------------- > > On 4th July, Garey wrote... > > > > "...If you have a KEY plugged in, it must be closed (or unplugged) for > > SSB..." > > > > *************************************** > > > > Hi Garey, > > > > Well, I was HOPING that the solution to my lack of audio on SSB / AM with > > the T-4X would have been that easy, but alas, there was no joy in Muddville > > (again) when I tried it here (double sigh!). > > > > I measured the resistances on both V9 & V10 afterward, & all appears to be > > normal in that regard...next I guess I'll have to measure the actual > > voltages themeselves. > > > > The rig fires up on CW splendidly: it tunes up just as outlined in the > > manual, has a nice side tone, mutes the R-4, etc. etc. Yet, when I switch to > > SSB, I CAN trip the internal relay by pressing the PTT button --- but I get > > only a VERY slight indication of plate current (NO output power) in the > > mode, and no upward kicks of the meter in any position when tapping the > > mic...even with the gain cranked way up. > > > > With the rig set to AM, the plate current DOES swing hard right momentarily > > when the PTT is first keyed, but I suspect that has something to do with the > > controlled carrier set-up in that mode. > > > > Back to the ol' proverbial drawing board for me, I guess...! > > > > ~73~ Eddy VE3CUI - VE3XZ > > > > > > > > ---------------------------------------------------------------------- > Submissions: [email protected] > Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - help in body of message > Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net > ---------------------------------------------------------------------- ---------------------------------------------------------------------- Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
