Re: [drakelist] T-4XC hanging in transmit mode
Doug Smith [EMAIL PROTECTED] made an utterance to the drakelist gang -- OK, the AC-4 rebuild kit is done and installed. (Nice kit, BTW.) The measured voltages before the upgrade: = B+ 683 (0.40 VAC Ripple) Low B+ 278 (0.12 VAC Ripple) Bias-59.5 (0.022 VAC Ripple) The measured voltages AFTER the upgrade: = B+ 675 (0.35 VAC Ripple) Low B+ 275.5 (0.055 VAC Ripple) Bias-59.5 (0.018 VAC Ripple) The ripple on the low B+ circuit is much better but on the B+ and Bias supplies the ripple figure is about the same.. I'm gonna call it a night. Tomorrow I plan to do a complete alignment on both the T-4XC and R-4C. Plus, I'll snoop around in the VOX circuit to see what I can see.. 73, -Doug, W7KF On Sat, 2007-10-27 at 20:09 -0600, Doug Smith wrote: Thanks for the input and I'll report back as soon as I have the AC-4 rebuilt.. -- 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 --
[drakelist] T-4XC hanging in transmit mode
Doug Smith [EMAIL PROTECTED] made an utterance to the drakelist gang -- [I posted on this a while back but am just getting around to it.] My T-4XC has been intermittently hanging in transmit mode on CW. Everything runs along fine but periodically when I stop sending the transmitter doesn't seem to drop out of TX mode and normal bias current is registered on the TX meter. During these episodes there is no RF output (unless I hit the key again then I get normal RF out). If I then send a long string of dits when I stop the T/R function usually resumes normal operation - for a while. Today I pulled the AC-4 out of the MS-4 and measured the various voltages: High B+ 683 VDC with 0.4 VAC ripple Low B+ 278 VDC with 0.12 VAC ripple Bias-59.5 VDC with 0.022 VAC ripple Which all seem a bit high but mostly nominal. The bias range is from -45 to -95. The ripple figures are peak to peak as measured on my 'scope. I poked around underneath the AC-4 and I don't see anything that looks 'wrong'. I was able to reproduce this problem this morning but I am unable to reproduce the problem now that I've fooled around with the AC-4. For the life of me, it *feels* like the T/R relay is simply hanging up when transitioning from transmit to receive. But, I'd rather develop a theory based on something other than what I *feel*.. Does anyone have any suggestions as to what I oughta be looking at? Tnx and 73, -Doug, W7KF -- 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 --
Re: [drakelist] T-4XC hanging in transmit mode
EP Swynar [EMAIL PROTECTED] made an utterance to the drakelist gang -- On 27th October, Doug wrote... ... My T-4XC has been intermittently 'hanging' in transmit mode on CW... * Hi Doug, This may be of no help to you whatsoever, however, for it's worth, some time ago I was using an external relay switching box to activate the T/R relay inside my homebrewed linear amplifier (a pair of 813's) --- the 12 VDC relay inside the box received its control, or on voltage, from the Icom 751A transceiver that was used to excite the amplifier... Anyway, suddenly and without warning one day, the T/R control relay inside the box decides to hang in transmit mode, just like it was activated --- even though in reality, I'd switched from sending, to receiving. The duration of its hang was dependent upon how long a transmission I was making --- if it was a L-O-N-G ...old buzzard-type monolgue, it'd hang forever...until I'd momentarily switch off the exciter's power supply, that is, and then it would release. Anyway, I don't know what precipated this sudden affliction --- re-arrangement of the rigs atop the shack...? The phase of the moon...? --- but I dismantled the T/R relay box, put an ordinary RF choke in series with each of the coil windings to the relay, and bypassed these leads at the entry point of the enclosure with a pair of 0.01-ufd. disc ceramics. Problem solved. Is it possible that, for reasons unknown, RF is maybe somehow getting into the relay control circuitry...? I know it's a stretch, because the rig obviously worked well enough before...but then so did mine here! Hi Good luck, in any event... ~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 --
Re: [drakelist] T-4XC hanging in transmit mode
john [EMAIL PROTECTED] made an utterance to the drakelist gang -- Doug, I seem to remember bias voltage being an issue for this problem Best 73 John k5Mo At 04:52 PM 10/27/2007, Doug Smith wrote: Doug Smith [EMAIL PROTECTED] made an utterance to the drakelist gang -- [I posted on this a while back but am just getting around to it.] My T-4XC has been intermittently hanging in transmit mode on CW. Everything runs along fine but periodically when I stop sending the transmitter doesn't seem to drop out of TX mode and normal bias current is registered on the TX meter. During these episodes there is no RF output (unless I hit the key again then I get normal RF out). If I then send a long string of dits when I stop the T/R function usually resumes normal operation - for a while. Today I pulled the AC-4 out of the MS-4 and measured the various voltages: High B+ 683 VDC with 0.4 VAC ripple Low B+ 278 VDC with 0.12 VAC ripple Bias-59.5 VDC with 0.022 VAC ripple Which all seem a bit high but mostly nominal. The bias range is from -45 to -95. The ripple figures are peak to peak as measured on my 'scope. I poked around underneath the AC-4 and I don't see anything that looks 'wrong'. I was able to reproduce this problem this morning but I am unable to reproduce the problem now that I've fooled around with the AC-4. For the life of me, it *feels* like the T/R relay is simply hanging up when transitioning from transmit to receive. But, I'd rather develop a theory based on something other than what I *feel*.. Does anyone have any suggestions as to what I oughta be looking at? Tnx and 73, -Doug, W7KF -- 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 --
Re: [drakelist] T-4XC hanging in transmit mode
Doug Smith [EMAIL PROTECTED] made an utterance to the drakelist gang -- Wow, I would have thought ripple of .022 VAC (peak to peak) on the -60 VDC bias was pretty clean! Nonetheless, the consensus seems to be bias and/or ripple. I have an AC-4 rebuild kit from Mike at The Heath Kit Shop so I'll drag that out of the box, assemble and install. Thanks for the input and I'll report back as soon as I have the AC-4 rebuilt.. 73, -Doug, W7KF On Sat, 2007-10-27 at 19:22 -0400, Al Parker wrote: Al Parker [EMAIL PROTECTED] made an utterance to the drakelist gang -- I agree, and ripple in particular. 73, Al, W8UT -- 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 --
