Re: [Drakelist] R-4A PTO
Dear OMs on this thread, (Do not try to visualize this) Here is my report I promised yesterday: While I was checking cold solder joints, I checked the conductance of the tuning coil. The tap in the middle was fine, but the wire was broken near the rear-end terminal. The meter would jump a little and then show the infinite R. So I think it was a very fine "crack". Here is a picture that shows what it looked like after I de-soldered the PCB from the terminal and lifted the broken end. I soldered it back and now the PTO works fine. Thanks for useful tips. http://kihwal.fayoly.net/ham/pto_broken_wire.jpg Kihwal, K9SUL (ex-HL1SUL) - Original Message - From: Kihwal Lee To: "k4...@mindspring.com" ; drakelist Cc: Sent: Monday, May 9, 2011 12:46 PM Subject: Re: [Drakelist] R-4A PTO Hi Garey, Thanks for the wonderful tips. I will let the list know what I find. I know of a person who redesigned the TR-4 PTO circuit to get the better stability. I do not know what effect it had on the linearity though. I will ask him whether he is okay with sharing the information. 73, Kihwal, K9SUL (ex-HL1SUL) - Original Message - From: Garey Barrell To: drakelist Cc: Sent: Monday, May 9, 2011 12:25 PM Subject: Re: [Drakelist] R-4A PTO Kiwahl - First, that's a 2N3858 in the Buffer position, a 2N3904 will replace. The 2N706 is still available from Mouser and others. Other transistors 'may' work, but 'may' also corrupt the linearity. I don't know. I've been looking for a defunct PTO to conduct these sorts of experiments on, and can't bring myself to mess up a working unit! :-) There are several other, more likely, causes of PTO failure. Top of the list is bad solder joints, particularly the tap on the coil. The 10V Zener sometimes shorts. Leaky or shorted Dur-Mica (brown, dog-bone) cap. Leaky or intermittent disc ceramic cap. Roughly in that order! The Buffer should read about 8 VDC on the Collector, 2.5 VDC on the Base, and 1.9 VDC on the Emitter. The Oscillator should read about 9 VDC on the C, 5.6 VDC on the B, and 5 VDC on the E. The Collector reading may be 'anything', depending upon the characteristics of your meter probe. It may kill the oscillations completely. The important reading here is the Base to be about 0.6 V above the Emitter. If this is true, the transistor is almost certainly ok. Let us know what you find!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Kihwal Lee wrote: > The PTO in my R-4A failed a few days ago. I replaced it with a spare I had, > but I still want to fix it as it has better linearity. In case the > transistors are bad, what are the proper substitutes? It has a 2N3058 and a > 2N706. > > Kihwal, K9SUL > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R-4A PTO
Bravo, Kihwal...! ...And congratulations on a job well done. Those Drake PTOs really AREN'T all that intimidating, once you've gotten "...close & personal" with them, as you've just learned. I applaud your dogged determination to resolve your problem there successfully---and for sharing your findings with the rest of us on this Reflector... ~73~ de Eddy VE3CUI - VE3XZ *** - Original Message - From: "Kihwal Lee" To: ; "drakelist" Sent: Tuesday, May 10, 2011 10:31 AM Subject: Re: [Drakelist] R-4A PTO Dear OMs on this thread, (Do not try to visualize this) Here is my report I promised yesterday: While I was checking cold solder joints, I checked the conductance of the tuning coil. The tap in the middle was fine, but the wire was broken near the rear-end terminal. The meter would jump a little and then show the infinite R. So I think it was a very fine "crack". Here is a picture that shows what it looked like after I de-soldered the PCB from the terminal and lifted the broken end. I soldered it back and now the PTO works fine. Thanks for useful tips. http://kihwal.fayoly.net/ham/pto_broken_wire.jpg Kihwal, K9SUL (ex-HL1SUL) - Original Message - From: Kihwal Lee To: "k4...@mindspring.com" ; drakelist Cc: Sent: Monday, May 9, 2011 12:46 PM Subject: Re: [Drakelist] R-4A PTO Hi Garey, Thanks for the wonderful tips. I will let the list know what I find. I know of a person who redesigned the TR-4 PTO circuit to get the better stability. I do not know what effect it had on the linearity though. I will ask him whether he is okay with sharing the information. 73, Kihwal, K9SUL (ex-HL1SUL) - Original Message - From: Garey Barrell To: drakelist Cc: Sent: Monday, May 9, 2011 12:25 PM Subject: Re: [Drakelist] R-4A PTO Kiwahl - First, that's a 2N3858 in the Buffer position, a 2N3904 will replace. The 2N706 is still available from Mouser and others. Other transistors 'may' work, but 'may' also corrupt the linearity. I don't know. I've been looking for a defunct PTO to conduct these sorts of experiments on, and can't bring myself to mess up a working unit! :-) There are several other, more likely, causes of PTO failure. Top of the list is bad solder joints, particularly the tap on the coil. The 10V Zener sometimes shorts. Leaky or shorted Dur-Mica (brown, dog-bone) cap. Leaky or intermittent disc ceramic cap. Roughly in that order! The Buffer should read about 8 VDC on the Collector, 2.5 VDC on the Base, and 1.9 VDC on the Emitter. The Oscillator should read about 9 VDC on the C, 5.6 VDC on the B, and 5 VDC on the E. The Collector reading may be 'anything', depending upon the characteristics of your meter probe. It may kill the oscillations completely. The important reading here is the Base to be about 0.6 V above the Emitter. If this is true, the transistor is almost certainly ok. Let us know what you find!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Kihwal Lee wrote: > The PTO in my R-4A failed a few days ago. I replaced it with a spare I had, but I still want to fix it as it has better linearity. In case the transistors are bad, what are the proper substitutes? It has a 2N3058 and a 2N706. > > Kihwal, K9SUL > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] FS: Unique Drake Service Supplement CDs
Here is the information that Drake left out of their manuals! Unique supplemental service information CDs available for the Drake TR-4, TR-4C/Cw/CwRIT, A, B and C Lines, 2-C / 2-NT and the 2-B receiver. High resolution color photos of the under chassis and individual PC boards of each unit, with all parts identified and keyed to a parts list make it easy to locate any component. No more trying to trace wires through bundles, etc. This information is not available elsewhere and really makes a difference in servicing these units. These CDs are NOT just scans of the original manuals that were included with the equipment when new. High resolution scans of the original manuals ARE on the CDs, along with scans of manuals for associated equipment such as the C-4, FS-4, MN2000, L-4B, W-4, etc. Samples of these pages (at reduced resolution) and purchase information are at . -- 73, Garey - K4OAH Glen Allen, VA ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] ft-950 to Drake L4B
Can anyone tell me how to hookup a yaesu FT-950 to a Drake L4B? The vox connection is the one that I am not sure how to do. Thank you very very much -Karl WA2OVJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] TR4 clipping (N3JQD)
Hello again. I just bought a clean, functioning TR4 and I have an operational question. Once it is tuned for a freq and I begin talking, the person listening reports that my audio is clipping once in a while. I switched mic's and it's the same. Is it possible that by turning up the Xmtr Gain past it's max gain could cause this? Note: If I tune my T4x in the same manner, once I peak the output; turning up the xmit gain doesn't distort or clip. So, I turned down the xmit gain on the TR4 and at max output, it still clips,but no tas much. Any thoughts? Thank you. Bob N3JQD Groupon™ Official Site 1 ridiculously huge coupon a day. Get 50-90% off your city's best! http://thirdpartyoffers.juno.com/TGL3141/4dc9e70a8d52f358b4ast02vuc ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Sticky finish
What is the "dreaded" sticky finish paint I read about concerning Drake rigs? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Sticky finish
The earlier TR-7 line cabinets featured a new durable paint that was to better the epoxy C line finish. Unfortunately, over time, the paint became "sticky." Check out _www.wb4hfn.com_ (http://www.wb4hfn.com) for a solution to this problem. Apparently, Drake recognized the problem and during the mid 7 line production, switched to a new paint that eliminated the problem. Thus today, Drake 7 line equipment is sold in two versions, sticky and non sticky paint. The 7 line was originally offered in a dark gray cabinet finish. The replacement cases that Drake later sold were flat black. Therefore, you'll actually see Drake 7 lines with three different cabinets, the original stick gray paint, the later non stick gray paint and the replacement cabinet, non sticky black paint. 73 Lee WB6SSW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
