Re: [Drakelist] OT a failure mode of solid state electronics
Ron, Vintage radios were made with regular leaded solder so they don't have that problem (unless you repair them with lead free solder.) It's the new rigs that I'm concerned about. Tin whisker growth under surface mount components would be very difficult to detect and remove. So keep your vintage Drake radios operational and you won't be without a rig if the new one fails. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Ron Sent: Monday, October 31, 2011 6:46 PM To: drakelist@zerobeat.net Subject: [Drakelist] OT a failure mode of solid state electronics All, I was tooling around the web and ran into this video and document. For those unfamiliar, the new lead free solder often has a higher tin content and can causes tin whisker growth issues. Who knows when it might strike your beloved solid state or hybrid vintage radio. Maybe we should all return to hollow state :-) http://www.vintage-radio.info/whiskers/ Totally amazing IMO. 73, Ron WD8SBB ___ 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] OT a failure mode of solid state electronics
From what I've been seeing in the basic design of some newer radios on my repair bench, tin whiskers is the LEAST of your worries regarding longevity! One only needs to research the problems of the TS2000 and the IC 746pro to realize there are some real service/design issues out there. Curt KU8L On 11/1/2011 7:47 AM, Bob Spooner wrote: Ron, Vintage radios were made with regular leaded solder so they don't have that problem (unless you repair them with lead free solder.) It's the new rigs that I'm concerned about. Tin whisker growth under surface mount components would be very difficult to detect and remove. So keep your vintage Drake radios operational and you won't be without a rig if the new one fails. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Ron Sent: Monday, October 31, 2011 6:46 PM To: drakelist@zerobeat.net Subject: [Drakelist] OT a failure mode of solid state electronics All, I was tooling around the web and ran into this video and document. For those unfamiliar, the new lead free solder often has a higher tin content and can causes tin whisker growth issues. Who knows when it might strike your beloved solid state or hybrid vintage radio. Maybe we should all return to hollow state :-) http://www.vintage-radio.info/whiskers/ Totally amazing IMO. 73, Ron WD8SBB ___ 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] OT a failure mode of solid state electronics
A consequence of RoHS compliance. The problem has already been documented with N8LP's LP-100 display board (PLED version). Display segments begin failing, one-by-one until the display becomes very difficult to read. Not sure if there's been any recent developments concerning chemical or process improvements to lessen the severity of the "whiskering." I have spools of Kester clean solder, and a spool with 2% silver -- neither of them flow very well. I'm inclined to stay with Kester 44 60/40 solder from this point forward. Paul, W9AC - Original Message - From: "Bob Spooner" To: "'Ron'" ; Sent: Tuesday, November 01, 2011 8:47 AM Subject: Re: [Drakelist] OT a failure mode of solid state electronics Ron, Vintage radios were made with regular leaded solder so they don't have that problem (unless you repair them with lead free solder.) It's the new rigs that I'm concerned about. Tin whisker growth under surface mount components would be very difficult to detect and remove. So keep your vintage Drake radios operational and you won't be without a rig if the new one fails. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Ron Sent: Monday, October 31, 2011 6:46 PM To: drakelist@zerobeat.net Subject: [Drakelist] OT a failure mode of solid state electronics All, I was tooling around the web and ran into this video and document. For those unfamiliar, the new lead free solder often has a higher tin content and can causes tin whisker growth issues. Who knows when it might strike your beloved solid state or hybrid vintage radio. Maybe we should all return to hollow state :-) http://www.vintage-radio.info/whiskers/ Totally amazing IMO. 73, Ron WD8SBB ___ 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] OT a failure mode of solid state electronics
Paul, Both the lead-free solder and especially the silver solder require higher temperatures (maybe high-temperature flux as well?) to create a proper solder joint. This makes soldering without damaging a component or PC board trace more difficult. An ESD soldering iron with temperature control is a necessary tool for RoHS compliant work. But I wouldn't want to try to work on my TR7A without an ESD soldering iron either. For tube gear it isn't a problem. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Paul Christensen Sent: Tuesday, November 01, 2011 9:08 AM To: drakelist@zerobeat.net Subject: Re: [Drakelist] OT a failure mode of solid state electronics A consequence of RoHS compliance. The problem has already been documented with N8LP's LP-100 display board (PLED version). Display segments begin failing, one-by-one until the display becomes very difficult to read. Not sure if there's been any recent developments concerning chemical or process improvements to lessen the severity of the "whiskering." I have spools of Kester clean solder, and a spool with 2% silver -- neither of them flow very well. I'm inclined to stay with Kester 44 60/40 solder from this point forward. Paul, W9AC - Original Message - From: "Bob Spooner" To: "'Ron'" ; Sent: Tuesday, November 01, 2011 8:47 AM Subject: Re: [Drakelist] OT a failure mode of solid state electronics > Ron, > > Vintage radios were made with regular leaded solder so they don't have > that > problem (unless you repair them with lead free solder.) It's the new rigs > that I'm concerned about. Tin whisker growth under surface mount > components > would be very difficult to detect and remove. So keep your vintage Drake > radios operational and you won't be without a rig if the new one fails. > > 73, > Bob AD3K > > -Original Message- > From: drakelist-boun...@zerobeat.net > [mailto:drakelist-boun...@zerobeat.net] > On Behalf Of Ron > Sent: Monday, October 31, 2011 6:46 PM > To: drakelist@zerobeat.net > Subject: [Drakelist] OT a failure mode of solid state electronics > > All, > I was tooling around the web and ran into this video and document. For > those unfamiliar, the new lead free solder often has a higher tin content > and can causes tin whisker growth issues. Who knows when it might strike > your beloved solid state or hybrid vintage radio. Maybe we should all > return to hollow state :-) > > http://www.vintage-radio.info/whiskers/ > > Totally amazing IMO. > > 73, > Ron WD8SBB > > ___ > 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
Re: [Drakelist] OT a failure mode of solid state electronics
Look into a product called ChipQuick. http://www.chipquik.com/ It is a solder alloy with a low melting temperatue. When applied to a normal solder joint, below the normal solder melting temp, it causes the existing solder to also melt at about 150 degrees and stay melted long enough to remove multi-pin devices. The video is a good overview. This stuff is rapidly taking place of regular desodlering equipment in rework situations. Not inexpensive but a little goes a long way. Curt KU8L On 11/1/2011 8:53 AM, Bob Spooner wrote: Paul, Both the lead-free solder and especially the silver solder require higher temperatures (maybe high-temperature flux as well?) to create a proper solder joint. This makes soldering without damaging a component or PC board trace more difficult. An ESD soldering iron with temperature control is a necessary tool for RoHS compliant work. But I wouldn't want to try to work on my TR7A without an ESD soldering iron either. For tube gear it isn't a problem. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Paul Christensen Sent: Tuesday, November 01, 2011 9:08 AM To: drakelist@zerobeat.net Subject: Re: [Drakelist] OT a failure mode of solid state electronics A consequence of RoHS compliance. The problem has already been documented with N8LP's LP-100 display board (PLED version). Display segments begin failing, one-by-one until the display becomes very difficult to read. Not sure if there's been any recent developments concerning chemical or process improvements to lessen the severity of the "whiskering." I have spools of Kester clean solder, and a spool with 2% silver -- neither of them flow very well. I'm inclined to stay with Kester 44 60/40 solder from this point forward. Paul, W9AC - Original Message - From: "Bob Spooner" To: "'Ron'"; Sent: Tuesday, November 01, 2011 8:47 AM Subject: Re: [Drakelist] OT a failure mode of solid state electronics Ron, Vintage radios were made with regular leaded solder so they don't have that problem (unless you repair them with lead free solder.) It's the new rigs that I'm concerned about. Tin whisker growth under surface mount components would be very difficult to detect and remove. So keep your vintage Drake radios operational and you won't be without a rig if the new one fails. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Ron Sent: Monday, October 31, 2011 6:46 PM To: drakelist@zerobeat.net Subject: [Drakelist] OT a failure mode of solid state electronics All, I was tooling around the web and ran into this video and document. For those unfamiliar, the new lead free solder often has a higher tin content and can causes tin whisker growth issues. Who knows when it might strike your beloved solid state or hybrid vintage radio. Maybe we should all return to hollow state :-) http://www.vintage-radio.info/whiskers/ Totally amazing IMO. 73, Ron WD8SBB ___ 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 mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] OT a failure mode of solid state electronics
The tin whisker growing inside the transistor case that NASA discusses in the article is 45 yrs old. It is not just the solder or the new components that have potential to be affected. http://nepp.nasa.gov/whisker/index.html --- On Tue, 11/1/11, Bob Spooner wrote: > From: Bob Spooner > Subject: RE: [Drakelist] OT a failure mode of solid state electronics > To: "'Ron'" , drakelist@zerobeat.net > Date: Tuesday, November 1, 2011, 8:47 AM > Ron, > > Vintage radios were made with regular leaded solder so they > don't have that > problem (unless you repair them with lead free solder.) > It's the new rigs > that I'm concerned about. Tin whisker growth under surface > mount components > would be very difficult to detect and remove. So keep your > vintage Drake > radios operational and you won't be without a rig if the > new one fails. > > 73, > Bob AD3K > > -Original Message- > From: drakelist-boun...@zerobeat.net > [mailto:drakelist-boun...@zerobeat.net] > On Behalf Of Ron > Sent: Monday, October 31, 2011 6:46 PM > To: drakelist@zerobeat.net > Subject: [Drakelist] OT a failure mode of solid state > electronics > > All, > I was tooling around the web and ran into this video and > document. For > those unfamiliar, the new lead free solder often has a > higher tin content > and can causes tin whisker growth > issues. Who knows when it might strike > your beloved solid state or hybrid vintage radio. > Maybe we should all > return to hollow state :-) > > http://www.vintage-radio.info/whiskers/ > > Totally amazing IMO. > > 73, > Ron WD8SBB > > ___ > 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] OT a failure mode of solid state electronics
While this has crept into design of our radios over the past 25 years or so (remember the ICOMs that "forgot they were radios" when the internal battery died?), it has been a part of commercial test equipment for a longer period. Once the custom parts are gone, a dead piece becomes a parts-donor. I'll be sad on the day when my TEK 465B finally dies, but that scope - from the 70's - is chock-a-block full of custom chips that are now made of unobtanium. A day will come when a TEK 465B or an IC 746-Pro in working condition will be come a collectors piece worthy of a healthy price. Steve, W1ES/4 -Original Message- >From: Curt >Sent: Nov 1, 2011 9:59 AM >To: drakelist@zerobeat.net >Subject: Re: [Drakelist] OT a failure mode of solid state electronics > > From what I've been seeing in the basic design of some newer radios on >my repair bench, tin whiskers is the LEAST of your worries regarding >longevity! One only needs to research the problems of the TS2000 and >the IC 746pro to realize there are some real service/design issues out >there. > >Curt >KU8L > > >On 11/1/2011 7:47 AM, Bob Spooner wrote: >> Ron, >> >> Vintage radios were made with regular leaded solder so they don't have that >> problem (unless you repair them with lead free solder.) It's the new rigs >> that I'm concerned about. Tin whisker growth under surface mount components >> would be very difficult to detect and remove. So keep your vintage Drake >> radios operational and you won't be without a rig if the new one fails. >> >> 73, >> Bob AD3K >> >> -Original Message- >> From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] >> On Behalf Of Ron >> Sent: Monday, October 31, 2011 6:46 PM >> To: drakelist@zerobeat.net >> Subject: [Drakelist] OT a failure mode of solid state electronics >> >> All, >> I was tooling around the web and ran into this video and document. For >> those unfamiliar, the new lead free solder often has a higher tin content >> and can causes tin whisker growth issues. Who knows when it might strike >> your beloved solid state or hybrid vintage radio. Maybe we should all >> return to hollow state :-) >> >> http://www.vintage-radio.info/whiskers/ >> >> Totally amazing IMO. >> >> 73, >> Ron WD8SBB >> >> ___ >> 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
Re: [Drakelist] T-4XC PTO chirps
Hi Guys, I have good news to report. I have the PTO back in the T-4XC and it is working fine. It turned out to be the hardened grease in the PTO ball bearings causing the chirp and warbling after all. It didn't seem to be a plausible cause to me for the symptoms I was experiencing. But before I started changing parts out, I decided to clean the ball bearings and the drive screw and it did the trick. AS for the PTO not working after I reinstalled it into the transmitter, it turned out to be an intermitant connection on the center tap of the PTO coil. Gary told me to check it. Visually it looked OK, but when I pressed on the connection, the oscillator came alive on the scope screen. Gary is amazing he can repair radios from thousands of miles away. So I cleaned up the connection and reflowed it. It is back in the T-4XC and working great now. In fact, right after I got everything back together I heard ZK2V on 10 meters running split. A perfect opportunity to test the Transmitter PTO. He was calling for just EU for a while, but when he asked for USA I started calling 3kc up. I got him on the 3rd or 4th call. That's a new one for me. Niue, I think it is an island down in the south Pacific somewhere. Not very difficult for me on the west coast but, stil a good test for the PTO. This was only 15 or 20 minutes ago, he is still there on 28011 if your interested. Anyway that's the end of this adventure. You guys will hear from me again next time I break something. 73, Bob K6GGO Hi Guys, Here is an update on my T-4XC PTO adventure. I eventually removed the PTO from the transmitter and put it in a panavise on my bench, powered it up and listened to it on my TR-7 with a sniffer wire. While monitoring the tone, I tapped on the rod that carries the ferrite slug. It would make the frequency change and stay on the new frequency every time I tapped it. As an experiment, I opened up the R-4C and tapped on the end of the slug shaft on it. On the R-4C, the frequency would change but always return to the original freq. To make a long story short, I found hardened grease in the ball bearing races. I cleaned the ball bearings, races and the drive screw with denatured alcohol. The frequency returns to the same tone now every time I tap it and the warbling is gone when I turn the knob. I was and am convinced I fixed the problem. Here is the part where Murphy rears his ugly head. I put the PTO back together and reinstalled it in the T-4XC and presto!!what? dead silence. I used the PTO to control the R-4C still dead silence. I checked power and ground it looks fine but still, nary an oscillation from the PTO. So I unsoldered the wires and hauled it's sorry a?!%#$ back onto the bench. Powered it up and still nothing. Obviously, I hosed it somehow during the re-install. I looked for a solder problem around the output terminal it looked ok, but there were a couple of strands of wire from the old connection that the solder sucker (me) missed, but they weren't touching anything. Maybe they were touching something when it was installed, I don't know. At any rate, its dead now and I suspect a semiconductor. here are my questions: (about time eh?) I have the diodes in stock but not the FET or the buffer transistor. If I have to make a Digikey (or Mouser) order anyway, maybe I should just shot gun the thing and put in all new parts except the coils. I also have a PTO from a parts rig that has issues. I would like to rebuild it as well. Will I get into problems with tolerance stackups? I suspect that is why there are "select at test" caps in there. Can I replace the coax that goes from the PTO output to the wafer switch with RG-174? (to give myself a small service loop, to make the re-install easier) If it turns out to be a cap, or if I shotgun it, is there a modern replacement for those horseshoe caps? Is there anything special about the temperature compensating caps, like a backwards temp coefficient for bucking freq drift or something? Is there an easy replacement for those? Sorry for the long post about my epic struggle against the evil Murphy. If the 49ers hadn't won, it truly would have been a lost weekend. Thanks as always, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Vol 40, Issue 59
> Message: 1 > Date: Mon, 31 Oct 2011 14:11:50 -0400 > From: Paul Gerhardt > To: drakelist@zerobeat.net > Subject: Re: [Drakelist] T4XB Poor Transmit > Message-ID: > > Content-Type: text/plain; charset=ISO-8859-1 > > Still playing with swapping the power supplies and today got a 'good' > audio report with the AC-3. I noticed that the OA2 dims a bit with > the AC3 but goes dark on transmit with the AC4 (which gave 'bad' audio > report). Does anyone know what the normal 'look' of the OA2 is when > switching into Transmit? > > Next the meter will come out to check the voltages. What are normal > ripple reading on a modern DVM? > OK this page has a good rundown on checking the P/S voltages http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/PowerSupplyTroubleshooting.htm Basically it says: 2V AC or less on the 700V B+ 1VAC or less on the 250V B+ .5V or less on thebias On the original stock AC-3 I am getting LOTS of AC on the 700V DVM is jumping between 3hundred something and 4 hundred something. Old Radio Shack Analog meter pegs on the 1000VAC scale?! Yet Audio still sounds at least OK?! 4VAC on the 250V line .9VAC on the bias line So at least one of the HV Caps is probably bad. The transformer is pretty warm too after a few hours. I can hold my hand on it but after 30 sec or so it is uncomfortably warm maybe 120-130F. This is probably warmer than it should be as the unit is not transmitting. As the AC-4 is receiving Bad Audio reports and the AC-3 is not I think both supplies must be in need of recapping. Well they are both close to 50 years old. Will put the meter on the AC-4 later. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Vol 40, Issue 59
Paul, If the OA2 is going dark on transmit it means the circuit is going out of regulation, so there's probably lots of ripple on what is supposed to be a regulated DC voltage. That could be the source of your bad audio reports. The OA2 is a shunt regulator and will dim with increased current draw, but it shouldn't go out. You could have some dry or leaky electrolytic capacitors and/or some resistors that have changed value. 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Paul Gerhardt Sent: Tuesday, November 01, 2011 4:34 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] Drakelist Digest, Vol 40, Issue 59 > Message: 1 > Date: Mon, 31 Oct 2011 14:11:50 -0400 > From: Paul Gerhardt > To: drakelist@zerobeat.net > Subject: Re: [Drakelist] T4XB Poor Transmit > Message-ID: > > Content-Type: text/plain; charset=ISO-8859-1 > > Still playing with swapping the power supplies and today got a 'good' > audio report with the AC-3. I noticed that the OA2 dims a bit with > the AC3 but goes dark on transmit with the AC4 (which gave 'bad' audio > report). Does anyone know what the normal 'look' of the OA2 is when > switching into Transmit? > > Next the meter will come out to check the voltages. What are normal > ripple reading on a modern DVM? > OK this page has a good rundown on checking the P/S voltages http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/PowerSupplyTroubleshootin g.htm Basically it says: 2V AC or less on the 700V B+ 1VAC or less on the 250V B+ .5V or less on thebias On the original stock AC-3 I am getting LOTS of AC on the 700V DVM is jumping between 3hundred something and 4 hundred something. Old Radio Shack Analog meter pegs on the 1000VAC scale?! Yet Audio still sounds at least OK?! 4VAC on the 250V line .9VAC on the bias line So at least one of the HV Caps is probably bad. The transformer is pretty warm too after a few hours. I can hold my hand on it but after 30 sec or so it is uncomfortably warm maybe 120-130F. This is probably warmer than it should be as the unit is not transmitting. As the AC-4 is receiving Bad Audio reports and the AC-3 is not I think both supplies must be in need of recapping. Well they are both close to 50 years old. Will put the meter on the AC-4 later. ___ 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] Overload
I located a crystal to cover 1 to 1.5 Mhz, below preselector range for my Drake 4A. Some MW stations are tunable down to 1.3 mhz, but there a few very strong broadcasters just under 1.5 Mhz and I hear a lot of static crashing. Is the front end overloading? I realize an AM table radio is only a few dollars, but it is convenient to tune them in on the R4A. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Side Tone Adjustment for TR4CW Possible?
Howdy, I had a 12AV6 tube (V2) go soft and after replacing it the "chirpy" audio for the side tone went away, (no chirp on the transmitted signal, just on my end) but the new side tone pitch is higher than I prefer. Is there an way to adjust the side tone audio to get it down in the 700-750 Hz range? (not volume, but pitch) Thanks, Michael N4MAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R-4B s/n 15533B is done!
Just did the alignment on R-4B 15533B - sounds great! I re-capped this one using the Hayseed Hamfest Re-cap Kit; everything fit as it should and looks great. This one got a bath and sauna, then re-lube, all tubes checked and an alignment. The trimmers for 80m were set to tightest, so re-doing the rf peaking with the slugs level and at the right frequency resolved that issue. There were no other parts to replace on this one and it's a late-enough production that it has all G10 boards in it, so it should outlast me! Amazingly, when teamed up with my T-4XB (also a B-suffix: see, I DO get lucky sometimes!) the transceive alignment was nearly dead-on. C61 required less than 1/4 turn and that was more to prove to myself that it was right on the money from the git-go. The only fly in the ointment with this one was the large rust spot to the right of the PTO in the front corner. This I sanded to remove as much rust as possible and tried something new: Testor's copper-colored model paint. It's a very close match but, of course, the reflectivity is very different from the copper plating. Still, it does look a lot better than the rust spot, and the paint should keep it from rusting any further. I hope to remember to check into the net on Sunday with this new combo. Now to tear into that heavily-modified "B". That one will go up for sale once I'm done with it. Enjoy Those Drakes... Steve Wedge, W1ES/4 To be is to do - Socrates To do is to be - Plato Do be do be do. - Sinatra All my computers have my signature with various pearls of wisdom appended thereto. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
I sometimes have to remind myself: Occam's Razor is my friend. Steve Wedge, W1ES/4 To be is to do - Socrates To do is to be - Plato Do be do be do. - Sinatra All my computers have my signature with various pearls of wisdom appended thereto. From: Robert Fish Sent: Tuesday, November 01, 2011 3:22 PM To: Drakelist@zerobeat.net Subject: Re: [Drakelist] T-4XC PTO chirps Hi Guys, I have good news to report. I have the PTO back in the T-4XC and it is working fine. It turned out to be the hardened grease in the PTO ball bearings causing the chirp and warbling after all. It didn't seem to be a plausible cause to me for the symptoms I was experiencing. But before I started changing parts out, I decided to clean the ball bearings and the drive screw and it did the trick. AS for the PTO not working after I reinstalled it into the transmitter, it turned out to be an intermitant connection on the center tap of the PTO coil. Gary told me to check it. Visually it looked OK, but when I pressed on the connection, the oscillator came alive on the scope screen. Gary is amazing he can repair radios from thousands of miles away. So I cleaned up the connection and reflowed it. It is back in the T-4XC and working great now. In fact, right after I got everything back together I heard ZK2V on 10 meters running split. A perfect opportunity to test the Transmitter PTO. He was calling for just EU for a while, but when he asked for USA I started calling 3kc up. I got him on the 3rd or 4th call. That's a new one for me. Niue, I think it is an island down in the south Pacific somewhere. Not very difficult for me on the west coast but, stil a good test for the PTO. This was only 15 or 20 minutes ago, he is still there on 28011 if your interested. Anyway that's the end of this adventure. You guys will hear from me again next time I break something. 73, Bob K6GGO Hi Guys, Here is an update on my T-4XC PTO adventure. I eventually removed the PTO from the transmitter and put it in a panavise on my bench, powered it up and listened to it on my TR-7 with a sniffer wire. While monitoring the tone, I tapped on the rod that carries the ferrite slug. It would make the frequency change and stay on the new frequency every time I tapped it. As an experiment, I opened up the R-4C and tapped on the end of the slug shaft on it. On the R-4C, the frequency would change but always return to the original freq. To make a long story short, I found hardened grease in the ball bearing races. I cleaned the ball bearings, races and the drive screw with denatured alcohol. The frequency returns to the same tone now every time I tap it and the warbling is gone when I turn the knob. I was and am convinced I fixed the problem. Here is the part where Murphy rears his ugly head. I put the PTO back together and reinstalled it in the T-4XC and presto!!what? dead silence. I used the PTO to control the R-4C still dead silence. I checked power and ground it looks fine but still, nary an oscillation from the PTO. So I unsoldered the wires and hauled it's sorry a?!%#$ back onto the bench. Powered it up and still nothing. Obviously, I hosed it somehow during the re-install. I looked for a solder problem around the output terminal it looked ok, but there were a couple of strands of wire from the old connection that the solder sucker (me) missed, but they weren't touching anything. Maybe they were touching something when it was installed, I don't know. At any rate, its dead now and I suspect a semiconductor. here are my questions: (about time eh?) I have the diodes in stock but not the FET or the buffer transistor. If I have to make a Digikey (or Mouser) order anyway, maybe I should just shot gun the thing and put in all new parts except the coils. I also have a PTO from a parts rig that has issues. I would like to rebuild it as well. Will I get into problems with tolerance stackups? I suspect that is why there are "select at test" caps in there. Can I replace the coax that goes from the PTO output to the wafer switch with RG-174? (to give myself a small service loop, to make the re-install easier) If it turns out to be a cap, or if I shotgun it, is there a modern replacement for those horseshoe caps? Is there anything special about the temperature compensating caps, like a backwards temp coefficient for bucking freq drift or something? Is there an easy replacement for those? Sorry for the long post about my epic struggle against the evil Murphy. If the 49ers hadn't won, it truly would have been a lost weekend. Thanks as always, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobe
Re: [Drakelist] Side Tone Adjustment for TR4CW Possible?
Mike, I think it's an audio phase-shift oscillator, so guess you would need to change some of the R-C values to get a lower freq. Others will give better thoughts I am sure. 73 Mark N5KAE - Original Message > From: Michael A. Kelly > To: drakelist@zerobeat.net > Sent: Tue, November 1, 2011 8:49:00 PM > Subject: [Drakelist] Side Tone Adjustment for TR4CW Possible? > > Howdy, > > I had a 12AV6 tube (V2) go soft and after replacing it the "chirpy" > audio for the side tone went away, (no chirp on the transmitted > signal, just on my end) but the new side tone pitch is higher than I > prefer. Is there an way to adjust the side tone audio to get it down > in the 700-750 Hz range? (not volume, but pitch) > > Thanks, > > Michael N4MAK > > ___ > 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] Overload
Neil, These old Drake rigs are communications rig, not general coverage SW rigs. Drake did make models that are, but not your R4A. There are circuits to deliberately block these "strong AM stations" so that they do not interfere on 160m (1.8 to 2.0) or their images on 80m even. Without defeating the input filtering, you are just stuck with what the Drake designers had to fight, AM interference from strong broadcasters on the lower ham bands. Neil, I mean this in a positive way, so don't take it any other way, but you ask an awful lot of questions and it would be helpful if we know if you are a ham or not, and some about yourself so we have an idea of your level of radio knowledge. That way we don't give dumb answers and can tailor questions better to that level. I am an old, retired educator and always did a better job knowing what my students knew. 73, Don, ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
