20070625.ba v04_n062.bam.20070625 >From ???@??? Mon Jun 25 08:12:41 2007 -0500 Date: Mon, 25 Jun 2007 13:11:34 GMT From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4062 Message-Id: <20070625131137.435EA47010A@srvr1.theporch.com> BOATANCHORS Digest 4062 Topics covered in this issue include: 1) KFS Testing on 17026kc by Richard Dillman 2) Re QST Scan request by "JAMES HANLON" 3) Solid State Rectifier Repalcement For 51J Radios & Others by "Thomas Frobase" 4) Where was "Waldo"? by listown@nanniandjack.com (Mail List Owner) 5) Re: KFS Testing on 17026kc by "Al Parker" 6) RE: KFS Testing on 17026kc by "Ed Zeranski" 7) Re: Solid State Rectifier Repalcement For 51J Radios & Others by "Arden Allen" 8) unsubscribe by "Nancy" 9) RE: Solid State Rectifier Repalcement For 51J Radios & Others by "Thomas Frobase" 10) Want to Save 500kc? Here's how! by Richard Dillman 11) Re: Solid State Rectifier Repalcement For 51J Radios & Others by "Arden Allen" 12) Re: Solid State Rectifier Repalcement For 51J Radios & Others by "Tom Rauch" 13) Re: Want to Save 500kc? Here's how! by "Tom Rauch" 14) Re: Solid State Rectifier Repalcement For 51J Radios & Others by wb3fau@att.net 15) Re: Solid State Rectifier Repalcement For 51J Radios & Others by "Tom Rauch" 16) Re: Solid State Rectifier Repalcement For 51J Radios & Others by wb3fau@att.net 17) Re: Want to Save 500kc? Here's how! by Richard Dillman 18) Re: Solid State Rectifier Repalcement For 51J Radios & Others by john 19) Re: Solid State Rectifier Repalcement For 51J Radios & Others by Scott Robinson 20) Looking for HP 5425L schematic by Charles 21) Re: Want to Save 500kc? Here's how! by stuck in 50s 22) Re: Looking for HP 5425L schematic by "John Gillespie" ---------------------------------------------------------------------- Message-ID: <6800387.1182629260021.JavaMail.root@mswamui-valley.atl.sa.earthlink.net> Date: Sat, 23 Jun 2007 20:07:40 +0000 (GMT+00:00) From: Richard Dillman To: Old Tube Radios Subject: KFS Testing on 17026kc Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Please correct: >KFS is on the air as usual running a wheel with the traffic list >scheduled for 2100 GMT and high seas weather at 2130 GMT on: to read: KSM is on the air as usual running a wheel with the traffic list scheduled for 2100 GMT and high seas weather at 2130 GMT on: Thanks, RD ------------------------------ Message-ID: From: "JAMES HANLON" To: Old Tube Radios Cc: "Ray Osterwald" <1editor2@indra.com>, "johnmb" Subject: Re QST Scan request Date: Sat, 23 Jun 2007 14:14:33 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0444_01C7B5A0.D2BE4C30" This is a multi-part message in MIME format. ------=_NextPart_000_0444_01C7B5A0.D2BE4C30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Y'all, John, K5MO, supplied me with the November 1939 QST scan that I needed. = Thanks, John, and please don't anyone else send me one. Boatanchors folks are GREAT! Jim, W8KGI ------=_NextPart_000_0444_01C7B5A0.D2BE4C30 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0444_01C7B5A0.D2BE4C30-- ------------------------------ From: "Thomas Frobase" To: Old Tube Radios Subject: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sat, 23 Jun 2007 15:30:21 -0500 Message-ID: <057601c7b5d5$53aa4e00$0c01010a@tfrobase1> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Based on comments from this and the Collins forum, I have prototyped and am in the process of putting some kits together for rectifier replacements. My principle approach was toy make this for Collins 51J gear but it should work in most anything. I have placed a white paper explanation at http://www.kitparts.com/51J-Collins/ Thanks tom ... N3LLL ------------------------------ From: listown@nanniandjack.com (Mail List Owner) To: Old Tube Radios Subject: Where was "Waldo"? Date: Sat, 23 Jun 2007 14:19:28 -0700 (PDT) Message-Id: <20070623211928.C32CB14133@osr506.nanniandjack.com> Hey Gang- Just thought I would remind folks of how much I enjoy the BoatAnchors list and the fine folks who share their experience and expertise here... On my tour of 13 states I had the extreme pleasure of meeting Mike W0WG and Steve WA9JML -- two very interesting gentlemen and both a joy to talk with. You two made a long day into a real pleasure cruise! The mobile is parked for the moment, but you can find "Waldo" at: http://www.findu.com/cgi-bin/find.cgi?call=w4kh-2 Poor car just isn't big enough to carry a fire bottle 2-meter CB, and certainly neither carry capacity nor room for a fire bottle computer and GPS receiver! Oh well... ;) Still here and still watching... y'all be cool! -- 73 Jack, W4KH/Mobile - - - Mailing List Archiver/Owner - - - listown@nanniandjack.com - "Plus ca change, plus c'est la meme chose" "Il n'y a que les idiots qui ne changent jamais d'idee" ------------------------------ Message-ID: <031e01c7b5e1$50a5a310$6401a8c0@reloaded> From: "Al Parker" To: Old Tube Radios Subject: Re: KFS Testing on 17026kc Date: Sat, 23 Jun 2007 17:56:12 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original Content-Transfer-Encoding: 7bit copied 559 - 579 QSB at 1250Z on Mackay Marine 3021A & 80/40m trap dipole East Coast, 30 mi. from the Atlantic 73, Al, W8UT New Bern, NC www.boatanchors.org www.hammarlund.info ----- Original Message ----- From: "Richard Dillman" To: "Old Tube Radios" Sent: Saturday, June 23, 2007 4:07 PM Subject: KFS Testing on 17026kc > > Please correct: > >>KFS is on the air as usual running a wheel with the traffic list >> >scheduled for 2100 GMT and high seas weather at 2130 GMT on: > > to read: > > KSM is on the air as usual running a wheel with the traffic list scheduled > for 2100 GMT and high seas weather at 2130 GMT on: > > Thanks, > > RD ------------------------------ From: "Ed Zeranski" To: Old Tube Radios Subject: RE: KFS Testing on 17026kc Date: Sat, 23 Jun 2007 15:55:45 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Dickie D! Will fly back to the good old USofA tomorrow so will listen. Since I = last saw you, last year?????, I picked up a RYCOM selective voltmeter = that will be part of the 600 meter/500kc ear suite. Next weekend there = will be a 'Radio Ramble' to Sacremento to pick up the WWII generator for = the SCR-624 station I bought from Tom. So...give him a heads up that = I'll try to contact him to pick stuff up. Please cc my other email: = KG6UTS@AMSAT.ORG EdZ ....... now back in safe Mainz GE where at midnight a Fest is going = outside my window with beer and bra punishing women. In preparation for Night of Nights (12 July) KFS/A is testing on = 17026kc, ------------------------------ Message-ID: <002001c7b5f8$c43b0e70$5e9f480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sat, 23 Jun 2007 17:43:57 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > I have placed a white paper explanation at > http://www.kitparts.com/51J-Collins/ OK, Tom, not a bad idea for a prototype, a semi-smart digital age 5Y3GT imitator. The problem I have with it is you haven't applied the Mad Man Muntz rigor to the design. It has too many parts. Also a lifetime reliability problem. My thoughts are along the line of pulse-width modulating a single high voltage MOSFET (no relays) in series with the rectifier cathode(s) to control turn-on surge after the warmup delay. I don't like relay contact burn-out. Also, when replacing a vacuum tube rectifier with silicon diodes the "plate resistance" goes to virtual zero. All that's left is the high voltage winding's resistance. Depending on the radio's filter circuit that can mean somewhat higher B+ voltage. That's not an easy one to solve with a plug-in only replacement. It means adding a power resistor into the chassis, assuming space available, where the heat is not a problem. Continuous pulse-width modulation is out of the question because of noise concerns. It needs to be fully insulated also. My comments from the peanut engineering galary... Arden Allen KB6NAX ------------------------------ Message-ID: <001e01c7b5fb$4fe3dae0$6501a8c0@connie> From: "Nancy" To: Old Tube Radios Subject: unsubscribe Date: Sat, 23 Jun 2007 20:02:15 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Please take us off your list. ------------------------------ From: "Thomas Frobase" To: Old Tube Radios Subject: RE: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sat, 23 Jun 2007 20:08:14 -0500 Message-ID: <001001c7b5fc$25c32300$0c01010a@tfrobase1> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Works fine on a swinging choke input about 15 extra volts which I believe is acceptable. For the cap input Radios I was thinking of using a zero crossing detector and a pair of SCR's steal a couple of alternations here and there and drop the voltage by 10%, add a ground wire (requires modification of one wire to an unused pin on the rectifier) and you have a B+ regulation circuit. No noise because you are switching at zero volts. I did a lot of temperature controllers using this technique back in the 70's. I megged out the relays to 2000 volts, with no leakage. Will they hold up for 50 years, probably not, but the relay only runs when the radio is turned on. The second relay is only enguaged on startup. As for Muntz, there ain't much there and what is, is accessible. As for my personal experience with Muntz, less was not better because they could not be maintained! Yes, on the insulation, the stupidity factor reins! -----Original Message----- From: Arden Allen [mailto:gumbear@pacbell.net] Sent: Saturday, June 23, 2007 7:44 PM To: tfrobase@kitparts.com; Old Tube Radios Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others > I have placed a white paper explanation at > http://www.kitparts.com/51J-Collins/ OK, Tom, not a bad idea for a prototype, a semi-smart digital age 5Y3GT imitator. The problem I have with it is you haven't applied the Mad Man Muntz rigor to the design. It has too many parts. Also a lifetime reliability problem. My thoughts are along the line of pulse-width modulating a single high voltage MOSFET (no relays) in series with the rectifier cathode(s) to control turn-on surge after the warmup delay. I don't like relay contact burn-out. Also, when replacing a vacuum tube rectifier with silicon diodes the "plate resistance" goes to virtual zero. All that's left is the high voltage winding's resistance. Depending on the radio's filter circuit that can mean somewhat higher B+ voltage. That's not an easy one to solve with a plug-in only replacement. It means adding a power resistor into the chassis, assuming space available, where the heat is not a problem. Continuous pulse-width modulation is out of the question because of noise concerns. It needs to be fully insulated also. My comments from the peanut engineering galary... Arden Allen KB6NAX ------------------------------ Message-ID: <19249615.1182650258351.JavaMail.root@mswamui-cedar.atl.sa.earthlink.net> Date: Sat, 23 Jun 2007 18:57:38 -0700 (GMT-07:00) From: Richard Dillman To: Old Tube Radios Subject: Want to Save 500kc? Here's how! Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit For those in the USA who want to preserve 500kc for commercial Morse operation, there's a relatively simple way to do it: License your own class 1A common carrier commercial coast station. I know that sounds like a tall order. But as we found when applying for the KSM license it really is not. You no longer have to show financial viability, file tariffs, maintain certain hours of operation or indicate what type accepted transmitters you will use. You simply have to select the right frequencies, check the right boxes on Federal Communications Commission form 601 and pay the filing fee. All of this can be done on line. If all goes well the result will be a license with a 10 year term and a three letter call. We formed a non-profit corporation to apply for the license but that's not strictly necessary. You can apply as an association or as an individual. The trick is to cause the FCC as little trouble as possible in processing the form. All the Morse frequencies are still in the Rules. As long as you select carefully you should have little problem. My suggestion is to apply for a MF authorization first. Choose 500kc (of course) and a working frequency. If the working frequencies in your part of the country are shown as licensed to a coast station (like WCC, WLO, WSC, etc.) a letter of agreement can usually be obtained from the licensee permitting you to use that frequency on a non-interference basis. That's what we did to license 426kc which is also licensed to KPH. Interference will not be a problem since those stations no longer use MF even though they are still licensed for it. The objective is to get the basic license. Once you have the authorization in hand you can apply for additional things such as HF frequencies (even those not in the Morse table of frequencies), RTTY, etc. Or simply stay on MF, as many smaller stations did in the golden age. But the main thing is to obtain an authorization for commercial use of MF. For as long as your license is in effect you will have authority to use those frequencies whenever you wish (just mind the silent period!). If anyone is seriously interested in doing this I would be happy to provide help and guidance. But do it now before the provisions that permit such licenses disappear from the books! I look forward to hearing new stations on MF for Night of Nights 2008. A side benefit of saving 500kc for commercial Morse by obtaining your own coast station license will be the preservation of the Radiotelegraph ticket - and the creation of a path to the coveted First Class Radiotelegraph license. A minimum of a Second Class Radiotelegraph license is required to be an operator at a commercial Morse coast station. I suspect many members of this list already have that ticket, or could easily pass the test to obtain one. Ah, but to sit the exam for the First Class Radiotelegraph license one must be able to demonstrate experience as a commercial Morse operator aboard ship or at a coast station. The places where such experience can be obtained are indeed thin upon the ground these days. As the US Federal Communications Commission recently ruled, amateur and military experience doesn't count. But one year after obtaining your coast station license and putting your station into operation, or by being associated with the station of another licensee, you will be qualified to take the exam for the First Radiotelegraph. So it's a winning situation all around. You'll help preserve 500kc for commercial Morse, preserve the existence of the Second Class Radiotelegraph License and become one of the elite holders of the top license, the First Class Radiotelegraph. Once again, I suggest you do it now before the opportunity to apply for these licenses disappears. VY 73, Richard Dillman Chief Operator, KSM ------------------------------ Message-ID: <000b01c7b624$60382a80$47a0480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sat, 23 Jun 2007 22:56:08 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Let me offer some additional comments, Tom: > Works fine on a swinging choke input about 15 extra volts witch I believe is > acceptable. That can be as much as a 5-10% increase in B+ which could be problematic for bias voltages in some designs. Keep in mind a replacement should be a good mirror if it is going to be applied by the mis- or marginally informed user. If it's not it should be marketed with full explanatory notes as to its possible effect on voltage supplies. > For the cap input Radios I was thinking of using a zero crossing detector > and a pair of SCR's steal a couple of alternations here and there and drop > the voltage by 10%, add a ground wire (requires modification of one wire to > an unused pin on the rectifier) and you have a B+ regulation circuit. The voltage variations rate will be in the neighborhood of filter cutoff frequency in many power supplies causing B+ to pump up and down. That would be problematic in unregulated receivers. > No noise because you are switching at zero volts. I did a lot of > temperature controllers using this technique back in the 70's. The integration time of a temperature controller is somewhat longer than rectified AC period. A heavily noise filtered phase control regulator would be better but wouldn't fit inside a 5Y3GT envelope. > I megged out the relays to 2000 volts, with no leakage. Will they hold up > for 50 years, probably not, but the relay only runs when the radio is turned > on. The second relay is only enguaged on startup. On turnoff there will be arcing across the relay contacts. A snubber across the contacts would help. > As for Muntz, there ain't much there and what is accessible. As for my > personal experience with Muntz, less was not better because they could not > be maintained! I would agree. They barely functioned new off the production line ;-) > Yes, on the insulation, the stupidity factor reins! Or simple ignorance. Not nice to have to pay with your life to learn a safety lesson. Arden Allen KB6NAX ------------------------------ Message-ID: <016e01c7b64d$49c6a280$640fa8c0@radioroom> From: "Tom Rauch" To: Old Tube Radios Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sun, 24 Jun 2007 06:48:57 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit > The voltage variations rate will be in the neighborhood of > filter cutoff > frequency in many power supplies causing B+ to pump up and > down. That would > be problematic in unregulated receivers. That's an important point. Make no mistake about it, this would be adding a very low frequency waveform to the B+ line. Dropping enough cycles to lower the voltage requires the power supply filter system have enough energy storage to not vary over that very low rate. In other words the supply has to integrate and/or smooth that very low frequency modulation without having the B plus waddle. Also the ratio of peak to average current would increase, it would be like having a little bit of that turn-on surge happening at the end of every misfire. Thump thump. This is a lot of "stuff" to go through to save 3 to5 watts of heat. Out of 50-80 watts of heat I think it would be like peeing into the wind. A much simpler solution is to just reduce the mains voltage through an autotransformer. Now we don't add a low frequency component, the filaments can all run cooler, and we eliminate the same amount of heat. 73 Tom ------------------------------ Message-ID: <018a01c7b64e$420ea9b0$640fa8c0@radioroom> From: "Tom Rauch" To: Old Tube Radios Subject: Re: Want to Save 500kc? Here's how! Date: Sun, 24 Jun 2007 06:55:55 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original Content-Transfer-Encoding: 7bit > For those in the USA who want to preserve 500kc for > commercial Morse operation, there's a relatively simple > way to do it: > > License your own class 1A common carrier commercial coast > station. So that means I can use my 318 foot insulated base tower near Macon GA as a vertical? What is the power limit? ------------------------------ From: wb3fau@att.net To: Old Tube Radios Cc: "Arden Allen" Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sun, 24 Jun 2007 12:42:06 +0000 Message-Id: <062420071242.27876.467E669E0003B7D600006CE421602806519A0E00CC0D99@att.net> I hear ya Arden. Yes i think some of us have built diode stack replacements for rectifier tubes. My favorite involves replacing those pesky 866 and 816 mercury vapor rectifiers in a Globe King 500. Where i used 4 diodes in series in each line paralleled by .o1 uf caps and 100k resistors. [By the way, mission accomplished for far less than $45!] Russ. ------------------------------ Message-ID: <01a201c7b65e$26830410$640fa8c0@radioroom> From: "Tom Rauch" To: Old Tube Radios Cc: "Arden Allen" Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sun, 24 Jun 2007 08:49:32 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit >I hear ya Arden. Yes i think some of us have built >diode stack replacements for > rectifier tubes. My favorite involves replacing those > pesky 866 and 816 mercury vapor > rectifiers in a Globe King 500. Where i used 4 diodes > in series in each line paralleled > by .o1 uf caps and 100k resistors. [By the way, mission > accomplished for far less than > $45!] Russ. Hi Russ, Do you know of a source for cheap reliable 100K resistors that are rated at 1000V or more? All the resistors I find have a voltage rating of only a few hundred volts, unless I buy some expensive specials. Since it's always been pretty tough for me to find resistors rated at the diode PRV or higher, so I just don't bother with them. 73 Tom ------------------------------ From: wb3fau@att.net To: Old Tube Radios Cc: "Arden Allen" Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Date: Sun, 24 Jun 2007 12:55:40 +0000 Message-Id: <062420071255.6690.467E69CC00036B1A00001A2221602806519A0E00CC0D99@att.net> I guess you mean film resistors? I did not know they had a voltage rating. I use carbon resistors, may not be a problem. Voltage accross each is less than 1000volts in my application. Russ. ------------------------------ Message-ID: <1213173.1182700502018.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> Date: Sun, 24 Jun 2007 08:55:02 -0700 (GMT-07:00) From: Richard Dillman To: Old Tube Radios Subject: Re: Want to Save 500kc? Here's how! Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit >So that means I can use my 318 foot insulated base tower >near Macon GA as a vertical? Heck, yeah! That would be ideal. >What is the power limit? 40kW. For KSM I licensed our MF channels for 5kW. RD ================================= Richard Dillman, W6AWO Maritime Radio Historical Society http://www.radiomarine.org Collector of Harleys, Willys and Radios over 100lbs. ================================= ------------------------------ Message-Id: <6.2.1.2.2.20070624150542.0305db50@pop-server.nc.rr.com> Date: Sun, 24 Jun 2007 15:06:14 -0400 To: Old Tube Radios From: john Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Cc: Arden Allen Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Tom KOA RCR series are pretty stout/ http://www.koaspeer.com/resistors.asp?part=49 John K5MO At 08:49 AM 6/24/2007, Tom Rauch wrote: >>I hear ya Arden. Yes i think some of us have built diode stack >>replacements for >>rectifier tubes. My favorite involves replacing those pesky 866 and >>816 mercury vapor >>rectifiers in a Globe King 500. Where i used 4 diodes in series in >>each line paralleled >>by .o1 uf caps and 100k resistors. [By the way, mission >>accomplished for far less than >>$45!] Russ. > >Hi Russ, > >Do you know of a source for cheap reliable 100K resistors that are rated >at 1000V or more? All the resistors I find have a voltage rating of only a >few hundred volts, unless I buy some expensive specials. > >Since it's always been pretty tough for me to find resistors rated at the >diode PRV or higher, so I just don't bother with them. > >73 Tom ------------------------------ Mime-Version: 1.0 Message-Id: Date: Sun, 24 Jun 2007 17:41:47 -0700 To: Old Tube Radios From: Scott Robinson Subject: Re: Solid State Rectifier Repalcement For 51J Radios & Others Cc: "Arden Allen" Content-Type: text/plain; charset="us-ascii" ; format="flowed" At 8:49 AM -0400 6/24/07, Tom Rauch wrote: > > >Do you know of a source for cheap reliable 100K resistors that are >rated at 1000V or more? All the resistors I find have a voltage >rating of only a few hundred volts, unless I buy some expensive >specials. adn Scott comments: Sure: 1/4 w. resistors are rated for 250V, so put 4 x 25K in series for each 100K 1kV resistor needed. It's a nuisance, but the cost is trivial. Regards. Scott ------------------------------ From: Charles To: Old Tube Radios Subject: Looking for HP 5425L schematic Date: Mon, 25 Jun 2007 07:43:34 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I have acquired an inexpensive HP 5245L counter in nice condition - except that it doesn't count! The boards are clean with no obviously burnt parts. The Nixie display shows only all zeroes. although sometimes when turning the range switch the least significant digit will show a 1 or a 2 which stays there. So does anyone have a scan of the schematic? Or a photocopy? thanks Charles ------------------------------ Date: Mon, 25 Jun 2007 07:49:11 -0400 (EDT) From: stuck in 50s Message-Id: <200706251149.l5PBnBJ3022061@fracas.netboobie.org> To: Old Tube Radios Subject: Re: Want to Save 500kc? Here's how! >So that means I can use my 318 foot insulated base tower >near Macon GA as a vertical? Next year there'll be a special field day mesage on 500kc. You watch Big bonus BTW, K6KPH louder on 14047 @ 0030z 6/24 than W1AW was on 40 @ 0000z. Perhaps loading "that tower." there. Msg was lotsa URL addresses & blog commentary on CW. >What is the power limit? How deep is the ocean? ------------------------------ Message-ID: <000001c7b72a$5c761360$7230bb40@k9a1e1> From: "John Gillespie" To: Old Tube Radios Cc: "old tube radios" Subject: Re: Looking for HP 5425L schematic Date: Mon, 25 Jun 2007 09:08:57 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi Charles: I have a 5245L as well, and it acts up every year in the early spring by refusing to count. In my case the on/off sample rate control pot is the achillies heel. I think it is affected by dampness in the air. It runs all winter perfectly while the heating system is on and quites as soon as the weather turns nice, its been doing it for ten years at least. If I turn it off and on rapidly a bunch of times it oftens restores the count. When desparation finally kicks in, I pull it off the shelf and clean the pot and its good for another season. Also I find the boards are prone to oxidation at the edgeboard connections. Every once in a while I pull the boards and clean the edge pcb connections. Both methods have restored mine to a fully functioning unit too many times to remember, hihi. Good luck......john Subject: Looking for HP 5425L schematic > I have acquired an inexpensive HP 5245L counter in nice condition - > except that it doesn't count! ------------------------------ End of BOATANCHORS Digest 4062 ******************************