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Years ago Gary made a relay-driven protector when it was seen that a large RF signal could damage the circuitry of the transceiver¡¯s RX2 port. It turned out to be an excellent RF amplifier keying driver as the high quality of the driver relay provided a worthwhile isolation. There are a number of available products these days, I hear. Like I.C.E. Products, the KD9SV stamp is to investigate. Hal W4HBM

Happy New Year, I have a fully assembled, tested, but never used Heathkit Shop power supply upgrade board for Drake amps for sale. Price is $125.00 plus shipping from 23418. Details and pictures are available on request. 73, Garry - K4OR k4or@...

I'd like to acquire a 10 - 50 watt linear power amp to use with a 50 MHz. beacon transmitter. Input must be in the 10-18dBm range. Kit or assembled or "needs repair" is fine. Suggestions? Thanks, Robin K4IDC

I have a transformer company that might be able to assist. Does anyone know the exact spec of the Ameritron AL-80B power transformer? I'm assuming secondaries are 9VAC @ 1.5A, 3.53VAC @ 15A, and 1100VAC @ .6A I have dug through the manuals and can't find anything specific. You can see the voltage doubler in the schematic though. And if 3100 No load volts is the DC target for B+? Thanks! Warren (WR0S)

Hi All, I've appreciated all the info that I've gotten on the Kenwood TL-922A and I've ordered the relay switching board from Harbach. While I'm in there, I'd like to address the filament voltage. I've looked for info on how I might do that, but I'm not finding what I want. Is there an easy way to do this that has been done and I can get the docs on?? Any info would be appreciated. BTW, I've had my electrical service here upgraded and my line voltage here measures around 250 VAC. So that filament voltage SHOULD be addressed. Thanks!! -- Kim Herron W8ZV w8zv@...

Mike, Try this: https://web.archive.org/web/20180408212726/http://www.ifwtech.co.uk/g3sek/boards/tetrode/tetrode-1.htm 73 Bill N4LG At 11:17 AM 12/28/2024, Mike Peace via groups.io wrote: >Hi,? >Would anyone have the G3SEK schematic and PCB drawings for download? > >The link seems to be broken for me: ><http://www.ifwtech.co.uk/g3sek/boards/tetrode/tetrode-1.htm>http://www.ifwtech.co.uk/g3sek/boards/tetrode/tetrode-1.htm > >Cheers, >Mike Peace >VK6ADA > > >On Sat, Dec 28, 2024 at 9:52?€?AM Mike WB2FKO >via <http://groups.io>groups.io ><mph=<mailto:[email protected]>[email protected]> >wrote: >The tetrode boards aren?€?t particularly >complicated if you only implement the screen >current trip. On my tetrode amplifier, I >eliminated the control grid current trip and ALC >circuitry. Their primary purpose is providing >regulated screen voltage with most of the larger >components placed off the boards. The schematic >diagrams are still available on G3SEK?€?s >website so spinning up an equivalent set of PCBs >¡ª perhaps just one PCB is all that?€?s needed >??€¡± should not be difficult. > >Mike WB2FKO > >>On Dec 27, 2024, at 9:03?€?PM, Billy Pickering >>via <http://groups.io>groups.io >><pickeringw=<mailto:[email protected]>[email protected]> wrote: >> >>??? >>Well, I was lucky enough to pick up a Henry >>Tempo 2006 that did not have any tubes. Yes, >>3CX400A7 tubes are expensive so we were looking >>into modifying it to run 2 or 3 4CX250B tubes >>instead. I know we need to have screen power >>for these tubes, and was wondering if anyone >>was currently making the GM3SEK tetrode control >>boards. I guess we could come up with something >>from scratch, but those boards are really nice. >>? >>I guess if it really come down to it, we could >>modify to run the single 3CX800A7 we have, but >>not sure if the tube is any good as it was >>pulled from a commercial unit. > >

Sorry to be a pest guys!! I've become the proud owner of a Dentron DTR-2000L amp with a broken tube socket and a missing cooling fan. This came from an estate and I'm sure that the SK was not using this amp. I could use a suggestion on a fan, as I understand that the muffin fan was NOT a good choice for a fan. The other question is if any one here has had experience with the Chinese sockets on E-Bay. Here's the auction number. 184967626094. $38.50 a great price, if the thing is any good. Any thoughts would be appreciated! Thanks!!! -- Kim Herron W8ZV w8zv@...

FYI: "WARNING: Never mix ammonia with bleach. This causes the release of toxic chlorine gas, which can be deadly." Read ingredients of the products you are mixing. If they have the above in any amount don't mix. Dale, K9VUJ

A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would like all the PA0FRI mods done to it. See http://www.pa0fri.com/ This is no big problem, as most of the mods are common sense and they are what one would normally do to an amp. However, there is one mod that strikes me as odd. He suggests cutting the grounding wires on VC1, the plate tune capacitor, and running a thick wire or coax from the cold side of VC1 to a ground point at the base of one of the 572B sockets. This seems very odd to me. I don't see how this would enhance stability, having that grounding wire running all that way. Every amp I have seen or built, has the cold end of the capacitor bonded to the nearest point on the chassis. Should one be doing this mod? My feeling is that it should be left alone. Opinions appreciated. Thanks, Alek. VK6APK -- From sunny Binningup Family Businesses: SP Electrical. www.spelectrical.net.au The Velvet Fox. https://www.facebook.com/TheVelvetFox/ Smart Design Electrical. https://www.facebook.com/smartdesignelectrical/ Perth Interiors. https://www.instagram.com/perthinteriors/

HI all, Thanks for reading the mail. I have acquired a home brew amp and power supply that is missing its HV cable. I'd like to change both of them to one style since they are both different. Jack Schutt K9GT originally built this. I'd thought about using SO-239/PL-259's that are Teflon with RG-8 inner conductor cable as the HV wire and packing the PL-259's with RTV-108 and sleeving the wire with GOOD Belden heavy shrink tube with sealant. Does that sound like it would hold 5 KV since that's what Jack built the power supply too? Thanks for the input and reading the mail. Kim Herron W8ZV w8zv@... www.goldenradioservice.com 616-677-3706

All- I have an Amp Supply Company LK800A amplifier that puts out full power. However, I noticed recently that it shows no grid current reading when transmitting on multiple bands. This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience. I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading. I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms. No other parts look visibly damaged. The LK-800 series manual does not have a schematic for this board. I was able to find one at http://www.radiomanual.info/schemi/ACC_PA/Amp_Supply_LK-400_LK-500_series_user_1988.pdf. While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board. The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29). I suspect this is the problem. The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board). My question - can someone verify that R29 should indeed be 18 ohms? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain. Also, do you have any insights as to what would blow this resistor? A current of 120 mA through that resistor would deliver 0.25 watts... I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue. Many thanks, -Mark

12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 21 125 uf @ 9kv dc Capacitor Bank for the 7.5 kv B+ supply for the 160-15m 3CX-6000A7 PA. Each cap is 9.8 Amp CCS Ripple Current rated @ 120 hz. .041 ohm per cap ESR...also @ 120 hz. Here the 20 x 2500uf @ 450 vdc caps are mounted....and will be wired in series. These are 95C rated units, made by CDE. Each cap will get a 100K @ 3 watt MOF across it. The entire assy will drop into the base of the cabinet. https://www.youtube.com/watch?v=kMY8q7vJ3Yg

The following items have been added to the Files area of the [email protected] group. /Peter Dahl catalog.pdf By: Jim VE7RF <jim.thom@...> Description: Peter Dahl catalog