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Hello, I currently have a Dentron clipperton L that I have been tinkering with and I know that some of the last models had a tuned input that came with the amp. I¡¯m looking for a manual/schematic for this as I¡¯m wanting to build one to put in the amp. I have a CM-1 but just trying to eliminate some cabling. Here are some pictures of the cleanup/restoration.
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Need advice on HV connectors
38
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
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Amp Supply LK800 Meter/ALO Board Question
14
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
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12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 21
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
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Greetings to the Group, I bought a Peter Dahl transformer for use in a 1296 MHz tube amp using 2C39/7289's. The P/N on the transformer is ALS4T and the serial number is 06/14/01. Albeit a custom transformer (as I believe most were), I recall this being in his catalog. However, the ones that I can find (mid 2000's from Harbaugh) do not have it. Might someone in the group have something earlier than this that might have it in the price description pages? Modest in size, it is a hypersil design with a 110/220v primary, 6.3v filament, and a HV with C.T. I'm trying to figure out the HV secondary ratings. Peter Dahl P/N ALS4T. Thanks in advance. 73, Mike K9MK
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File /Peter Dahl catalog.pdf uploaded
#file-notice
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
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I understand a chap in the UK has made the seller aware of the utter poor quality of this linear I wanted to know who built it with two plate chokes in series? At least they knew to place them at right angles.... but why so much L? https://www.ebay.co.uk/itm/356199751140 hurry and see it before someone buys it ? as my Scottish friend would say "Perish the thought!" Reid W6MTF
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Equipment Interconnect cables
17
Hello, In HF service, when running interconnect coax cables from an amplifier outbound, I have always used RG-213 or equivalent from the amp to whatever accessories I was using at the time such as a monitor scope, power meter, ATU, etc. then on to the antenna. Since the interconnect cabling are usually very short lengths, is it acceptable today to use RG-8X for this when running high power or is it standard practice to use the heavier coax? 73, Garry
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Amp builders might be interested in this like 20 dollar gadget. Its marketed as a IGBT tester however it can test any component to 3700 volts upto 5ma. https://www.ebay.com/itm/296767679099?_skw=igbt+tester&itmmeta=01JCF3RQH1VS60KP7SWVR49KF5&hash=item4518bb6a7b%3Ag%3AmPEAAOSwofVnF3Fx&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKkTu8qSspIOpj1Pr%2FkVy2zBH0DDKWrHoBF6DV%2FvDTdUo%2FroUqWTtQDQ1pPLUiVetndgzphdCZp2U2sBLo6monVSnaeG%2BhS0VVQsORMQSsjhfHJRr2lJURzuo33foGqSYJKg7ViuCIwDbgFnYuIJhUoxVhSWEofoPou8ZftmUpkZf4ZSsl90ttfizhkizjAUzOmt526RaEpGfe4u%2FUge6bd21v3EaNxjcY8MBgQUSRx7NN29svRs7p2aNplSB81ckkJrn3BkkvTV9Tj4LyN3ZPkf%7Ctkp%3ABFBMzvji4-Nk&var=594575090972 I have used it to test MOV's Gas tubes, Zeners, leds, capacitors, rectifier diodes, coax connectors etc etc Its really handy when you dont want to pull out the big hypot It operates in two test modes. You connect the device and just push the button and it will indicate the voltage that the DUT flashes over. The other mode is that you can disconnect the DUT and dial in the expected working voltage then it will test at the dialled voltage. I generally start on low voltage and increment up till I hit the flash voltage. The voltage output is very accurate. You can find them on all the Chinese auction sites Its been a fun toy. Maybe one of these days they will make a 10 or 15KV version which would be handy. You can hear from the whine that its using one of those HV switchmode booster modules. It sources 5MA so you can test strings of series zeners when wired in reverse. Very handy.
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I'd like to know if any of you have suggestions as to what caused this HV arc to chassis and hopefully, what to do to prevent it in the future. Amp is a TenTec Centurion. It was at idle when the arc happened; no RF applied. The glitch resistor took the brunt of the discharge, thank goodness. I've replaced it, even though the original still measured the correct resistance, it was visually damaged. The event spooked me...new pair of 3-500Z tubes was in the amp; no apparent damage. The insulator appears to be made of fiberglass. The glitch resistor is on the opposite side of this aluminum panel. The HV feeds through from the resistor via the machine screw. Any thoughts? Thanks, Robin Midgett K4IDC
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During my move from the city to an extreme rural area, I had a Henry 2K-4, along with a spare set of 3-500Zs, gifted to me. I'm presuming the 2K-3 is a more modern looking 2K-3 and I have a '7300, so the thread combining the 2K-3 relay update and the 7300 "tail" is interesting. I am the 3rd keeper of the 2K-4 and was told it was bought after demonstrating its functionality, but "something happened on the way home". I've looked it over closely and the only things I've found were a wolf spider that jumped onto my hand (I said a couple of bad words), a NEMA 5-15P (regular 125VAC plug) on the end of the power cord, the amplifier internally strapped for 240VAC and what seems like a decade of dust covering everything. The dust is now gone, as is the wolf spider. So my hope is that someone had a Halloween special regular outlet hooked up for 240VAC, but everyone else has just been plugging it into a correctly wired 125VAC outlet.. I have not powered up the 2K-4 due to a lack of a 240VAC circuit in the shack. I have the stuff to add a 60A/240VAC sub-panel in the shack, but...other projects are taking priority. Eric WB6TIX
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Plate & Load
6
Been an AMP user for almost 50 years. But have a question. The Plate/load/coil match the tube(s) output impedance to the desired antenna impedance typically 50 ohms. Just like a tuner changes a non 50 ohm antenna to 50 ohms. But I just thought of this. in the antenna tuner the two caps can be and usually are all over the place. And their tuning is typically rather broad. the caps are not super tight. But in an AMP The Plate control is very critical and narrow in optimum setting. And It's level of "C" is almost predictable. You KNOW the 40 meter will have less "C" than 80 meters. And so on through the bands. The load cap is almost in the same position and in almost every amp I have had the optimum was rather broad. Why? Joe WB9SBD
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Econco 3cx3000 Rebuild cost
5
Anyone had any experience in getting a 3cx3000A7 rebuilt with a supplied Eimac Dud? I would be curious if its worth the cost and what the cost is compared to buying a new Penta 3cx3000. I have a few 3cx3000A7 duds from Henry RF heaters as well as 3cx3000F1 ones which I am told Econco can rebuild as a 3000A7. Henry
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Electrical Improvements
10
The revised electical laws regarding grounding of appliances and not using their chassis¡¯ as a.c. returns hit home one day when I was cooking . I was stirring something on the electric stove with a stainless stirring spoon and reached for the ¡®fridge door so I could retrieve an ingredient, and there was some sort of fault and I got knocked on my ass. The fault voltage, later measured was 65 volts from the chassis of the electric stove to the chassis of the refrigerator. I showed this all to my LL¡¯s son and he took a chance on touching the pair of appliances at the same time, too. Sears was there the very next day with a new ¡®fridge and a new stove. Bless someone¡¯s heart¡. Hal Mandel W4HBM
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TL-922A transmits when switched from standby to operate.
19
My TL-922A, which has been working flawlessly for quite some time, is now going into transmit mode as soon as the switch is changed from standby to operate. What has changed is I rearranged the shack, so had all equipment disconnected for two days. The amp stood on end over in the corner of the room for that period of time. Reconnected everything yesterday, and used the TS-890S barefoot for a contact with C21MM (Nauru). The amp was connected but not powered on. When I went to use the amp this morning, this behavior showed up. I have disconnected the RELAY and ALC connections. No change. Powered off and on several times, No change, Disconnected the RF INPUT cable from the TS-890S. No change. Any ideas about what might be causing this and how to fix it? -- Jim McPhee Placitas, NM W5ABA
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RM Italy bla-350 plus reviews
Thinking about buying a bla-350 to use with my ten-tec Omni VI plus. Has anyone used a 350? Is it a decent amp? 73's Mike
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Ok the fellow who gave me the SB-200 to repair now has it in his possession again with no smoke! However, he said that the antenna relay is hanging up just like the problem he has on his AL-80. I know for a fact that it has the Harbach ¡®soft-key¡¯ keying interface installed. The common denominator is his FTDX-10. I am not familiar with that rig at all. I understand it is possible to use 2 ports on the back as a key line. Having said that, is there a software setting that sets the key line or would keep it high? He says he has to shut ¡®everything¡¯ down before it returns to normal. I won¡¯t be able to visit his QTH and examine it myself until sometime in Oct. Is there something else I should also check out when I do go? He is a smart ¡®cookie¡¯ but sometimes he can¡¯t see ¡°the trees for the forest!¡± Thanks in advance. Mod-U-Lator, Mike(y)/W3SLK
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12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 20
12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 20 Misc info on how this project goes together. Bottom of RF deck cabinet will hold the blower, fil xfmr, chain drives etc, etc. The HV supply will reside in a separate cabinet, with the pair of 150 lb magnespec plate xfmrs, FWB assy, contactors, 20 x 2500uf lytics etc. https://www.youtube.com/watch?v=-BOYflhiVcE
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RMItaly BLA600
10
Fixing one of these up, had a blown LDMOS FET now ok on CW, but SSB trips a lot of error protect faults related to I think the peak power during modulation input to the amp. It claims > 25W is what brings it into protect and my Kenwood 930S trips it in SSB no matter how low the output is. My KW 850S has better Carrier and FR out controls, so I can bring it down much lower and it seems to be ok with that rigg. This is running on 110V hookup, I get about 450W CW carrier, and most I can see on the average analog power meter is like 200W and thats almost full bars on the amps power bar meter on the front panel, so I am left to believe this is its intended operation without using ALC? The owner of the amp uses an ICOM 706MK2 with no ALC on the AMP, but I believe it does have an ALC output. I have never ran an amp with the ALC from the rigg, but its suppose to I guess limit the spikes I am seeing which also reduces the buckshot side splatter from the inherent IMD they produce? -- Steve Hearns [ KA2PTE ] Technotronic Dimensions, VT [USA] WWW.TECHNOTRONIC-DIMENSIONS.COM E-Mail: Steve@...
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12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 19
12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 19 The RF deck is finally completed !! Bias diodes installed.....and also the hb ferrite loaded plate choke. (393 uh, and series resonates at 17.650 hz....and also 30.1 mhz). A pair of .01uf @ 30 kv disc caps installed at cold end of plate choke...along with a 750 pf @ 15 kv doorknob cap assy. (2 x 1500 pf @ 7.5 kv doorknobs in series). This is a thing of beauty, but was one helluva lot of work + effort. 160-80-40-20-15m....that's it. Output side has all been mapped out. No padding used on either vac tune or load caps. On the input side, air caps are padded on 160m only. Vac relay's used for the input + bias, and also 2 x more in parallel for the 12 kw output. Everything is rated for 100% duty cycle, brick on key CXR. Next up is the hb 7500 vdc B+ supply....which gets installed at bottom of the same rack...along with the fil xfmr and Ebm-Papst 330 cfm blower etc. 20 x 2500uf @ 450 vdc lytics will be used in series. (125 uf @ 9 kv)...along with a pair of 7.5 kva CCS identical plate xfmrs, etc. On a side note, I made up several of those ferrite loaded chokes. On my own choke, I made it a bit longer, and it series resonates @ 16.2 mhz.....and also 27.99 mhz. The 16.2 mhz is midpoint between 20+17m. On Scott's amp, due to height restraints, I had to make the choke shorter..... and his 1st series resonance @ 17.650 mhz is midpoint between 20m + 15m. Once the B+ and fil supply are built + installed, final testing and calibration can be done. https://www.youtube.com/watch?v=9ZUrb3vqfSc
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Sat 8:39am
Sat 8:39am