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Have a factory made 8k ultra with spare plate transformer on the way. If not to screwed up I will fix and re sell. If beyond repair I will strip and part out. Stay tuned to my YouTube channel under amp repair guy for updates. I have been swamped with harbach orders and amp repairs. Hope to be back on the 160-15 meter pa soon.

Protection board install. Plate and also grid overcurrent protection. Both grid and plate meters have also been re-scaled to the new values required. https://www.youtube.com/watch?v=zfyRut3DgjI

I have an older AL-82 that works fine except the input SWR is right around 2:1 on 20m and it's just high enough to cause the K3 that I am driving it with to start to foldback so that the output power is 1200w max. Not that another couple hundred watts will really make a difference, but I thought I would try and adjust the input match coil slug on 20m. This older unit has what kind of looks like a cap on the coils. It has a flat blade screwdriver slot and also a larger hole in the center that looks like a hex tool would fit into. However, when trying even a larger hex tool through it, no less the plastic tuning tool I bought from DX Eng, of course with the unit off and discharged, it appears there isn't a tuning slug inside? Is the outside cap meant to rotate? I also have a much newer AL-82, and it doesn't have these "covers" on the coils and I can clearly see a tuning slug inside each coil. It looks like a job to get to this box to see the inside. Has anyone experienced adjusting the tuned inputs on an older AL-82? TU; Steve NY3A _._,_._,_

WD7S, on one of his boards he sold, was made to shut things down in the event of loss of B+. If I remember correctly, it resembled a mess of series resistors, like you would use to meter HV, (without the meter), and an extra smaller value resistor, in series at the cold end. The V drop across the small value resistor was like 5-7 vdc.... and was applied to the rest of the circuit. When the B+ dropped below a given threshold, the circuit tripped, and kicked the amp offline...like opening off the keyline etc. I think it used a spt, or dpdy mech relay..that was always operated, with B+ turned on. I think the coil was opened off when the circuit tripped. I can't find the original schematic for this board anywhere. Does anybody have any info on it ? Jim VE7RF

It appears I have a shorted 3-500Z tube in my AL-82 amplifier. It also appears that right now the 3-500Z or ZG tubes are unobtainium. Sellers on eBay are selling new Penta tubes for a ridiculous amount of money. Are Penta tubes any good? Perhaps I should ask first, who has 3-500’s for sale? I am going to replace the T/R relay in the amp while I have it open….Been a weak component in the amplifier since it was new. Been replaced twice now and the amp is only 4 years old. A friend who is an amplifier guru is going to look into building an external, plug in, relay setup for me. Then I could go to a vacuum relay and my T/R relay issues would be over! Just to be on the safe side, I just purchased 3 relays from Ameritron (MFJ) to have when they are no longer doing business. If I do the relay modification, the Ameritron relays should sell fairly quickly as it appears all their high power amps use the same relay. Thanks in advance, for any questions answered! Joe – W7RKN

I have a AL80B with a factory installed QSK-5 board. (new 2019) The amp xmit fine. Receive is down. Typically it's those stupid fuse lamps Lp1, Lp2.... Open cover, remove Lp1/Lp2 -- install new ones. Turn on AMP no problem, receiving fine. Turn STBY /XMT OPR on.. poof, lamps blow out. Try with nothing connected to amp, no control lines, nothing. Replace L1/L2, turn on amp, fine. Flip up XMT OPR , lamps blow out. Amp now has low receive, and plenty of output, receive is down -20 -30db . . All bands. Anyone seen anything like this?l've replaced these lamps 1x in 5 years, and it was a no brainer. Something in the receive chain? Pin diodes? ARGH.. Glenn

Here the plate block cap assy is installed. 5 x 200pf @ 15 kv rated doorknob caps are used to make up the assy. The 200 pf cap's were chosen since they are rated at 15 amps CCS of RF current on any freq > 5.11 mhz. Total max current rating is now 75 amps. Total capacitance is 1000 pf. (The 200 pf HT-57 cap is the....'go to'.... cap for the HT-57 series since their 200 pf cap has the highest current rating of the entire HT-57 series). Similarly for the bigger HT-59 series, the ...'go to cap'.....in a HT-59 is their 250 pf cap, rated at 35.5 amps CCS on any freq > 16.0 mhz). 1000 pf = 88 ohms of XC @ 1.8 mhz The general rule for plate block cap total value is.... The XC of the plate block cap assy shouldn't be any more than 5% of the plate load Z...at the lowest freq used (1.8 mhz in this case). In this case, with 7 kv loaded B+ @ 2.5 amps, the plate load Z = 1555 ohms. 5% of 1555 ohms = 78 ohms. 1200 pf would have been 73 ohms of XC.... but in this case, there is severe space restraints, and only 5 x caps can be used. Close enough for this application. 2 x copper straps used, one above, and one below..... with the input at the tube end on top.... and the output at the opposite end...on the bottom. Done this way so the total physical, combined distance in + out, stays the same for each cap. Done this way, the RF current is equally divided between the 5 x caps. (Another similar method used, when 6 or 8 caps are used, is 2 rows of 3 caps.... or 2 rows of 4 x caps. In those cases, the input is dead center between 2 x caps at left side of the top plate...and output is dead center between last 2 x caps, at right side of bottom plate. Same deal, the current will divide equally between the caps). HEC (high energy Corp) sez the PEAK RF voltage ACROSS the cap (or paralleled cap assy).....PLUS any ...'DC bias' can not exceed the stamped cap's voltage rating. What HEC calls ...'DC bias', we call B+. The saving grace at the low freq end (160m) is.... there is hardly any RF current flowing through the plate block cap asy.....and the peak RF voltage is very little. At the upper end of the HF spectrum, 10m, there is a LOT of RF current flowing through the block cap assy. Reason is..... the anode to grid C on the tube makes up 90% of the total required C1 tune C. Think of it as the tube C is 90% of the required C....and the actual C1 tune cap is a tiny, variable padder. Issue is.... the plate block cap resides between the anode and the C1 tune cap. All that current that flows through the tube C now also has to pass through the block cap assy. The XC of a 1000 pf cap on 29 mhz = 5.5 ohms. So even with high current flowing through the block cap, the peak RF voltage is still miniscule. Just to recap, enough C is required for the lowest freq....and the cap has to be able to handle a lot of current on upper HF. https://www.youtube.com/watch?v=bMmCXeB_cew

12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 17 Here the grid and plate overcurrent protection, plus grid current and plate current metering are being done, using existing boards, with some component values modified for this application. The idea here is to be able to re-use the existing metering (100 ua meter movements), and re-scale them to what's required in the new amplifier. Existing metering (and mating overcurrent boards) was for another amplifier, which used lower value scales. Scott has several of these boards, all functional, so it was decided to re-use em for this application. https://www.youtube.com/watch?v=0LaIcnQBuTo

I have an Ameritron 811H and a Dentron Clipperton L amplifier that I was driving with a Yaesu FTdx3000 through the Ameritron ARB-704 interface (only one in the circuit at a time) . I am using the plug and play cable between the 3000 and either amp. Now neither amp seems to key. With the amp in standby all seems well and I am able to communicate as normal. It would appear that the relay on either amp does not closes. I.E., when I PTT on the transmitter I get the 3000 transmit LED as well as the LED on the 704 but nothing on either amp. I was planning to try to read out the voltages coming out of the linear out connection on the 3000 for a starter. Being both amps are acting the same I am thinking that the problem is with the 3000. Lastly, I will not totally rule out operator error. Any and all advice On what I should check or how I should proceed is appreciated. Attached is a pictorial of my set up. Post note: don’t know if this is relevant but rereading the 704 manual it states that 13.8 volts is coming from the transceiver through the plug and play cable. As a result no external power to the ARB-704 is necessary. In addition to the plug and play cable I have had a 12V wall wart feeding the ARB-704. Fortunately, I didn’t see any ill effects before this point. Thank you. 73 Harrison N1FAM

It's still in a transitional phase as of today. A lot of items are being shipped from OH to CT. A lot of new items will be added, including the entire Penta tube lineup, for both amateur and commercial users. https://www.youtube.com/watch?v=eGAnM8Tboms

Hi, FYI new email below: Philw9ixx@... 73, Phil W9IXX

12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 16 Here all the various tank coil taps are completed. Adjustable SS spark gap installed across the vac load cap. After this video was done, the 2nd adjustable SS spark gap was installed across the vac tune cap. Spark gap across the load cap protects the load cap. Spark gap across the vac tune cap protects the vac tune cap AND the bandswitch. There is also a.... '.7 uh pre-coil'...... that is wired between output of plate block cap assy....and the hot side of the C1 vac tune cap. The anode to grid C + stray C (lower anode fins to chassis) and this .7 uh pre-coil form the step down L network. This transforms the 1600 ohm plate load Z (7200 vdc loaded @ 2.5 amps) down to just 361 ohms @ 21.225 mhz. Then a lower, loaded tank Q can be used for the PI network on 15m. That L network also has a lesser effect on all lower bands. IE: 939 ohms @ 14.175 mhz. 1419 ohms @ 7.150 mhz etc, etc. The original target value for the pre-coil was .6 uh. (which would have transformed the plate load Z down to just 483 ohms @ 21.225 mhz). Trying to tap a tubing coil is tough enough as it gets. With the temp 1600 ohm resistor from anode to chassis....and analyzer on output side (and the pair of RJ2B's relays externally powered on), the swr was 1:1 after tweaking the tune + load to the calculated values for each band = jives with the spreadsheet / GM3SEK software. Previously, both the vac tune + load caps were mapped out, with pf vs turns counters....and a cheat sheet made up. On a similar note, once the tune + load caps tweaked for 1:1 swr, the caps are left alone....and the upper / lower freqs for the 2:1 swr points are noted down. 160 khz wide on 160m, 310 khz on 80m, 600 khz on 40m, 800 khz on 20m, and 1 mhz on 15m. So far, so good. All measurements for the adjustment of the tune + load caps were done with the top lid on. All playlists. https://www.youtube.com/@amprepairguy/playlists

Hi all, Tomorrow I'm going to see a friend that has some kind of problem with his LK-450 NT amp. At this time I have no idea what the problem is due to inconsistent information. But I have a question, I've never worked on one of these but I'm assuming the network is very broad banded and you only adjust a "fine tune" for your operating frequency. My common sense tells me that inside there must be some kind of "broader" (lack of a better term) adjustment inside to get the network in the ballpark so a fine tune can dial it in. I'm thinking that especially on 160 and 80/75 it would be critical to get it close for either the top of the bands or the bottom of the bands. Am I on the right track? Also, is there any known common problems I should be aware of? Thanks all. Bob W4JFA

Any of these bigger metal tube amplifiers can be used for: (A) ISM (B) educational (C) testing DL's. (D) CAP (E) MARS (F) plasma (G) sputtering (H) tube testing (I) deep tissue healing (J) diathermy (k) low latency, high speed stock market transactions (L) SW broadcast (M) marine Superbowl 6 (O) Embassy (P) CQ WW (Q) Etching (R) emergency use (S) military (T) irradiation. Ok, here's the deal. Next time some bozo asks.....'where is this amp legal'....and 'why so much power' they can look at the above list....and pick one or more at random.

HERE THE FRONT PANEL IS DONE..AND PAINTED. THE 2 LOWER TURNS COUNTERS EACH DRIVE A 6:1 VERNIER...WHICH DRIVE THE C1+C2 PI TUNED INPUT CAPS. THAT MEANS 0-300 INCREMENTS TO GET FROM MESHED TO UNMESHED. https://www.youtube.com/watch?app=desktop&v=9ZCBgp1-Kaw

Does anyone know where a replacement relay can be obtained? Or the manufacturer's name and part number? Thank you.