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I'm a newbie to Lifepo4 & got a 100ah. I've read mention about using a regulated power supply with current limiting to charge but there never any details. Maybe I'm over-thinking it. If possible, I'd like to user my Astron VLS-35 for charging. is it really as simple as setting the voltage...

A while ago, I lost plate current and found it was the single 5408 diode from B- to ground ("D-2", bypassed w/ low voltage .01 ceramic). The diode went open/No Connection. I replaced the single 5408 with two in series (same batch) bypassed w/ 2x .005 Z5U ceramics). I got zsac back but...

Experimenting w/ shorting unused section of roller inductor before I replace it with some other device. 1st try yesterday: 5.6uH molded choke (1w sized-body) series connected to a 250w 50 ohm RF termination resistor w/ heatsink (TO-220 size). Seemed ok on 10 & 11 and 20 into DL with 5w AM...

I was looking up Yaesu’s FT-767GX (MRF422 finals) and CoPilot’s Answer/Reply credits WorldwideDX. Nice work gents!

I’m nearing the end of my 4cx rebuild -for this year anyway- and the resistor I’ve had between HVPS and plate choke has seen better days. It’s a single long body ww from almost 2 decades ago. After checking the W8JI website I see there is a better part for this function: RCD Part Number...

American UA748 op amps are getting hard to find. Have a batch of UA748's from PRC but I do not want to use them because they show different test results. Anyone ever use a metal can type IC in pcb mounted DIP-8 socket?

I have the datasheet but I'm not seeing anything that specific. It's an Opto22 series, DC60P, 3-24v control signal max. Preparing a mock-up w/ 2 DC supplies so I can get a feel for it on the bench before I try to use it. I get that it's a current device.

Looks well designed but I do not recognize the big copper colored part attached between the roller and ground. What sparked my curiosity is the Roller itself. My project makes far less than the 8877 but my roller gets very unruly at times. Roller looks the same but arcs to ground at various...

I scrapped the messy rotary switch inside blower box in favor of a relay switched, parallel inductance to RF ground for driving the grid-driven tetrodes. I re-purposed a four (4) band LPF board to reduce lead length and add a nice ground plane for the connections & components. The LPF board is...

I found this app helpful in drafting a diagram for a tuned input and best of all it's free w/ a DigiKey account. It has Symbols for cut & paste. Wish I knew about this a few years ago.

Since my big bang event a few months ago (homebrew 4cx300a amp), I’m planning on taking advantage of the required disassembly / troubleshooting to replace the RF input (parallel inductance a’la Pride) rotary switch circuit with a 4 band relay board fashioned from an LPF kit. It should fit...

While I was doing my audio thing these past few months, I found a good YT repair site: Mend-it-Mark, from the UK. The vids allow viewers to watch his repair of assorted devices. He recently received a Copyright Strike for his repair video of a phono preamp that sells for £25k. What's more is...

Goes way back

Lightly used EMS-14 desk mic. This is an Alinco mic not the look-alike clone. Purchased new in or about 2010 (I probably have original packaging and probably the Receipt too) been in the original box since for but 2 years use max. I do recall that the removable foam element cover (windscreen)...

The lowest Tune capacitance I can apply with an Air Variable is about 15pF. That minimum Tune C reduces PO by nearly 80%. Yet, with no Tune C connected at all (L network Tank) I see about 1:100 PO w/ reduced plate volts/mA. The RF Input parallel resonance revisions appear to work fine...

My FT891 only goes down to 5 watts and shuts off if I lower the VDC below 12v. A series resistor sounds like trouble. How far can I reduce the 750 ohms 'swamping' resistance to ground without altering the input impedance a'la Pride formula? It would make tuning & trouble-shooting easier if I...

11M test just now showed over 400w AM from a 1970's 23 ch CB barely powered by a 12v, 2 amp bench supply. Amp still on work table so I was only using one plate transformer (1800 400mA). That's a best ever for 27Mhz especially given I did not even tweak Tune, Load or RF Input, just took a good...

Regarding the plate choke (thanks again Nomad) I compared with my old choke and found that it was roughly twice the inductance of W8JI's component so I'm hopeful that I'll see improvement. Over the past 2 months I replaced the point to point wiring of the RF Input I had strewn about the tube...

Found these handy screw terminals on ebay. They fit snugly and the metal is strong. Seller wants $3-4 for 7 of them. The screws are fine thread. https://www.ebay.com/itm/181677244055?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5336136228&customid=&toolid=10001&mkevt=1

Pictures and a hearty discussion of circuit