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A quarter-Watt 10 ohm won't get hot until there is a breakdown. 73

This was a classic "swiss cheese" failure. Multiple boo-boos had to all line up with each other just right. Turns out a redundant system would have kicked in and prevented loss of rudder authority and propulsion if it had been configured properly. That one bad connection should have had a backup...

If it changes frequency when you turn the channel selector and gives you the right channel, it can't be bad. 73

Or if the crystals in the sideband filter have drifted or failed. Or both? 73

Works fine for receive. Don't know the math to predict the transmit wattage it might tolerate. Besides, an air variable used outdoors will have to be protected from rain and condensation. Got an enormous air variable I need to unload that has 5/8-inch spacing. Never did find a practical use for...

There are two other coils alongside that one, L21 and L22. They should affect sideband modes only. Rock the slug in each one, just enough to return it to the original position while watching the radio's frequency. If either of those causes a change while in AM mode, there is a switching fault in...

Pretty sure L20 is the adjustment to make AM line up with the sideband modes. 73

Shoot me your PayPal addy and I'll buy them that way if you like. Or send a money request to PP member nomadradio@yahoo.com. 73, Chris

Probably 47pf. We use 22pf, but clearly it's not all that critical. The big deal is to remove C163. 73

Roger that. The 5221 is a Read-Only-Memory that stores the binary codes that feed into the PLL section. And it's a dead duck without that negative bias voltage. Should survive that side of the power supply shutting down. Just won't work without it. Oh, and it's not an "E" PROM, just a ROM. No...

73

So far only the one that mounts inside the Browning Mark 3 SSB transmitter is listed on fleabay: https://www.ebay.com/itm/116884814172?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5336136228&customid=&toolid=10001&mkevt=1 The version that fits inside the Siltronix 80 or 90 VFO is set up a...

The plus two was famous for a somewhat "shrill" sound. Yours may be worse than normal, but the boosted treble and reduced bass tones were meant to improve "punch". And a shrill woman's voice in an echoey room could make your ears bleed if she used a plus two. 73

I understand the rules and wish to enter the contest. 73

It's one of the displays you can get with the Troy Radio DDS VFO setup. That one fits nicely behind the channel number window on the front of a Browning Mark 4A transmitter, among others. 73

R215 and R213 are in the 10-Volt regulator circuit. This suggests that Q35 and Q37 are damaged, and maybe D72 and D73 as well. Only way to fix that section is to take both transistors, the diode and zener each loose to test. It won't work until all those parts are functioning properly. 73

Found this listing on fleabay: https://www.ebay.com/itm/355777547157?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5336136228&customid=&toolid=10001&mkevt=1 The one in the listing's picture has the same IR logo as the pic above. 73

Well, okay. Maybe the title is a little over the top. Even so, parts suppliers I have relied on for years are falling by the wayside month by month, year by year. All Electronics was a reliable source of 'second-source' electronic parts. Prices were a fraction of the regular catalog sources...

The ERF9530 was not designed as a RF power amplifier. Its original purpose was to switch DC power-supply current, typically in a switchmode regulator circuit. But it was adapted to use as a RF power amplifier because that type part is produced in large quantities cheap. The MRF300 is a 300-Watt...

It's not quite as simple as "change a crystal" like some radios. The commercial "EXPO 100" channel-expansion kits for this type radio contained an oscillator circuit along with the quartz crystal. It would "force feed" a mixing frequency into the 29's PLL circuit and cause it to lock onto...