Search results

A surface mount power transistor? The foil surrounding the part becomes the heat sink. I have no idea how to calculate the foil area required to carry the heat away from that kind of part. 73

A comprehensive cross reference between Uniden circuit-boards numbers and the brands/models where they were used would be really cool! The XLR radios are different from all later 40-channel Cobra models. President's name became Uniden some time in the 80s. But only in the USA. I have a vague...

That diode was famously vulnerable to getting toasted by touching ground on a loosened mike socket in mobile radios with that circuit board. Even briefly touching grounded metal would pop it. We adopted the habit of lap-soldering three 1N4148 diodes in series, to replace D71. For some reason...

I would unplug the bias-test jumper, sometimes called the "mirror board" and see if the radio will receive normally. If so, shorted driver/final transistors are causing the mischief. 73

Chicken or egg. Electroluminescent (EL) panel or bad inverter. If you have a 'scope check for at least 100 Volts peak-to-peak feeding into the EL panel's flat conductor. If you have drive voltage, the EL panel has gone bad. No idea how you'll turn up one of those. If the inverter is dead, and...

Is it "catching" mechanically? Or is the power to the motor failing in one direction only? A funky limit switch sounds plausible. Found the owner's manual at BAMA. https://bama.edebris.com/manuals/wilson/wr500/ 73

Here is the other half of the lower-channel mod for the Browning Golden Eagle Mark 4A. The receiver this time. The receiver comes with two tuneable bands and one "fixed" crystal receive frequency. The crystal socket is part of the front-end circuit board. Adding a third tuneable band requires...

Cool! No ferrites on the output side. Gotta learn how to do that! But nothing about where he gets his 50 Volts. 73

We adopted the habit of unhooking the ground side of the input cable and inserting a .001uf disc cap from the wire to the pcb ground foil. This removed ground-loop buzz noises. 73

Tuning rings didn't help? 73

Holy moly! That should work. A diode with the anode on pin 3 of the display. The cathode would go to pin 3 of the mike jack. This would select the second offset value in transmit, and the first one for receive. Cool! 73

Consider that microphones break more frequently than radios, all other things being equal. 73

Probably not the transformer. First guess would be a resistor, but this model doesn't have that many. A close look at the resistor inside each parasitic choke, or the two 1-Watt resistors at the base of the plate choke, maybe? 73

Pretty sure the local-oscillator signal is still present at that test point for receive and transmit. The ALI Express OLED counter says it has two offsets. Might be able to jigger it to read properly for transmit and receive. The ad listing didn't explain how to select one offset or the other. 73

So long as you don't crack the meter movement open, that's not a big risk. 73

There is, but you'll have to choose whether you want to display the receive or the transmit frequency. The radio's PLL jumps down 455 kHz when you key the mike. The fleabay PLJ6-LED counter board has an offset feature you can set for most any radio, but the AM radios you mention all share this "...

This guy persuaded me 47 or so years ago that I'm not cut out for the SHTF apocolypse. YMMV 73

Only if you build a power supply for it. The power supply and AC cord reside in this model's receiver. 73

Good to hear he got posession of the stock. Greg told me how many tons, but all I remember is several. Gonna be a job getting it organized and cataloged for sale. Better him than me. With any luck I won't run out of any Browning-specific stuff in the meantime. 73

A radio that's too small for an amplifier that's too big will ALWAYS sound sweeter (and swing better) than a radio that's too big with an amplifier that's too small. This has always been the perennial favorite comination that we're used to seeing. The answer is always to turn something down...