Search results

Got told I should buy a cri-cut tool to make aluminum discs for Siltronix knobs. Never found out the upper limit on thickness to cut aluminum with it. Makes me wonder if a leather punch would do this? 73

Tonight's evening shift was short, but it's progress. Got regulator and caps on all 9 prototype boards. Told some folks about using it in a Browning receiver. So far some of them are sold before they're built. At least it's an incentive. The Uniden SSB carrier crystal trick will have to...

Yeah, that's the starting point to look for flat-topped modulation peaks. 73

I'm used to depending on an oscilloscope for this fault. Main thing I want to know is whether or not the radio's ALC is holding it back. If the RF envelope waveform looks like clean voice audio, that may be the culprit. But if it's flat-topped and clipped on peaks, the problem is a loss of gain...

They say third time is charm. Figured version 3 would be refined enough to sell. Top one is version two. Lower is V3. Decided the 7805T regulator ran a bit too hot with no heat sink. Moved it around so it can be bolted to the pc board surface in the same hole used to mount the board and the...

I have no road map of what's inside that radio at all. And if you find it, please pass it on here. A schematic diagram is my starting point when it comes to frequency mods. 73

Excellent hack! Bending the leaves is probably what caused the issue in the first place. 73

It sounds like a timing issue. The lever contacts should close the battery power before closing the audio-output circuit. A prior attempt to "adjust" the contacts by bending them can create this issue. Really sounds as if the audio output circuit is being closed before the battery circuit. 73

Biggest problem with DC on a pot is to have DC current through the wiper along with the audio. C10 makes sure the wiper has only audio passing through it. The DC current from end to end is a common design trick, and won't cause issues the way that passing DC through the wiper can do. 73

Just changing the 5 khz/10 khz pin on that PLL throws the synthesizer's arithmetic out the window. Gerhard's "funkservice" modules work as advertised. Pulling the PLL mixer crystal down one half channel tends to cause drift issues. 73

Power switch. Two lugs at the very rear of the control. Just bridge across them with a screwdriver tip. If it lights up, you found the fault. 73

They are 100k two percent tolerance resistors. The red color band is the percent tolerance for these parts. If each one has 350 Volts DC across it, that's 350 times 350, then divided by 100,000. That will be just under one and a quarter Watts of heat per resistor. They'll tolerate that, but...

Oh yeah. The 296. Sales slogan was "Twice as good as a 148". As if. 73

Good start. Eliminates a whole list of possible faults. There are a handful of slug-tuned coils/transformers that get peaked to align that radio. Most of them that are in the transmit chain are 10 mm square with a thin threaded ferrite slug inside. Many of them have a built-in capacitor that...

Umm, not to rain on anyone's parade, but the 1980 President Grant and the 1993 Uniden Grant XL are not the same radio. Similar yes, but the XL is a direct clone of the Philippines Cobra 148GTL. Uniden had been making the 148 until Cobra was spun off of B&K. The new owners hired RCI to build that...

Every year that goes by the MFC chips will get pricier. Kinda like 8950 tubes, but a bit less brutal. Nobody ever second-sourced those oddball chips. Only came from Motorola. 73

The keying circuit in a lot of amplifiers has a resistor in series with the RF input to the circuit's diode or diodes. A burned resistor in this spot reveals what happened. Lost track of how many times that resistor contradicted the "only used a barefoot radio" claim. 73

We used to call that the "moron fuse". 6KD6: 8950: 73

Not to mention the underlying design. 73

We learn from mistakes, not from successes. You stuck with it, and you won't have to learn that lesson a second time. 73