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?Curious if your bad experience was with a switching or linear wall wart??? Dan WB4GRA

I will no longer use any wall warts to supply DC to anything that’s sensitive. I learned the hard way with one of my old Trac CMOS keyers. I had to replace all eight chips and a transistor when the

Jeff, No spec but the stabilizer has four CMOS chips and one LED with the LED drawing the most current.? So, 15-20 mA.? Either a 78L10 or 1/2W 10V Zener should be fine.? The 78Lxx devices are good

I'll take the filter. PM the details off line. Tnx.

As to DC ?wall cubes, test first. ?Some of them have high onset voltage until the regulator kicks in, and some of them are prone to RFI altering the output voltage.

Bob thank you again for your thoughts. The potentiometer did fail completely so I'm on the hunt fo a 15M linear potentiometer. Best I've found so far is 5M from mouser who should be fine. If anyone

Good point. The 78L24 is a known failure point. Also C2108, which causes strange problems when (not IF) it fails. Replace it if today is a day that ends in the letter Y. The -5 will be around -3 to -4

Paul, what's the current requirement for that VFO stabilizer board? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com

Also marketed as LED drivers. I have an adjustable one driving the +20v PLL power source in a Uniden scanner as the original dead chip was unobtanium at the time. It's been working well for a couple

There are LDO versions of the 317 series. Fixed regulators can also benefit from a protection diode. The risk is if the input voltage falls below the output voltage. Diodes are cheap. I have a

Maybe. It is a hermetic I/O pin. If you want it for $25 it is yours.

I had this same problem. Found the core fell out of the T2101 transformer on the power supply / regulator board. Found it in the bottom of my TR7. Tied that back in place and all was well. Check that

Nigel, I would like to avoid switching/bucking DC-DC regulators. Sometimes they seem fine only to discover a spur or two some time after a mod is made. Just me, but I think all vacuum tube gear should

I have a used one I can let go for $50 if anyone still needs one.

Paul I have not read the other suggestions, but two come to mind 1. Can you unground one side of the AC for heaters. Normally it is a twisted pair. I used a bridge to pull down the heater voltage on a

Jim, I don't believe the 317T is a low-drop-out regulator. There won't be much In-Out margin on the 12.6 VAC string during a brown-out condition with half-wave rectification. It also requires (or

*** That sounds about right. And now that I remember, I used a 1/2 wave voltage doubler running off the 6.3VAC. - Jerry, KF6VB

Check the RV7 Jones plug and socket, front panel Fixed buttons, and "Molexia" on the other boards. 73 -Jim NU0C "K6OXN Bob" <bobk6oxn@...> wrote: -- 73 -Jim NU0C

Even better, use a 317T regulator *with recommended external caps*. Better specs and you can set the voltage to exactly what you want. 73 -Jim NU0C "jerry-KF6VB" <jerry@...> wrote:

Jerry, You probably used a 78L12? Paul, W9AC