Monday, December 27, 2021

Hallicrafters SX-99 Restoration

This is a beautiful Hallicrafters SX-99 I restored. This was an easy restoration, as I started with a working radio. It needed a little of the typical cleaning of the tube pins and tube sockets, cleaning dial pulleys, cleaning and lubrication of the bearings in the tuning capacitors, cleaning and lubrication of the pots and switches, and a full alignment. These are such wonderful radios to restore, and great performers. Here's a few pics of the tasks, a finished video, and a few links to videos of it in operation.

A shot under the chassis after I recapped it.

A bunch of resistors and capacitors that were replaced.

Look at that chassis!! Beautiful condition for 1950's tech!

Original paint and lettering...very nice condition.

The paint is original, and while it has some scratches, its in great condition for a 65 year old radio.

All finished, aligned, and playing beautifully!

The Hallicrafters SX-99 in operation...

Here's a few links to other videos of it in operation during final check out in the workshop...

Video #2 -

Video #3 -

Video #4 -

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Video #7 -


Thursday, October 14, 2021

Slowing a Muffin Fan...

I was helping a friend to slow the speed of his 115vac muffin fan on an amp, and felt it worth sharing here.

A capacitive divider doesn't dissipate heat like a resistor. Using a resistor takes about 1k ohm at 25w and it gets HOT.

The motors in these little muffin fans are an inductive brushless shaded pole design, and the capacitor will take advantage of that as a divider due to reactance at 60hz.

I've used 1uF @ 200vdc, polarity doesn't matter. A non-polarized cap would technically be best, but I have _NEVER_ had a problem using regular polarized caps. It runs cool as a cucumber. As you increase the capacitance, the fan will speed up. You can add a relay to an amp to bypass the cap when transmitting and bring the fan to full speed while keyed, if you want.

This is a cheap and simple way to lower AC voltage on simple motors and other fully isolated loads.


Saturday, October 2, 2021

Hallicrafters SX-111 Faceplate...

I'm about to refinish the faceplate of a Hallicrafters SX-111 I'm restoring. I was hoping to retain as much of the original petina as possible, but there's way too much rust to allow me to sleep at night :-) This radio sat in a damp place many years. The electrical restoration wasn't difficult, but I want it to look good as well. I was able to locate the last 3 packs of Datamark white lettering in the new company owner's warehouse, so I'm sanding it down and starting over. 

Along with white, 1/8" tall lettering, there's a 1/16" wide white pinstripe all the way around the faceplate. I have a custom pin striping person that used to do work on my custom motorcycles, I'm going to try and talk him into that for me :-) Here's pics of the horrible face condition, just before sanding, filling, and priming work starts...


Friday, October 1, 2021

Portable Shortwave Antenna...


I stumbled upon this in a batch of goodies I just got. Had not seen one in years. Even has the little antenna coupler still attached and working :-)

This neat little antenna will be handy when travelling, vacation, overnight fishing trips, etc. Stretch it out, slip the coupler over the collapsed antenna, and you're in business! Someone mentioned something similar is available from C-Crane.


Monday, September 20, 2021

Cleaning Vacuum Tube Pins and Sockets

This is a short video explaining how I clean tube pins and sockets. While restoring and/or repairing tube rigs, I've found dirty/bent tube pins and sockets to be one of the leading causes of receiver noise and intermittent operations. 

 Dave WB4IUY


Sunday, September 19, 2021

Repairing a Hallicrafters SX-111 Knob

 There was a piece broken out of the edge of the knob. Considering the age of this radio from the early 60's, I decided to try to repair it.
I made a little form to follow along the inner curve of the knob with tape. A small bit of 5-minute epoxy was built up in this area and allowed to harden over night.
I removed the tape, and sanded the outer curve and edge of the knob to match. Using a Dremel tool with a cut-off disc and a jewelers file, I replicated the grooves in the outer surface. After cleaning, it's now ready for a little touch up color to match, once I get that mixed.



Thursday, September 9, 2021

Heathkit HW-32A, Post Restoration

 These are such cool little monoband radios! I've had all of them...the -12 on 75m, the -22 on 40m, and the -32 on 20m. They'll do around 100w output, are fairly compact, and have a great receiver. They are phone only, but with selectable sideband, I'm sure a little work could easily drop these in the digital segment of the band for those modes. This unit was pretty clean, but I washed the PCB and cleaned it up, anyway. The tube sockets and tube pins got cleaned, a shorted tube was replaced, caps replaced, some resistors were replaced, an assembly issue with the rear power connector was corrected, and the receiver was DEAD. I found a damaged I.F. transformer, repaired a burned winding, and it came alive. An alignment was performed to get her at peak performance. Wow, amazing performance from a 60 year old radio. Here's a video and a few pics... 


Thursday, August 5, 2021

Repairing a 10 meter monobander...

This is a President Lincoln 10 meter all-mode radio. These are often found on the CB band, but these are great little 10 meter rigs. The Uniden HR2510 is basically the same radio, but is only SSB & CW. This rig had a few problems, the first being it didn't work...there was noise from the speaker, and that was it. Turns out, the processor wasn't running on startup, and would take 3 to 5 minutes to start after power up.

This is a video of the initial checkout...

This is the processor board. The leaky caps are just above the top RH edge of the long processor chip that's close to my hand.

This is the bottom of the processor board. I've removed the bad caps and am prepping the board to install replacements.

A closeup of the processor board where the bad caps were removed. I also replaced the .1@50v electrolytic near the edge of the board, above my finger.

This video explains the issues with the processor and what was done to repair it...

This video shows the issues with the transmitter, and what was done to repair it.

This video shows the final cleanup and operation. These are great little rigs, and are also a nice rig for portable CW/SSB operation. They're very stable, and will work FT8 with no problems. AM is always a blast up on 29.000-29.100, and FM simplex is fun on 29.600.


Tuesday, June 22, 2021

Heathkit HR-20, post restoration

 This is a Heathkit HR-20 receiver I restored. I didn't get any pics during the process. The finished unit is great, quite a nice little receiver! I found issues in the wiring of the band switch, but otherwise it was operational from the start. I did the typical stuff to it...recapped, changed a few resistors, cleaned the tube sockets and pins, and gave it a full alignment. One of the unique things about this receiver, is where someone built the entire receiver power supply under the chassis, and mounted the transformers on the back. Cool work! I was very impressed with the sensitivity and overall receiver performance. Here's a video and a few pics...