- 2025
- Sep
- 8
The 2025 Findlay Hamfest
The Findlay Radio Club Hamfest is usually a pretty decent show. It’s been shrinking somewhat over the years, which is unfortunate, but there seems to be a lot of ‘fests in Ohio these days. Perhaps that, and the general aging of the population / equipment getting older and not having more made is starting to affect who and what shows up. No idea, but this years show was probably about 2/3 of the size of the first one I attended years ago. I may put this one on every other year or so…
That’s not to say there wasn’t good stuff to see, I usually bring home way too many things from this show and this year was no exception. There was plenty of good stuff to see, and it was still well worth the trip.
I did notice that prices seem to have come back down again, after the exuberance of the first half of the year. They’ve come down a lot, to the point where I noticed a certain piece of equipment that would make a good economic indicator. More on that later!
Regardless, it was a lovely day for the show and I took a number of pictures of interesting things:
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There are a couple more shows this year before the season wraps up, including a new one in Pennsylvania that I’m going to check out. Stay tuned, and I’ll see you there!
- 2025
- Sep
- 3
A Workman Electronic Products N71-067 Power Supply - The Repair
After poking around in the power supply for a little while, I believed that the LM723 was probably bad. However, something didn’t set right. A few more checks and there it was - while the output transistor was fine, the driver transistor area had a substantially lower resistance than the surrounding parts would suggest. I pulled it out, and for all intents and purposes it’s shorted C-E.
That’s an easy fix, it’s a S8050 transistor. I had to place an order for some other things, so I ordered a batch of transistors.
It was easy enough to install
However, since the LM723 probably was quite stressed from this failure, I decided to replace it as well. I just cut it out and pulled the pins from the solder pads, then removed the solder with wick. That 1970s phenolic board smell! It’s going to get socketed just in case. (Finding these in DIP is getting kind of difficult!)
Since the big filter was quite old, I replaced it as well. Here’s a shot of the completed and re-installed board:
And, it works!
So what all was replaced?
The S8050 driver transistor for the series pass regulator.
The LM723 Regulator IC
The main filter capacitor.
I did dial the output back a little to 12.8VDC, just because I want this on my bench for other things.
A relatively easy repair, but there’s not much in this thing to go wrong. Next up is starting the actual rebuild on the Heathkit AG-7, stay tuned!
Previous part of this series: https://wereboar.com … /[url]
- 2025
- Aug
- 13
A Workman Electronic Products N71-067 Power Supply
I picked this up at the Columbus Hamfest, mostly for the 1970s vibe it has. I love that round meter.
The inside is what you’d expect from this kind of device.
It looks to be a standard (reference) LM723 circuit with a series bypass transistor to step the current up. That’s also expected, it’s not like there was much else at the time. Note the 1977 date code sticker and the bread tie for the wires!
I can’t find a lot on this company. There’s one of the same name, but they are (were?) in Delta, Ohio - not Florida. Regardless, their website is broken and has a last date of 2004. There are a few other references here and there, but nothing concrete. I have to assume that this variant went away after the CB era ended.
Does it work?
No.
It’s supposed to be 13.8VDC, not 26. That’s probably the max that the device can put out, and the pilot lamp is just screaming here.
So what’s wrong?
The big transistor is my first check. It’s somewhat shorted B-E, but it has a resistor across those leads. The only way to actually check it is to pull it out - which will need to happen if the board is accessed, seeing as how the heatsink covers traces. The transistor checks fine once out of the circuit.
There’s a small transistor that acts like a buffer driver for the big transistor. it’s fine. None of the resistors are exhibiting any issues, so that just leaves the LM723. There’s a small adjust pot, and it does nothing, so - yeah - this chip is probably bad.
Those are cheap, so I’ll pick up a few.
It’s actually surprisingly difficult to find DIP parts these days, so I turned to an old friend - Jameco. They still stock this kind of stuff, and if you order from someone else they’ll probably ship from Jameco. Check them out here:
Jameco Electronics https://www.jameco.com/
I ordered some replacements for all the semiconductors in this device at the same time, so we should be good.
As soon as they arrive, I’ll pull the old LM723 out, put a socket in, and slap a new chip in there and see what this does. It probably will just work.
Stay tuned!
Next part of this series: https://wereboar.com … r-supply-the-repair/
- 2025
- Aug
- 13
A Knight “Space Spanner” regenerative radio.
So, this item literally followed me home from the Cincinnati Hamfest.
Seriously.
I was talking to a guy about a Simpson 260, and he asked if I was interested in a radio. I said no, I had an old coffin TRF in the queue. He picked this up and handed it to me and said “If you do something with it, you can have it.” I said “I promise it will go on the bench, but nothing more than that.” Deal done.
So what is this thing?
It’s a radio from Knight (Allied) called the Space Spanner. It covers broadcast and shortwave bands. It’s based on an old design called a regenerative receiver - essentially, the RF is re-amplified before being detected, so hopefully you get a stronger output with less active components. It’s cost-reduced before cost-reduced was a thing, and was obsolete by the time this kit was made. It was cheap, however, and allowed a new kit builder to get something and cut his teeth on it for not a lot of cash.
It’s in fairly poor condition, and probably sat in a garage after the builder moved on. Everything is there, however, so that’s a plus. The cabinet is a plastic-wrapped wooden case made from plywood, and is actually a fairly nice cabinet. It’s very dirty, however - scrubbing with 409 barely made anything except blackened towels from the dirt. (I’ve read the cabinets for these were made by a luggage company.)
Inside, the chassis shows signs of being modified over the years. There’s a giant capacitor stuck in there, and it’s attached to the final point on the original filters. I have to assume the original is bad, and the person just stuck a 100μF in there because that’s what they had, and it worked. I’ll know more on that, later.
The antenna terminal is loose and the plastic portion is locked open. That’s no big deal, and a pair of needlenose fixed both the loose screw and the locked connection. Tubes are all there, and most capacitors are disc. I don’t see any real reason for concern here, so into the isolation transformer it goes. Probably should dim-bulb this, but eh…I like living life on the hot edge.
I got a little noise out of it, but nothing else. A tube wiggle made lots of noise, so I turned it off and gave all the pots and tube sockets a few drops of DeoxIT. After a good cleaning, I put the tubes back in…
It came right to life. After messing with the controls, I was able to get most of the strong local AM stations with a short piece of wire. So, the device is working, which is pretty cool.
So, what next?
I think I’m going to do a basic restore on this - new resistors and a new filter. There’s not much else, all the other parts are disc capacitors save the ceramic cap at the top, and it looks good. I do need to figure out what’s up with the antenna control, it seems like those spacers are too long and the knob won’t go on properly. I know it’s the correct knob because it both matches what is on the rest of the unit, and other images show this knob. Maybe some shorter spacers are in order, who knows.
Anyway, this is a really cool piece of old tech, and deserves a chance to live properly. Stay tuned, more on this unit coming later, rather than sooner!
Next part of this series: Coming sometime.
- 2025
- Aug
- 13
Photos from the 2025 Cincinnati Hamfest
I’d never been to this show, so I wasn’t sure what to expect. Turned out to be a good local, a long row of vendors with some more in a building. We ended up wandering around for a couple hours, looking at everything twice. A few odds ‘n ends went home, including some freebies, so it turned out to be a good trip.
Prices at this show were variable - some were selling things for more than new, others had what I could consider to be accurate prices. Unfortunately, the down in the dirt prices of a few years ago seem to be gone. Hope you got what you wanted then!
This is what I saw at the show:
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This will probably be a show I go to if there’s time, seeing as it’s about 2 hours away. Next show is the Findlay hamfest, which is always a good show (assuming no rain!)
See you there!
- 2025
- Aug
- 4
The Cincinnati Hamfest - August 9th 2025.
I’ve never been to this show, so I can’t really say what it’s like - but it’s not that far so I’ll take a trip and see. If there’s anything good, I’ll have a lot of pictures for you. It’s at the Clermont County Fairgrounds in Owensville, which is a suburb somewhat to the east of Cincy proper.
Cincinatti Hamfest
Clermont County Fairgrounds
1000 Locust Street
Owensville, OH 45160
August 9
8A - 2P
Admission: $10 (you can pre-order tickets)
https://cincinnatihamfest.org/
See you there!
8/11 Update - I did make it to the show, it was a little one but I still saw some good stuff. Pictures coming ASAP.
- 2025
- Aug
- 4
Photos from the 2025 Columbus Hamfest
The show in Columbus, Ohio is always a surprisingly good one. Other than the few years that it threatened rain, it’s always presented a very good selection of things to see, and a lot of vendors. This year was no different. Prices at this show were what I would consider more reasonable, so it was easy to spend a few bucks.
I limited myself to a few small items and some books, but there was plenty for everyone. Here’s what I saw at the show:
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The next show (this coming weekend) is Cincinnati. I’ve never been to that one, so it will be interesting to see what it’s like.
See you there!
- 2025
- Jul
- 22
The Columbus, OH Hamfest - August 2nd 2025
The Shriner’s Hamfest in Columbus, Ohio is happening August 2nd. This is a small, local show, but it’s always been good for something decent - be it a project device or simply something unique. Since it’s my local show, I always make a point to attend. As always, I’ll have pictures shortly after the show.
Columbus (OH) Hamfest
Aladdin Shrine Center
1801 Gateway Cir
Grove City, OH 43123
August 2
8A - 1PMish
https://aladdinshrine.org/hamfest/
See you there!
My 2025 hamfest list, with pictures: https://wereboar.com … mfest-and-show-list/
- 2025
- Jul
- 8
An easy fix for this GE Microwave Oven.
As the great Monty Python’s Flying Circus once told us: “And now for something completely different.”
This is some unknown model of GE Microwave. It’s from the early 1990s, and was originally installed in a camper van that a relative is scrapping. Since the unit didn’t get used a whole lot, I took it home thinking that it would work great for an office microwave. There’s probably a model number on the information packet taped to the cavity, but I didn’t care enough to open the now-fragile paper envelope.
Well…not so much. This is what I saw when I plugged it in:
There’s a lot of things this could be. Disclaimer: I used to work as a factory depot tech at GE, and saw this thing’s cousin boards (we just did the controls, repair centers or field techs did the actual unit.) Depending on how much a replacement board cost, some came back to the depot, some just got a new board with the the tech being instructed to toss the old one. As I don’t recognize this particular configuration, this was probably in the “toss it” category.
Background
This particular unit was branded GE, but was made by Samsung. To the best of my knowledge, GE didn’t make any of their own microwaves. (Perhaps a few early ones.) They had other companies make them - in particular, Matsushita and Sanyo did many of the 1970s and 1980s units, with Samsung picking up in the mid 80s and going into the 90s, when I left the company. There were a few others in there, including one Mexican-made unit that was built on GE Coshocton circuit board.
Samsung had the lion’s share of these devices, manufacturing, packing, and shipping the units in GE-marked boxes right to the warehouse. GE never saw or touched these things.
This particular unit was very cost-reduced. GE had been pushing Samsung hard, and it showed in certain components on the board. Displays went from Japanese itron and Noritake oil-based paints to cheaper water-based paints (that’s why you got units where the fluorescent displays were bad after a year,) PCB itself was the absolute thinnest thermoset resin that would crack if you looked at it wrong, and relays - oh boy, these were absolute crapola. No more good Aromat relays, these were cost reduced to the point where someone saw a relay once and said “I can do that!”
Relays
There are, at minimum, a couple of relays in most microwaves. Some used triacs instead, but relays are cheap and isolated. This particular unit has two relays, one for the magnetron and one for the “everything else.” It uses these relays:
The previous generation of relay was typically Aromat or Omron. These were good Japanese relays with contact surfaces that were machined in some way as to suppress arcing and extend the life of the unit, as these were often switching 10A. Not these junkers - they were simply copper buttons on an arm, and they would arc. It wasn’t unusual to get a control board that didn’t operate - it was stuck on or didn’t work at all. The relay was usually melted closed, or had so much carbon on it (and melted surface area) that it wouldn’t close anymore. I don’t have exact numbers, but we went through these relays like they were free cookies.
My boss, the shop manager, asked the project engineer about these relays. Project engineer said that they received several samples direct from Samsung and they worked great, he wasn’t sure why they didn’t work here. Boss asks if he bought them through retail channels - no - so Samsung probably hand-picked these test units. We’d constantly get ones with different names on them. Young Reem, Star, DEC, etc…I remember seeing at least 6 types, so who knows where they were actually coming from. They just looked and felt bad.
What does that mean? Any microwave that used these was born to fail. This one, fortunately, has limited hours and a lower power magnetron, so the contacts haven’t blown themselves apart. Yet.
Diagnosis
When I first plugged this thing in, it’s “uh-oh.” There are several problems that could cause this kind of display, including:
Bad resonator (clock)
Bad microcontroller
Bad power supply
Bad soldering
Cracked circuit board
Something in the display/keypad lines
These units were better at soldering than some of their earlier brethren - those were terrible and you’d often get cracks in the board, cracked solder on the transformers, bad solders on the micro and resonator, or no-solders. I can’t count how many no-solder units I got on my bench, with a couple being that way because they had enough flux on them that the board was completely gooey with it.
I almost immediately eliminated the resonator and micro because I could see the scanning of the diplay in the camera’s preview. That means it was still driving the display properly, and not just in a locked up state.
A quick look and the board and soldering on this one look ok, including the resonator. I was getting ready to check power when I noticed the ribbon cable for the keypad just didn’t look quite right. I undid the connector, pushed it around a little, and closed it.
The keypad and display can share lines on the micro, so if one is bad the other can be bad as well. The keypad in particular is a ribbon with carbon contacts that slides down into a mating connector. The connector then has a plastic blade that goes into the body and pushes the ribbon against the contacts. These connectors are garbage, they will break at their hinge and change shape slightly over the years. As this sat in a camper van, hot, cold, hot, cold…the ribbon wasn’t seated properly.
This isn’t the best shot, but you can see the ribbon coming around from the front of the keypad into it’s connector. This one didn’t break when I opened it(!)
It doesn’t take long to test, so I plugged it in and was rewarded with the power-fail all segments on display. Keypad works now, I was able to set the time:
I put it back together, gave it a test, and it made much happy hot water.
That was an easy fix - I was worried some unobtainable part (like the mask-programmed microcontroller) was dead, but it’s not. Off to the office with you!
- 2025
- Jul
- 4
This is Project’s 4th anniversary.
July 4th, 2021 is when I opened this as pygg.xyz and transferred some of my old blogger.com content here.
I don’t have anything special to present except thank you - I appreciate all of the views I get here, and I hope you’ve found something of interest over the past 4 years.
I have a number of devices and shows in the works, please check back soon.