Projects from the bottom drawer

2024
Nov
11

A Heathkit IG-72 Signal Generator - Wrapup, set-up, and final thoughts.

The device is working properly and has been buttoned up and put in it’s home on the bench. Here are my thoughts on how things went…

Thoughts

This unit was really the opposite of everything you expect from an old device. All of the passive components inside, like resistors and capacitors, were in good shape and don’t need replacing yet - although at some point it probably will require electrolytics. That’s for future me to decide.

This device really shows that you have to expect anything with an older device. Parts that don’t do anything other than hold a part can degrade and cause issues, especially when working with the higher voltages present in a vacuum tube device. I never would have though that a tube socket would fail like it did. Sure, they fail because the sockets themselves get weak, corroded, oxidized, etc. and make bad contact, but arcing across? That’s new to me.

I supposed it shouldn’t be unexpected, carbon tracking is a thing. The moral of this story is expect the unexpected. Especially when working with an 60 year old device that was built from a kit.

The complete timeline for this project

Notes on calibrating this thing.

The calibration - more of set up - for this device in the manual was written for a time when you probably didn’t have a Hi-Z meter on your bench, but pretty much everything is these days. Instead of following the manual, I did this:

Equipment required:

Oscilloscope
Voltmeter that’s accurate at 1kHz
Leads and stuff

1: Set the frequency to 1kHz, attenuator switch to maximum, and set the output level to ~5VAC RMS using your meter. Ignore the meter on the face of the unit for now. Connect your scope and meter to monitor the output.

2: Let the device warm up. Get it nice and warm. I put a cardboard box over mine to get it toasty. I think this is also how I got it to arc continually so be careful here - don’t set it and forget it. Heat is going to cause marginal things to fail. Check on the device every once in a while during warm-up.

3: After a few hours, when the device is warm, check the sine wave output on your scope. Slowly adjust the oscillator output control (the potentiometer on the inside of the chassis closest to the transformer.) Adjust the sine wave until you just start to get one of the tips cut off, and then back off a decent amount so you have a good sine. Note: These have decent high output with fresh tubes, you can probably back off a lot here.

4: Let it set for a while. You may need to adjust this sine wave a couple of times.

5: When you’re happy with the sine wave, adjust the output level to 5.00VAC RMS with your meter. Using the meter level control on the chassis (it’s the other potentiometer inside the unit,) slowly adjust until the device’s meter so that it agrees with your meter. I use 5V because it’s dead center of the meter’s scale.

You should be able to assemble the device at this point and have a clean sine with a reasonably accurate meter. Note, however that this meter isn’t calibrated at every scale and frequency, so it’s a best guess at all times. The manual even warns about this, so if you need a precise level always let the unit warm up and adjust with an external device connected.

After everything was said and done, I had an accuracy of about 2% with the selected frequency. I think that’s pretty good for a device from the late 50s.

Why did I choose 1kHz? Primarily because this is going to be used for signal tracing. You can choose whatever frequency you think is best for your purposes.

One of the things I’m considering is trying calibration at 10VRMS. That is, set the level control to the maximum, and then back the oscillator control off until there’s 10VAC on the external meter, then adjust the internal meter to follow. This should keep the system well within the linear range. That should be possible since the output is constant before it appears on the attenuator’s input - but there’s always the chance that it won’t oscillate at some point (frequency) because it’s lower than what the circuit is expecting. It’s going to require experimentation to see.

That’s all with this device. It’s been on quite a bit as I’ve used it for testing devices that are in the “keep or sell” pile. If anything else happens to this, I’ll post about it here on wereboar.

Previous part of this series: https://wereboar.com … 7-i-think-were-done/

Posted by bryan in 08:32:24 in General, Tech
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2024
Oct
29

I hit 1000 views on a post - Thank you!

I keep track of views on my project page - not because I get anything from it, as there’s no ads or monetization (and never will be!) - but because it tells me what people like, and it’s just interesting. Data like this is fun, I don’t know why.

For some time, a post about the Findlay hashtag#hamfest was the most popular thing, but recently a general tech post about not overlooking the power cords on a device during rework has reached the top spot. This morning, it hit 1000 views.

The post: https://wereboar.com … look-the-power-cord/

What does that mean? Not a lot, but I appreciate everyone that’s looked at that post - it means you’re finding things here interesting enough to do a direct click on it, as hitting the post in the feed doesn’t increment the view counter.

Thank you for hanging out and spending some of your time with me. If there’s something you’d like to see more of, I’d love to hear from you. Connect with me on LinkedIn, or catch me on Mastodon.

Posted by bryan in 06:24:49 in General
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2024
Oct
21

An Eico 145 Signal Tracer - Wrapup and final thoughts.

The signal tracer rebuild has been finished and happily amplifying sound again. What’s next? Here’s some thoughts on this device, and the rebuild process in general.

On the rebuild process:

1. Research the device.

Looking the device over and gathering things like schematics and assembly guides are a necessary first step, but don’t overlook the fact that these devices have been out there for decades. Plenty of people have had them in their possession, and there’s plenty of after the fact info available. Modifications, parts swaps to increase life, general deep dig things that may assist you in putting the thing back together. Read everything you can about the device before starting.

2. Some other tools you may need.

One of the greatest inventions I have on my bench is a tool called an orange stick. It’s not orange in color, but made from (traditionally) orange tree wood. It’s similar to the sticks that nail salons use in that it’s a double-ended stick with wedge-shaped ends - except that it’s longer. These are a soft wood that won’t mar parts, and can be used to push wires and wire-ends around for forming, as well as a soldering block for parts close together. They have a million uses. I highly suggest adding a pack of these to your tool kit.

Also, don’t be afraid to have more than one soldering iron on your bench. I regularly have my trusty 30W Weller, but keep an 80W unit handy when doing chassis work. You may find that having multiple wattages, multiple tips, or even multiple size units on the bench to be of use. You may even find a small butane torch to be useful here. Don’t limit yourself to just one.

3. Parts.

When you’re ordering parts, don’t use the crap you find on Amazon or eBay (unless you can verify it’s of known pedigree.) Get known parts from one of the supply houses. You don’t need to use the absolute top-tier part (unless you want to!) but get a good part. Always get an extra or two as well, in case you break something. It happens! Don’t go crazy buying 100s, but if you need 9, get 10 (and possibly a price break.) Be aware that some parts may have inductance (wire-wound resistors) and you want to avoid that kind of thing unless replacing like-for-like.

4. Be aware of voltages and values!

Capacitors are easily rated by the nomenclature printed on the part. Get at least the rated voltage and value here, but don’t go nuts. You don’t need a 1000V part where a 400V part was specified, but if all you can get is a 500V part, that’s fine. You’re not going to get the exact same values today for most of the stuff (except resistors) so don’t be afraid to go up a little in value. A 22uF part will easily replace a 20uF part in the power supply without issue - just don’t fall into the “more is better” trap because it’s not. Stay close to the rated design specs.

Resistors are a special case. For the most part, the 1/2W resistors used then are easily replaced today. However, be mindful of the voltages - you can be working with 300, 400, 500+ volts here, and parts need to be rated for the working voltage of the circuit. For example, if you have a resistor that’s rated 2W but it’s 2 inches long, then it’s probably a higher voltage device. Using a resistor rated for 500V in a 100V circuit isn’t going to hurt anything.

And, always remember you’re working with line and higher than line voltages here. Don’t be afraid of it, just give it the respect it deserves.

5. Grounds.

Grounds are important. Always make sure your contact points on the chassis are clean, and use washers that dig into the chassis if you can. Soldering those grounds to chassis for a good contact point will also work, but make sure you get a good connection otherwise oxides will build up and give you more grief than you started with. Good fluxing and a clean shiny spot for soldering is important here. Scotchbrite (plastic “steel” wool pads) is your friend here!

6. Signals.

It’s always been good practice to lay your filament and AC wires right on the chassis if possible, and to keep your low-level audio away from those, if possible. Keep it short and covered.

7. Don’t be afraid to modify!

Unless it’s of vital importance that a circuit be laid out the way the manufacturer did it, don’t sweat it if you see a better way. Add a terminal strip to bring parts out from hotspots. Add holes to mount new parts instead of trying to replace the exact old ones. Add a fuse. The manufacturers probably tried to work the assembly to use the least amount of extra parts, but you can take whatever luxuries you need.

8. Be mindful that you’re not the first owner.

There’s probably going to be modifications in the device. There may be added or missing parts. It may be that someone was trying to make the device do something else. Note these modifications before you begin, but don’t necessarily use them as a guide for rebuild unless you can see that it was trying to fix something.

9. Don’t be in a hurry.

The important advice with any kit. Take your time to lay out parts and wires. Check things as you go along, and check it all again when you’re done.

My thoughts on the device itself and rebuilding it…

This is a fairly simple device in terms of operation. A power supply, a preamp, and a power amp. Not much going on here, but there were still some modifications made.

The 6K6 power output tube is run electrically hot in these, about 1W above rated specs according to what I’ve read and calculated. It was suggested that the cathode resistor, R5, be increased from 470ohm to 1kohm. I did so in this rebuild. C10 was missing on my device for some reason, and that was added back in. R5 is the resistor that provides current for the cathode, and C10 is a bypass capacitor to help improve fidelity of the amplified signal. It’s possible that C10 went bad at some point and was removed, as the device will operate just fine without it. I couldn’t see any evidence that it was ever there, however.

I’m not a purist, so I didn’t care how the power supply turned out. The old capacitor was discarded and two new parts were laid in it’s place. I decided to use a 500V non-inductive 25W aluminum resistor here, bolted directly to the top of the chassis, with the capacitors going to a ground also on the top. That probably offended some people, but I need functionality here, not a beauty contest winner. The reason I used the aluminum resistor is because it’s non-inductive, and was available to me.

Terminal strips were reused where possible, with new ones added. These allowed me to space the parts out more, which should help life in the terms of heat related death. It also allowed me to use two back-to-back diodes in the filament circuit to cut down on the voltage, since the device was designed to run on 110 - not the 125VAC we commonly see in the USA these days. Where something was grounded, the tabs for the terminal strips were soldered directly to the chassis to provide a good ground. It’s not the prettiest thing, but who cares.

Last, I had to remove and correct some of the modifications to this device. One of those nasty Amphenol microphone connectors on the front panel was removed (and needs to be filled at some point,) and the audio output transformer was bolted down. The audio transformer in the device didn’t fit the holes provided (device was narrower,) so I don’t know if this was because the original part was bad and was replaced at some point, if the chassis was drilled wrong, or what. A new hole for the transformer and a terminal strip to provide ground for the power supply mounted in the old hole fixed both those.

The only other thing is deciding how to fill the front panel hole. I could use a BNC connector, but since this probably will never see IF frequencies, do I care? Originally, I though about just plugging it with a plastic plug I had laying around, but I’ve kind of warmed up to using that hole as a ground tie point, or maybe just a tie point in general that’s not connected to anything internally. Who knows at this point.

During the final check, I discovered two errors.

The first one was I put a 510k resistor where a 10M should be. I think I know what happened here - I had a 10M there, but didn’t like the way it laid. I pulled it out, saw the blue stripe, and looked at the blurry schematic. I then assumed it was 510k and put that back in place. It’s been long enough that I forgot I actually bought 10M parts, so this was completely my fault.

The second was the b+ connection to the junction of R3/R4 wasn’t laid in. I remember looking at this and thinking I already had too much crap on the one tie point, and intended on going back later to put this in. “Later” just happened to be the last step, so this is both my fault and me claiming I meant to do that.

There’s still that hole in the front panel. I think I’m just going to go with my original thought and plug it.

But…that’s it! This device has been well used, looks like it’s Seen Things - that’s part of the charm of this device. It’s rusted and has spray paint on it and some scratches. It’s a piece of equipment that’s worked it’s entire life, and it’s ready to do it again. I’m not interested in “restoration,” I want the device to look like it does. So…crank up the 1KHz and let’s get some radios repaired!

Recapping the journey (and the device!)

Purchasing the unit at the 2023 Breezeshooters Hamfest in Butler PA.

It was obviously a kit unit.

Some cleanup on the physical parts of the device, then removing everything.

All the parts are out.

Putting things back in, one part at a time.

It lives!

And, we’re done.

The entire series from start to finish:

It’s been over a year since that first evaluation, thank you for coming along on the journey. I think the next device will be the signal generator I picked up at the Scioto Valley hamfest. Stay tuned for more good junk, I mean equipment!

Previous part of this series: https://wereboar.com … art-8-and-were-done/

Posted by bryan in 07:03:11 in General, Tech
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2024
Oct
19

NTE Electronics is gone.

NTE, or New-Tone Electronics was probably a name familiar to anyone that has been in the electronics business for any length of time. Much like RCA’s SK line, NTE made and self-packed replacement transistors, resistors, and other parts for the replacement and hobby industries, and had folded the Sylvania ECG line into itself some years ago.

According to reports, the company was sold in 2022 to owners who mismanaged the company and drove it into bankruptcy.

This removes the last “replacement” company from play.

A company called Vetco Electronics has picked up some of that lineup, packing parts using NTE/ECG’s numbers, so all is not lost. I assume they’ll use the same foreign sources that NTE used, but who knows. You can find their announcement on the matter here: https://vetco.net/bl … -09-11-14-39-26-0700.

So long NTE. We’ll miss you.

Posted by bryan in 17:40:40 in General
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2024
Oct
14

email services for pygg.xyz have been terminated.

When I migrated this blog from pygg to wereboar, I left a few of the services running on pygg.

One of those was email - I didn’t need it, but I left it alone for whatever. In retrospect, that was a bad idea since my host refunded unused time, but that’s another story…

If you’re emailing any pygg.xyz addresses - and the logs revealed there were quite a few recruiters still banging away - you can remove those addresses from your lists. I don’t plan on using that domain again, and will simply let it expire in 10 years or so if no one wishes to purchase it. In the meantime, pygg will redirect to here - assuming the redirects work. I’ve noticed there’s some BS with that happening, but it seems to be stable for now.

Pygg.xyz is for sale, send me a message on LinkedIn or Mastodon if you’d like a short domain name, cheap.

Posted by bryan in 11:58:44 in General
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2024
Sep
28

Salary is confidential? Your response should be thanks, but no thanks!

Some years ago, I was contacted by a company that manufactured building products, as well as electrical devices to handle said building products. This was in regards to a technician position - more of an engineering tech - at the company’s headquarters. They’re just a shade under 2 hours from me, travelling on some country roads - there’s no way I could live here and drive there.

This was kind of an odd process, we had a phone screen and an on-site interview first, and a couple weeks later they asked me to fill out some online paperwork - applications and some assessment thing. During this time period, I had been unable to find out any information about the pay rates for the position. When we got to the hot and heavy part, I asked.

You can see the recruiter’s response and our email chain in the image.

I was told the salary range was confidential, but the recruiter could advise me based on my current salary if we should continue. I provided said information.

The eagle-eyed among you will notice the recruiter never really affirmed that it would be worthwhile to continue. Just that they had reviewed it. I didn’t notice that at the time. You’ll also notice I made the mistake of not saying what it was I wanted.

Did I get offered the job? Yes. Was it worth the time? It was a little more base, but was a net loss when I factored in medical and other items that my current employer gave employees at the time. I had to turn it down.

The recruiter and interview team called me. They wanted to know what they needed to do to get me in the door. I said “it’s the money.” It’s just not worth the few cents more you offered. You know where I live, you know what I make, you know I’d be leaving everything behind and essentially starting over with a higher-skill job. Make me a real offer.

Well, that went nowhere, and that’s the last I heard from the company.

Now? If I couldn’t get an answer up front about that salary range, I’d simply thank you for your time. It’s confidential? No, it’s not, and I’m going to be running away from your company.

It taught me to get all the information up front. If someone tries to play games and hide that info? Turn around and leave. That’s all.

Posted by bryan in 11:14:09 in General
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2024
Aug
27

It’s interesting how old data just keeps kicking around.

How many of you remember the 2021 LinkedIn data breach?

While not really a “breach” in the traditional sense of the word, it did result in some party scraping the public data of many, many profiles - the one I had at the time included. I’ve since deleted that profile for this one, and quit using the associated email address. I don’t want to give up that email address because it’s fairly desirable and attached to some other services I can’t migrate, so I keep it around.

I check that address every so often, because I know some people that I might like to talk to - and have not for a long long time - may still have it. Much to my amusement, offshore recruiters still email it, talking about how they just found my profile on a job board I don’t use and would I like this 2 month contract job in California for $22 an hour?

However, today was a little different. I’ve received emails from a few people contacting me at that address about how they just found my profile on LinkedIn, and because I was a successful business owner, would I like to consider franchise opportunities? I received one of these today, after a long dry spell without one.

They, of course, didn’t find my profile on LinkedIn using that email address, because it hasn’t existed since 2021. That tells me that the data from the 2021 breach (and possibly the 2016/2012 breach) is still out there, and being sold as fresh, useful data.

I politely emailed this guy and said that I was sorry but he bought bad, stale data, and asked him to remove me from his list since there wasn’t a business at that address, never was, and I was not interested in starting one.

I’ve had marginal success doing this. One guy seemed really confused until I found out where he got the data, and I told him why he had that data. One got very angry with me - that’s not the way to sell yourself. Most never reply. I never hear from any of them again, so I assume they get the message - but if not, it’s on them.

I hope this guy takes the hint. If he asks for more information, I’m happy to share.

What’s the moral of the story? All those “leads” that people are trying to sell you may not be what they seem. Pay attention to what you’re buying, you may be buying the last guy’s garbage packed up all neat in a gift box!

Posted by bryan in 07:15:14 in General
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2024
Aug
11

I’ve added a mastodon feed to the blog.

I’ve had commenting here off for some time, mostly due to the spam problem. Flatpress is a great system, but all comment platforms, unless heavily moderated, are spam magnets.

However, I wanted a way to communicate with people that may be reading this blog. I’ve had my LinkedIn profile connected for some time, but that’s not an accessible platform for most. Mastodon, however, is.

Mastodon is one of the twitter-likes that came out of the old Gnu Social era. It’s exactly what you think it is, a feed full of short posts by multiple people, and you can follow and interact with anyone that’s a part of the “fediverse,” a loose-linked conglomeration of various servers and people.

That’s not to say Mastodon doesn’t have it’s own issues, the originator of the system has some hangups that prevented conversations linked to other servers because he didn’t like the content, and it certainly has a very political leaning if you dive into the main feed. That’s not what I’m here for - I simply want to post my weird electronics and give people a way to go “Where did you get that thing?”

If you’d like, check it out: https://mastodon.social/@wereboar - not everything here has been mirrored there, but going forward - it will be.

Thanks for hanging out with this little pig, and I’ll see you at the hamfest!

Posted by bryan in 09:45:48 in General
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2024
Aug
7

Have you ever wondered what’s inside of that device?

Worry no more. With the help of Google Translate, you can finally see what’s actually inside that cheap Chinese solder pot you bought from AliExpress.

That magic “Heating Stuff” - it’s like the smoke in resistors.

Posted by bryan in 08:28:46 in General
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2024
Jul
29

A recruiter once told me that a company was a poor choice. They were right.

A recruiter once told me that a company (that I had asked about) was generally known in the local industry for wanting to pay substantially under market - trying to be as cagey about it as they could. His comments about the place were substantially more colorful, but that was the gist of the statements, along with a “probably not going to be worth your time.”

The person telling me this had no connection to the company, so I put the info in my files, and thought that maybe they just had a bad experience with the place.

No, they were correct - I had a few offers to interview with this place over the years, and the pay for skills desired was very poor - probably about 1/2 to 2/3 of what others were paying. I turned down the few contacts I had with a “Thank you, but there’s nothing about your offer that makes me want to pick up and move across the state.

The last contact I had with this company, the person contacting me became somewhat (not really) angry that I refused to even consider the position. To be fair, I did have an online profile that stated a range of pay I was interested in, but this also was posted with the caveat of being for local positions only. Any movement would require reassessment of those rates. When I pointed this out, the person passive-aggressive told me “Oh, ok.” That was the last time I heard from them. I’ve since taken a look at reviews on job sites, and those suggest that things have not changed - or even increased a whole lot, if at all. There’s a lot of talk on these reviews about the complete lack of awareness and organization within the company.

I appreciate that information to this day. When I’m told there’s something not right about what I’m looking at, I make a point to at least investigate the complaint on my own. Even if the complaint seems to be unfounded, I still keep that in my back pocket.

Posted by bryan in 07:12:09 in General
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