- 2023
- Jun
- 10
Dayton purchase: An HP3440 NIXIE DVM
One of the things I keep an eye out for is NIXIE equipment. I have a few pieces in service, and as these devices age they are getting harder to find. People such as myself buy them for parts and spares, and godless heathens destroy them for the tubes so as to build clocks. It’s not uncommon to find an empty chassis where all the boards were discarded when the tubes were removed.
Fortunately, this wasn’t one of those. Cosmetically, it was in ok shape. Covers were all present, feet and bail were there, it looked it’s age. Wood screws holding the bottom cover on suggested someone had been in it and lost parts, so that was taken into account. The vendor said that it worked, but examination and experience said it probably didn’t. I was right.
The aforementioned screws told a story that someone had probably opened it, let it set, and someone else hastily tied it up for sale. It had several non-factory features installed, including both the clogged-with-mud input terminals, and the rust-onna-nut package for the plug-in module. This thing probably sat in a barn or garage for a while.
As Shango066 says, the first thing you do is look at the device thoroughly to note anything unusual. The inside had several things to see. The device had about the level of dirt I’d expect, although it’s not really that old for one of these units. Date codes on capacitors suggested this had been made (or repaired) at some point in the early 80s. That it didn’t have ICs for the driver cards suggests it’s not one of the last ones, but it’s getting close.
The first thing of note was the missing fuse at the top of the device. This wasn’t as much of a concern as you’d think, as it fed the recorder output instead of being a fuse for one of the power supplies.
The plugin module had some interesting things going on as well. One of the cards was not seated properly in it’s slot - this could be from vibration or other mechanical stress, so that was simply a matter of pulling it out and re-seating it properly. The card was slightly warped, so it had been like that for some time.
The most interesting thing here was the two orange dry electrolytics in the middle of the module. This most certainly isn’t factory, and as they were just hanging loose and kind of tied together. It’s pretty obvious this isn’t a factory part - if you hadn’t guessed that already.
I don’t know that you could get that style of capacitor in the 80s, so those may have been hanging around in someone’s parts bin, or may have even been rescued from an old television set before making their way into this device. If I plan on putting this module into service in one of my other devices, it will need to be repaired correctly.
Note the ultra-precision resistors present in this module. 10.114k (!)
The bottom wasn’t as bad, but still showed some work.
There was some dirt along the wires indicating it had been in use for quite some time, and one of the clamps was broken. I’m not sure if this was due to age or someone moving wires frequently, but it’s not that big of an issue. The big takeaway here is the rat’s nest in the upper left hand corner of the unit. The string ties had all been removed and this bundle had been poked at numerous times. Nothing was broken or showed signs of insulation damage, so I ignored it and moved on.
So…what’s actually wrong with this unit? As you can see from the first picture, almost all of the tubes light up. The second numeric tube has some bad segments, but that’s to be expected. This unit simply didn’t DVM. Normally, the neon lamp to the left will flash, one flash per read. This one did not, it was like it was in hold mode. You could mess with the 8000 button, and the sample rate control to get it to manually change, but it was not performing those reads automatically like it should.
Often times, that will be because the cards are in need of an edge cleaning, so I decided to do that. You simply pull the card, clean the fingers with a pencil eraser, make sure it free of debris, and re-insert. I have to do this to most of my units once a year or so.
This is the power supply card. Notice that there’s been a lot of repair to the unit, as evidenced by the flux-coated joints. This is not how HP would have left anything from the factory. There’s also a bit of corrosion on some of the larger joints, as evidenced by the darkened solder. This has been exposed to some dampness at some point in it’s life.
The fingers weren’t that bad, normally they exhibit marks where they’ve been placed and removed multiple times. This may have just been out a few times. Power supply is operational, so nothing to do here other than clean and replace.
This is one of the NIXIE driver cards. The fingers on this didn’t indicate any removal, and none of these cards showed any repairs.
How does this work? These are an up-counter with a wheatstone bridge. One of the bridge sides is a ramp voltage, another side is the unknown input. The ramp voltage increases and the cards count up, when the bridge becomes balanced the unit stops counting and displays the unknown input on the tubes. Of particular note is how HP decoded the output - the black “socket” for the tube contains a photoconductive plate with neon bulbs driven by the flip-flops on the card. Depending on what sequence of bulbs is lit, certain parts of the photoconductive plate are active and drive the segments of the display tube. It’s fascinating how they did that and is worth a paper of it’s own. Maybe for a future post?
Here’s the card that’s most likely the problem. The ramp generator. It had marks on the fingers indicating this had been in and out of it’s socket many times. It, for some reason, also had a lot of bug debris on it. Only this card hard that, so I wonder if this was pulled from another unit originally - usually when insects get into a device like this, their crap is all over the thing.
If you look closely, Q8 right in the middle of the card has been lifted as if someone was troubleshooting the device before I got it. So this is indeed the problem (probably!) and if I wanted to fix the device, I’d start here.
But, that’s the thing. I bought this knowing that it probably didn’t work due to the condition of the unit. It was purchased solely for parts, and parts it is. I’m not sure how much time I want to spend on this, but who knows. I may have a spare ramp card in my box ‘o junk, as I’ve purchased these units before in tear-down condition. I might wait until the snow flies and dig that box of cards out of storage and see what’s in there.
Until then, this unit is going to serve it’s function of being a parts donor for my other units.
Stay tuned, next week there’s one more show’s worth of pictures to post until late summer. The Butler Breezeshooter’s hamfest was a nice show, and I brought home stuff I didn’t need. As usual!
- 2023
- Jun
- 3
Dayton 2023: Stuff I drug home.
I made good on my promise to not drag home too much junk this year, but a few boat anchors did manage to make their way in my car. Both of them had an immediate use, but the one that was going to go in to the rack didn’t work. Not a big deal, but still…it gives me a chance to re-engineer some stuff. The rest of the items were parts for later use, whenever the need arises.
Just some random bits I picked up. An old LED display (made in the USA!) from Rat Shack, and a 1971 Allied/Radio Shack catalog. The catalog is fascinating, the prices that some of the things cost was incredible, and it’s interesting seeing some of the Shack’s staples like the Weather Cube. It’s fun to look through it and see things I wish I could still buy.
A vendor was selling older Jim-Pak parts, as well as a handful of things from other vendors. Some were $1 per, others were 2 or 4 per $1. I picked a selection of parts, as well as some of those oddball fuses old meters used for their current sections.
This is a unit that was meant to monitor the audio feeds in a studio. At it’s heart, it’s two “channels” with a center channel. Unfortunately, it didn’t work. Examination reveals a lot of white corrosion on the input board, and it looks like some water was spilled and lay on the board for a long period of time. That’s not really a big deal, I’m thinking a couple of LM386 ICs can fix this guy right up. I’m not interested in studio accuracy, I want something for my rack that I can connect to the plugboard for audio testing.
According to the vendor, this works. Well…it didn’t. Mostly. I picked it up for parts since many of these are being torn down for the displays so they can become clocks. :( The device itself had a hard life, evidenced by the replacement screws in the bottom and the considerable cosmetic damage to the unit itself. It had all of it’s feet and bail, so that’s quite nice.
An examination on the inside revealed many repairs, some boards that had left their slots, and a missing fuse. Bringing the device up on power revealed that it indeed did not work, the master clock was not present so the device wouldn’t sample. One of the tubes was also partially bad, but it had the incredibly rare polarity indicating tube, probably worth the price of the device itself.
While cleaning the card edges I found that the clock card had a transistor leg lifted, so someone was troubleshooting the device when it was put aside. As this was supposed to be a parts unit, I’m not sure how far I want to go fixing it - if at all - but it will be the subject of a future post detailing the examination.
This is one of Radio Shack’s oddball devices from the CB radio era. It’s a crystal-controlled device that listens to Channel 9, which was commonly used as the emergency channel It was designed for antenna passthrough, and has it’s own speaker. If I can find a schematic for this, I may see if I can re-tune it to Channel 19, since there’s still a little activity there.
A friend of mine said he wanted a 2-pin cable for a battery box project he made. Said he needed an extension, so I found this. It’s not going to get warm anytime soon.
This was a CB-era piece in the bins with the Jim-Pack parts. I don’t know why I got this other than it’s funny. Rip-off characters, anyone?
The slim haul wasn’t because I didn’t see things I wanted. I did. A lot of it. There were a couple of pieces that I saw that I wanted to bring home, but didn’t have a need for - a WWV receiver and some other devices among them. I figured if they were there Sunday, I’d bargain, but they weren’t. That’s me being told that I don’t need them, leave them where you found them.
(But you know very well if i see that receiver again I may pick it up because I’m being told it’s still here so you know you want it!)
Overall, I think I got some good stuff. The meter may make an interesting project, should I decide to repair it, but I think it’s just parts with a good plug-in for my other devices.
Next show is Butler, PA, and then nothing for a few month. Stay tuned for some show posts from that one, and some detail posts on a few of the devices I’ve picked up over the last year.
- 2023
- Jun
- 2
The Columbus (OH) Hamfest - August 5th 2023.
Our local Hamfest is happening Saturday, August 5th this year. This one is usually well worth the short trip and $5 admission price.
Columbus Hamfest
ALADDIN SHRINE CENTER
1801 Gateway Circle
Grove City, Ohio 43123
Saturday, August 5th 2023
8A-1P
- 2023
- May
- 30
The Breezeshooter’s Hamfest - June 4th 2023
This is generally a smaller show, but it’s one where good deals can be had - some of the “Dayton” items show up without the “Dayton” prices! I’ve always brought home a decently priced trinket or two from this one.
This year, they return to the Butler Farm Show grounds, with a single day of show on Sunday. See you there!
Breezeshooters Hamfest
Butler Farm Show
625 Evans City Road
Butler PA 16001
Sunday, June 4th 2023
8A-2P
- 2023
- May
- 24
The Dayton Hamvention 2023
We all had a good time at Dayton this year. Weather was very cooperative, with temps in the 80s and most of the rain being confined to Friday evening and early Saturday morning. (It wouldn’t be Dayton without Rain, Snow, Tornadoes, or 100F heat, now would it?)
As usual, there was a lot of good stuff to be seen and had, and I limited myself to things I thought I could immediately use - for the most part. The flea market was full, and the exhibit halls were packed as usual. So without further ado, here are my pictures of the event.
- 2023
- May
- 22
The Dayton Hamvention 2023 has come and gone.
This year, I made it two days instead of just one - perhaps next year I’ll try for all three. There was plenty of stuff to be had, and I limited myself to some parts units and some odds ‘n ends. I think the total damage this year was under $200, and that included food and drinks for myself and my fellow show-goer.
I’m in the process of cleaning up the pictures I took, and will be posting those and my haul over the next few weeks. Stay tuned!
- 2023
- May
- 16
Monster.com has become nothing but noise.
Some time ago, I changed my email address for job contacts to a domain-based email instead of a generic gmail account. This was mostly so I could track where all of the spam was coming from, since I tend to leave my profiles alone once I’ve found employment. I noticed something right away:
Almost all of the spam was coming from monster.com
During the boom in late 2021 and 2022, I would sometimes get 20-30 a day from offshore recruiters, multiple contacts from different people in the same company in regards to a job that wasn’t worth your time. This slowed somewhat to about 15-20 a week, but all of it was offshore recruiters that just matched a keyword and had no clue as to what they were recruiting for - or even that someone else from their company had contacted me.
I turned off the monster.com account, and… silence.
All of that junk, those $20/hr jobs in San Francisco, those 3 month contracts in North Dakota, those jobs that were completely mismatched to my skillset have all vanished. It’s both sad and interesting to see how one of the first big online career sites has fallen, but that’s their problem. They’re making money from all of these offshore recruiters pulling profiles. They’re not going to do a thing to disturb their golden goose even though it’s totally useless for the end user.
What’s worse, is that my state of residence uses monster as their backend for the unemployment system. Monster used to automagically connect the two, something it didn’t bother telling you about. I only found out this one day when someone told me they found my profile on ohiomeansjobs.com - I had never heard of the site but found that it was just monster.com with a red bird instead of a purple creature. Even better - if you’re unemployed, it used to not let you make changes to monster because you were a “protected jobseeker” due to the unwanted connection to the Ohio site. As soon as I left this status I made sure to disconnect the two by deleting and re-creating the monster account with a different email address, and filling the Ohio site with junk because it’s just monster, i.e. spam, with a different name. You can’t delete that one for years, even though it clearly used to say you could.
The moral of the story here is that things change, and what was once useful is no longer necessary. Monster is a zombie clone of itself, and by association, so is Ohio Means Jobs.
There’s nothing I can do about it except say “Sorry, it’s not me - it’s you. Bye.”
- 2023
- May
- 2
Random board shot - The Textolite “T”
It’s always cool (and kind of sad) to open a piece of equipment and see the GE Textolite T on the circuit board.
This was manufactured by the Coshocton, OH GE plant on South 2nd street in the 1970s. The plant opened to make laminated plastics under the trade name Textolite, and made various other things over the years including plastic parts for appliances, and raw circuit board.
It opened in 1947, and closed in 2004, a victim of declining manufacturing in the USA, and the drive for ever-increasing profits by GE. It probably would have closed at some point, as GE has sold their appliance division to Haier and there’s no reason for a Chinese company to manufacture here.
Out of all the businesses listed on that page, only Fisher remains. RIP, we hardly knew ye.
- 2023
- May
- 2
The TUSCO Amateur Radio Club 2023 Show - Junk I Took Home.
I tried to limit myself to Small Things this year, and not drag home any projects. I almost succeeded!
The meters are of particular note, one was an old, old, old unit with a telephone test jack on it. I occasionally have need to test single-line analog jacks, so I offered the guy $10 for it and he took it. The other meter, an Ohio-made Triplett, was a beast of a unit costing $200 when new in 1992. It’s loaded with functions, and has internal relays to isolate and switch inputs. Quite unusual and cool.
The other items were simply parts, unusual test equipment, or books. Not pictured are some RCA tube manuals I picked up for $5 each. You’ve seen those before.
The ZM-11/U - this is an interesting piece of equipment. It’s a fairly precise bridge for checking capacitors and inductors, and uses an eye tube as an aid to the relative quality of the device under test. It’s in pretty good shape physically, a few dents and dings and one broken bail on a clip.
Electrically, the vendor said that it worked (and it all lights up,) but that the internal 1Khz source was dead. Feed it an external precision source and it’s fine. I’m planning on digging into this device at some point, it needs a cord and some minor cleanup. I’ve already removed the line cord as it was in bad shape. When I get to it, that will be it’s own post.
Next up is Dayton on the 19th of May, but until then, enjoy the pictures!
- 2023
- May
- 2
The TUSCO Amateur Radio Club 2023 Show
This was the first time I’ve attended this show. I wasn’t sure what to expect, but it turned out to be pretty good for being such a small show. I spent about an hour and a half wandering the two halls, looking at thing and re-checking them to make sure they didn’t want to come home with me. I left several things behind but brought home several more.
This show was at the Tuscarawas County Fairgrounds, and occupied one of the commercial buildings. There was mention of a “trunkfest,” so I suspect that there may have been some outside stuff had it not been a rainy day. Overall, however, it was a good way to spend a Saturday morning. I’ll probably go next year, time permitting, since it’s so close.
