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Global Specialties PW-2120 repair

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Global Specialties PW-2120I recently picked up a Global Specialties PW-2120 Sweep/Function Generator at a local electronics shop for $30. They had it in back as broken, but didn’t have the time to repair. At the time they only mentioned that the knob was broken (it was, the whole PCB had “popped” off the back of the rotary encoder. But, some prodigious application of hot glue fixed that). The bigger issue is while the buttons and everything worked, there was zero output. Changing to any frequency, sweep, or wave shape resulted in nothing on the outputs. More interestingly, the frequency counter function worked perfectly. So that wasn’t it.

Getting out the FLIR, I was able to see that the CLC522 (variable gain amp), and the 5V regulator (7805) were both getting pretty warm. More interestingly, checking the resistance between the +5v and gnd, there was only 500ohms. That’s not right (or, at least, doesn’t seem right). Visual inspection showed something a bit worrying. U1 on the main board was missing. Now, it COULD be an add-on chip, but that seems unlikely for a chip labeled “U1”.

So, first thing’s first. I contacted GlobalSpecialties to ask for schematics or a technical manual. First response I got back was the general manual, which I had already found. So, emailed them back, and the next day received a nice zip file of all the schematics! Awesome!

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Surebonder PRO2-100

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Surebonder Pro2-100Hot Glue may be one of the most under appreciated tools of doing electronics (or any) repair, building. It’s extremely versatile, water resistant, and generally, non-conductive. Can’t figure out how to repair/insulate something? Give hot glue a go. I, for years, have used tiny hobby glue guns, and never been overly happy with their performance. Plus, with my desk wiring, I like to keep all my tools plugged into a single “hot” power bar, so that I can turn them all off with a single, separate, switch (basically, so I don’t forget to turn off the soldering iron). But, I don’t really want them all on when not in use, either. So, a glue gun with it’s own on/off switch was something I’d been wanting for a while.

Amazon reviews all seemed to point to the same gun, the Surebonder Pro2-100. But, $30 for a hot glue gun was a bit much. Then, on a video by Applied Science, he mentioned this gun as well, so I just bit the bullet and bought it. And boy, am I glad I did.

The “gun” came from Amazon in a couple days, and first off, it’s big. It’s physically larger than my desoldering gun (and, really, uses almost as much power). But, it feels great, and the full length handle gives very good control over the amount of glue dispensed. Heat up take a while, largely because the glue chamber seems to be on the large side. I say that because the gun takes almost a whole 10″ 1.2″ glue stick before it dispenses anything (so, the glue chamber is probably somewhere in the neighborhood of 18in^3) ((Half inch gluestick has a volume of .25*π^2 * 10 (24.67in^3), and figure 3/4 of that is filling the chamber)). Because of this, I really suggest getting the 10″ (or 15″ if you can get them) sticks if possible. 4″ sticks would be brutal. Especially since the gun CAN dispense a LOT of glue at a time (they rate it at 2.5lbs per hour).

The gun, though, works great. While I also purchased some black glue sticks, I actually purchased a separate gun for those so I wouldn’t have to waste glue switching between black and clear glue.

So, that all said, the glue gun is awesome. I really do like it. My only problem has been the added size has made it hard to get glue into small spaces, but there are some replacement tips you can get to alleviate this. Not sure when/if I’ll bother buying those. I also wish the on/off switch was a little bigger, and that there was an LED to show power/heating status. Small quibbles, but would be nice for a future revision.

[xrr rating=4/5]

Yaesu VX-8DR

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Yaesu_VX-8DRAs I mentioned in my Ham post, I mentioned that I purchased a Yaesu VX-8DR. This is still one of the top of the line HTs that Yaesu makes (it’s THE top of the line for their analog HTs, from what I can tell). It’s only been surpassed by the new digital line, from what I can tell, though I don’t believe either of their digital line HTs are IPX-7 certified (water resistance, etc). I basically wanted a radio that my son could get ahold of, and drop, or dunk, and not break.

So, first off, the radio is small. It’s basically as small as you could make it and still have it “fill” a “normal” hand. I have relatively normal size hands, and if it was any smaller, it would be pretty unusable. The buttons are pretty small, as people have commented on online, but the radio would get bigger if they were any bigger. There’s a lot of inputs here. If anything, the PTT button may be a bit small, but that actually prevents hitting it overly accidentally.

When I first got the radio, I didn’t have my callsign yet, so I was pretty paranoid about keying it up, but thankfully I got the callsign the next day. So that was nice.

The unit is a bit confusing to use. There is a ton of functionality there. It receives from 500khz to 999Mhz, it transmits on 4 bands (6m, 2m, 1.25M, and 70cm) ((More if you mod it)), has dual listen (can listen on two completely separate channels at once), and has AM/FM broadcast listening. So you can, in fact, listen to a local repeater, and an AM/FM broadcast as well. I found myself last night listening to a local, very active (because it was tied into the WIN system for “Insomniac”) repeater and a local FM radio station, or listening to the very local, yet dead repeater, and talking (when I could) on the more active WIN system repeater.

One tweak I would suggest Yaesu make if they continue with this design of radio… make the “volume” button configurable. The way it is with the VX-8DR is the main nob changes frequency, or channel (depending on if you’re in VFO or Memory mode), and you have to hold the Volume button to use the knob to change volume. I would like to reverse that, so volume is changed by default, and frequency is changed when holding that button.

Otherwise, the unit is great. It sounds great, feels great, and performs quite well with the standard rubber duck (I’ve just ordered a SMA to BNC adapter from Stephen Gulyas, and then a little stubby dual band antenna (Maldol MH-209) (should be good for events, or other close quarters talking, camping/hiking, or even chatting on local repeater), and a bigger whip style antenna (Diamond RH77CA). Sure, neither will do 6M, or 1.25M, but I haven’t really used them at all on this unit… maybe when I want to branch out I’ll pick up antennas for those purposes (6M on an HT generally means a big antenna, and poor results (you need more than 5W power), and 220Mhz requires something that I can’t seem to find easily (Smiley 27000?)).

All and all, I love the unit. I’m still searching for a good “pouch” for it that I can put on my bag, and unsure when I’ll buy the speaker/mic (it’s expensive). But, should be fun, and hopefully not lead to too many more purchases (at some point I’ll probably want something that’ll do true HF, but that’ll also require a license upgrade (at least General) for me for most of the HF bands).

[xrr rating=5/5]