What did you buy today? Post your latest purchase!

[tkuhmone]

Considering of buying this as my first scope, currently it is on lending. Tested already, it works ok :-)

[Smokey]

I picked up a "mystery" Amrel electronic load.  It's missing the part number name plate, and the LCD and surround don't match any of the models I could find in the Amrel data sheets (No CC, CV, etc markings around the LCD like most models). 
Anyone recognize what model this is?

[artag]

Two more HP power supplies. Oops.

[mmagin]

I needed a 3456A because my 3457A doesn't have beautiful 7-segment LED display.    Also, I think this one may never have been calibrated since new, but damn it's super-clean.  And I got the full manual binder with it.  Quick peek under the shield attached (though the digital board is pretty clean too -- this is one from after the ditched the fan.)

Maybe I should sell one of my 5.5 digit meters now

[bitseeker]

I needed a 3456A because my 3457A doesn't have beautiful 7-segment LED display.   

That's a beauty. Plus, how often do you get a device with sequential digits in the model number?

[djos]

I needed a 3456A because my 3457A doesn't have beautiful 7-segment LED display.    Also, I think this one may never have been calibrated since new, but damn it's super-clean.  And I got the full manual binder with it.  Quick peek under the shield attached (though the digital board is pretty clean too -- this is one from after the ditched the fan.)

Maybe I should sell one of my 5.5 digit meters now

Nice, what on earth are the dip packages that are bolted to the mainboard?

[mmagin]

Those are custom HP hybrid circuits, likely a combination of precision resistors and FET switches.  If you look at the frontend circuitry in the service manual you can get some idea about what they're doing.

[djos]

Those are custom HP hybrid circuits, likely a combination of precision resistors and FET switches.  If you look at the frontend circuitry in the service manual you can get some idea about what they're doing.

Cheers, amazing that they are bolted down, must have had thermal expansion issues to go to such extremes.

[Cubdriver]

That 3456 looks to be in beautiful shape!  It's interesting how they have that clump of TO-92 transistors that are on Teflon islands for isolation, and they're connected to several carbon composition resistors, some of which on mine at least are 10% tolerance.  LOL - I can't recall seeing 10% carbon comps in ages.

I'm not certain because the few pics I took for someone a year or so ago are from above and don't show it clearly, but I believe that the custom hybrids are little daughter cards, as at least one of them appears to have flying leads radiating from beneath it.  I think they're mounted on standoffs and the standoffs rather than any pins they might have are providing the mechanical mount.

-Pat

Edit to add - yours has the same 10% CCs at the top center of the board photo.

[mmagin]

Yeah, I can only assume those are used for the pulse-withstanding capability and not any kind of precision

[GreyWoolfe]

Actually, not today but over the last couple of weeks.  500 ft of 14 ga stranded THHN wire, 1,000 ft of black paracord, 100ft of 450 ladder line and a bunch of 3 ft heavy duty bungee cords in preparation to making and putting up a full wave 80 Meter loop antenna.  A club member gave me a good sized piece of 1/2" acrylic and another donated the use of his bandsaw and drill press to make the center isolator.  It will be nice to get back on the HF bands again.  The radio looks so sad 

[lmester]

I got a GW GUC-2020 universal counter a few days ago. $25 including shipping! Fully functional. good condition. Plastic case a little yellowed. I compared it against my GPSDO. After a long warmup, the calibration was surprisingly good. I didn't bother fiddling with the the oscillator trim cap.

If you don't have a frequency counter, you can't go wrong buying one of these! Last time I checked, there were more still available on Ebay for $25. Another big pile will be coming soon. Three more ITT schools will be auctioned off in february.

Do I really need this instrument? No! I have a HP5335A counter. I need this just as much as I need another multimeter  When I saw the $25 price I couldn't resist! I may just wait until the ITT equipment blast goes away. Re-sell it for a small profit.

Details:
This is NOT a precision counter. It doesn't have an external timebase input. It has only a crystal with no temperature compensation. Even worse, it has a really bad PCB layout. See the pics. The crystal is right next to a voltage regulator heat sink. Probably why it took about 30 minutes for it to stabilize and show a good 10 MHz reading. A hot heat sink right next to the crystal is not going to help the warmup time.

Finally, It's not the best frequency counter. If you don't need extremely precise frequency measurements it'll be a good choice. What other instrument can you buy for 25$ Maybe a crappy Chinese multimeter

[richnormand]

Got it yesterday.
Prompted by this post:
https://www.eevblog.com/forum/testgear/bunch-of-keysight-u1252b-meters-around/

Seems to work well and rugged too.

[firehopper]

I got a camera drone for myself

[Vgkid]

And a Quadtech Resistor Replacement Switch with 10- Precision Resistor Company 1 Meg .008% resistors.
10 dollars !

Where did you manage to score those, nice.

[MadTux]

Those are custom HP hybrid circuits, likely a combination of precision resistors and FET switches.  If you look at the frontend circuitry in the service manual you can get some idea about what they're doing.

There only precision (absolute, in current source for resistance measurement and relative to each other in voltage divider) resistors in these hybrids. No active parts in there, which makes it very service friendly :-)
BTW, if you press 6, store, N digits disp, you get another digit more. ;-)

[gbyleveldt]

Two GW Instek 8251 DMMs, Agilent 1252b (I was tempted to grab 2 as well) and 6 sets of probe master leads (to go with all the other DMMs I have). The US reshipper I use came in real handy for combining all these items so shipping was a fraction of what it would've been. All these come from recommendations here, so I guess I need to log in a lot less frequently 

[Conrad Hoffman]

Got an oven stabilized oscillator for my frequency counter, but haven't had time to install it yet.

[mmagin]

Those are custom HP hybrid circuits, likely a combination of precision resistors and FET switches.  If you look at the frontend circuitry in the service manual you can get some idea about what they're doing.

There only precision (absolute, in current source for resistance measurement and relative to each other in voltage divider) resistors in these hybrids. No active parts in there, which makes it very service friendly :-)
BTW, if you press 6, store, N digits disp, you get another digit more. ;-)

Interesting.  I hadn't studied the 3456A schematics as much as the 3457A sschematics yet.  I did figure out the digits displayed and NPLC early on.  The interface is very different from the 3457A that I have.

[artag]

Collected some recent purchases - a lovely variac (cressal torovolt) and two more HP6632Bs. I don't know why I wanted more 6632s. I just did. I've been happily fixing their minor faults today when I should have been doing my tax return.

[djos]

Rescued and old Roomba 560 from gumtree yesterday, lady said it just needed new batteries. Lol.

As I suspected it needed a full teardown and service plus a new battery, filters and brushes.

It had several dozen dust bunny colonies living inside and hair wrapped around everything that moved! I doubt it has ever been taken apart and cleaned before.

Oh and because it's an American unit I got a free 65w step-down transformer which is not half bad quality. I won't need it for the Roomba for long tho as these units only need the plug, mov, 47uF cap and time delay fuse replaced to run on 240v - I'll do the mod on the weekend.

The main reason for buying it is to clean my workshop / garage floor - I was using my spare Neato xv11, but it's far too good a bot to use in the garage. That and it's lidar keeps getting filthy with dust and needing a clean.



And happily charging up under the Workbench after some TLC.

[nfmax]

Rescued and old Roomba 560 from gumtree yesterday, lady said it just needed new batteries. Lol.

Did the main brush motor need any attention? I have a 560 where the brushes no longer turn, and it seems from Googling about these motors have a tendency to fail. I'm uncertain how much time to put into trying to fix it, so any hands on experience is welcome!

[djos]

Rescued and old Roomba 560 from gumtree yesterday, lady said it just needed new batteries. Lol.

Did the main brush motor need any attention? I have a 560 where the brushes no longer turn, and it seems from Googling about these motors have a tendency to fail. I'm uncertain how much time to put into trying to fix it, so any hands on experience is welcome!

Yes it was full of dust bunnies too, after cleaning out the motor I put some Kapton tape over the vents.

If your motor isn't turning I'd take apart the CHM gearbox as it's prolly full of garbage and all bound up, the motor itself will prolly be fine after a service. The biggest flaw in the Roomba 5xx series is the lack of sealed bearing in the CHM which lets all manner of garbage in. Once you've cleaned it, re-lube it with clear or white lithium grease.

If your CHM is completely stuffed, you can buy the motor module for about $39 USD or the entire CHM for around $59 USD from eBay etc.

[nfmax]

Rescued and old Roomba 560 from gumtree yesterday, lady said it just needed new batteries. Lol.

Did the main brush motor need any attention? I have a 560 where the brushes no longer turn, and it seems from Googling about these motors have a tendency to fail. I'm uncertain how much time to put into trying to fix it, so any hands on experience is welcome!

Yes it was full of dust bunnies too, after cleaning out the motor I put some Kapton tape over the vents.

If your motor isn't turning I'd take apart the CHM gearbox as it's prolly full of garbage and all bound up, the motor itself will prolly be fine after a service. The biggest flaw in the Roomba 5xx series is the lack of sealed bearing in the CHM which lets all manner of garbage in. Once you've cleaned it, re-lube it with clear or white lithium grease.

If your CHM is completely stuffed, you can buy the motor module for about $39 USD or the entire CHM for around $59 USD from eBay etc.

My Roomba now goes into the big pile of things waiting to be repaired...
Thanks!

[nctnico]

Today I bought this: a 24W 30x30cm square LED lamp to play with.

My (slightly crazy) idea is to fit the entire bathroom ceiling with these (without the supplied converter) and control (dim) them individually to create a lighting and ceiling solution for the bath room. The idea is still in it's brewing stage though and I have not decided yet to go through with it or not.