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Introducing my new YouTube series. How not to package stuff….
This is the HP OCXO. Haven’t opened it yet as I’m too busy
I hate most yootoob vids because talking heads are a waste of my remaining life. Irritatingly that avoids both of those traps. I'm still not going to become the 7th subscriber, though
I aim for information density where possible also as I value the amount of effort I don’t have to put in
I will actually say that took 4 takes to get right because the 8 year old holding the camera either talked over it at some point, put her finger in front of the lens or forgot to actually record it.
She has been fired
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I will actually say that took 4 takes to get right because the 8 year old holding the camera either talked over it at some point, put her finger in front of the lens or forgot to actually record it.
She has been fired
Tee hee.
With a hot air gun presumably
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So having fixed the GPS receiver in my hamfest buy Rapco 1804 GPSDO I plugged it in to power and antenna and let it run. Unfortunately it never got within 90Hz of 10MHz.
Plugging a PC in showed the GPS was getting a full set of satellites with good signal strength. The unit uses an HCD 66 OCXO with an SC cut crystal. Being this far off normally means an oven fault, but the unit felt warm. A test point next to the OCXO looked like (and turned out to be) the tuning voltage, This was stuck at 4.2V. So pulled the OCXO off and stuck it on the bench. Current from cold was about 15mA. So clearly no heater operating. The warmth in situ must have been conducted from other parts.
The unit is soldered into a can. There are two or three ways to tackle this type of construction. Heat it up to melting point and pull it apart. This can damage internal components and almost always will damage labels. Take a dremel or similar miniature rotary tool to cut the can or the solder. This can work if the solder is accessible and you don’t remove too much can. Finally, and my choice for this one, is to peel the metal back at the joint breaking the solder. The base overlapped the can on this unit making it easy with a pair of side cutters.
With it open it was clear that the heater and power control element is a TIP121 transistor. The collector to 12V and emitter to gnd via a 4R7 and 3R3 (1.9R) in parallel Temperature sensor is a thermistor of about 10K. There is a 8pin SOIC that appears to be a LM358 clone. I pulled the TIP121 as low impedance circuitry around it prevented in-circuit checks. It tested fine but the heatsink compound on it was dried out and obviously had neve had good coverage in the middle of the transistor were it is most needed. This means the transistor and PCB nearit was probably running hot. Date code is 1995.With the power device out I could check some other components and trace out the power circuit. Base drive was from the 358 with a SOT wired between the TIP121 base, emitter R and ground in a classic current limiter circuit.
But, the TIP121 Base connection read about 18R to ground. There were a couple of chip capacitors across the base emitter junctions of both transistors so could be these or the SOT. De-soldered the SOT and no change. It was the larger or the two chip capacitors. When pulled it read 10R (had extra cooking). No markings of course. So I pulled a similar looking one of a scrap board. It was 10nF which seemed reasonable so I stuck it in. Some temporary foam insulation and powered it up. It took about 320mA (about right for the 1.9R and 0.6VBE) and frequency started pulling rapidly. All seemed OK after a soak test including VFC so I cut some new insulation, bent the edge of the base back and re-soldered it. BTW all soldering was done with a Weller TCP and 1/4" chisel bit
Stuck it back in the unit and all works.
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Nice job. Enjoyed reading that one
Always wondered if anyone sells a small can opener for stuff like that. -
Introducing my new YouTube series. How not to package stuff….
If it wasn't fecked before, it is now after that shake down
This is the HP OCXO. Haven’t opened it yet as I’m too busy
Seriously they could have found a bigger box to put such a small thing in, oh no, they don't make tea chests anymore do they
And your second subscriber
meh. I'll just bookmark your page until something forces me to log in.
I don't feed Gurrgle any more often than I absolutely have to. 
Nice view from Beacon Hill, BTW... makes me homesick for the ol' homestead in East BumbleFuck, NY.
mnem
*toddles off to lick a unicorn*
Just feed "ht<-remove me->tps://www.youtube.com/feeds/videos.xml?channel_id=UCPEZvrC2nfJG8w_bf23sBSQ" into your favourite RSS reader and you don't have to go anywhere near YouTube's subscription system. For channels other than BD's, just change the channel_id. -
I will actually say that took 4 takes to get right because the 8 year old holding the camera either talked over it at some point, put her finger in front of the lens or forgot to actually record it.
Oh dear what could possibly go wrong ?
She has been fired
Training up an 8yr old to use YT.......I can see vids of pop posted at the most inconvenient times. -
Yeah, replace her with a tripod, cheaper in the long run and less hassle.Introducing my new YouTube series. How not to package stuff….
This is the HP OCXO. Haven’t opened it yet as I’m too busy
I hate most yootoob vids because talking heads are a waste of my remaining life. Irritatingly that avoids both of those traps. I'm still not going to become the 7th subscriber, though
I aim for information density where possible also as I value the amount of effort I don’t have to put in
I will actually say that took 4 takes to get right because the 8 year old holding the camera either talked over it at some point, put her finger in front of the lens or forgot to actually record it.
She has been fired -
*ring-ring*I hate most yootoob vids because talking heads are a waste of my remaining life. Irritatingly that avoids both of those traps. I'm still not going to become the 7th subscriber, though
I aim for information density where possible also as I value the amount of effort I don’t have to put in
I will actually say that took 4 takes to get right because the 8 year old holding the camera either talked over it at some point, put her finger in front of the lens or forgot to actually record it.
She has been fired
"Ummm.... yes. This is mnem from HR; we understand you've sacked your camera-err-person. Just to let you know, we have a few questions regarding the ahem... incident, given that she is a member of a minor-ity, and we have very strict job-security requirements in effect due to BREXIT, etc... and we can't just go firing people willy-nilly..."
"First, has she been given anything other than a satisfactory performance evaluation in the last 6 months?"
"errr..."
"I'll take that as a no. Has she been given government-approved training on the use and safe carrying of the camera in question?"
"There's government training for a Kodak Clicky...?"
"Oh, yes there is, sir... and she is required to have it. Next... aboot the finger placement problem; has she been offered fitment for custom harness by a qualified camera-fitment professional? Also, has she been offered a cookie if she will keep quiet while shooting? As you know, there are strict guidelines when working with minor-ities; we have to work around her cultural identity, and Oreos are part of that heritage."
"She is not a minority... she is a minor..."
"A what...?!? Oh dear... was this known at the time she was hired? We may have a code 4242 on our hands... especially if daycare services weren't offered in a timely manner in the event of naptime..."
*rustling of papers and thumping of large rubber stamp in the background*
"You just wait on the line; we'll have an operative there in..." *screeeching of tires stops just short of the door* "Oh look; she's there now...."
mnem
This stream of consciousness brought to you by the number blue, and the color Wednesday.
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Hahaha that’s about it. Don’t get me started on HR. I’m currently pissed with them. So you’re not going to pay me for overtime on week days but will at weekends? Oh yes so I can take time in lieu ? Oh brilliant in that case I’m signing out for the afternoon as time in lieu? Oh I can’t do that either?
So I just rejected all booked meetings for me and am concentrating on doing something unimportant with thorough levels of overkill and professionalism instead as was applied to me
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So having fixed the GPS receiver in my hamfest buy Rapco 1804 GPSDO I plugged it in to power and antenna and let it run. Unfortunately it never got within 90Hz of 10MHz.
Plugging a PC in showed the GPS was getting a full set of satellites with good signal strength. The unit uses an HCD 66 OCXO with an SC cut crystal.(SNIP)
Stuck it back in the unit and all works.
Nicely MacGyverfied!
I think you need one of these:
mnem
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Bargain for you guys in the US: https://www.ebay.co.uk/itm/Agilent-E3648A-DC-Power-Supply-Parts-Unit-/184995561039?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0
Unregulated output on channel one. I’d buy it if it wasn’t $100 for shipping and customs!
Schematics and service manual http://ridl.cfd.rit.edu/products/manuals/Agilent/power%20supplies/E3646AE2.pdf -
Sadly, shipping/duty brings the price up to ~US$200 to me.
Nice job. Enjoyed reading that one
Always wondered if anyone sells a small can opener for stuff like that.
I picked up one of these NIB at the Thrift a couple years ago... it works well, aside from the niggling annoyance of the little strip of label paper it makes that has to be collected and thrown away; the fact you can start it, go to the bathroom and come back to a open can more than makes up for that.
As you can see, it cuts the side of the can... I've often wondered idly what other kinds of can the mechanism might also be adapted to open...
mnem -
OK back onto the Thurlby Thandar SM630 scopemeter which was supposed to have had a backlit display but never worked, and after a chat with bd139 who told me that I should expect to see around 120Vac on the EL panel and then subsequently checking said voltage it was 70Vac. With the total absence of any available service manual for SM630, I dived in to pull the driver out of circuit and investigate.
Using my desoldering gun, the Duratool, lifted the components and checked them, and they checked OK, so I pulled the transformer out and looked for shorted windings and in the process of lifting the tape of the windings, managed to break the winding. That meant I was resigning myself to having it working just like a SM620, no backlit screen, but godbd139 came through with a golden nougat and said that small EL drivers could be had from the bay of evil for not a lot of cash. Great, bd saves the day once again, so off I go and selected 5V USB driver and ordered it, only to have the order cancelled a few days later as the seller could not find it Found another seller and ordered again. It arrived today, and tonight I set about fitting in the scopemaster, using a couple of connecting posts made from resistor legs, I connected the common ground and supply to these posts and insulated with heat shrink tubing and wired the live feed to the EL panel directly into the PCB and switched ON, it only works, Yah I now have myself a working portable dual trace scope for a fraction of the Fluke 99B that Stewarts of Reading were hoping to sell me for £125, plus delivery and VAT, and it does a lot more besides, and it can be powered via a wall wart or internal batteries.
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Wireless keyboards
Ok so it was warning me of critical battery level for the last month.....not unexpected as the Scotsman in me uses AA cells that no longer work in my radio muffs and I get a few months additional use from these dead cells.
But halfway through a email the keyboard chucks it in .....all fair enough as I've extracted the very last pW from the little buggers and a hunt around fails to find anymore AA's that have been carefully saved and put aside so to have their last pW extracted too.
So despite some reluctance a brand new pair were placed in the keyboard (extravagant I know !) and that's when the fun started !
Would the little mongrel keyboard re-pair with its receiver....no furking way !
Wired would work fine but I like to type with it on my lap and if swiveling 90o to the workbench wired keyboard cables are too short.
So batteries checked again for correct polarity...check.
Try another USB port....check.
Reboot PC.....check.
Get best reading glasses and recheck proper pairing procedure...check.
Hmmmmm
Pull new batteries and reinsert them............BINGO !
Still and just hope it's not gunna be one of them days....oh wait, in NZ it's Friday the 13th ! 
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@Specmaster: that looks like a nice little instrument that. Great for general purpose debugging stuff. What does the DMM side of it look like?
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Introducing my new YouTube series. How not to package stuff….
This is the HP OCXO. Haven’t opened it yet as I’m too busy
I hate most yootoob vids because talking heads are a waste of my remaining life. Irritatingly that avoids both of those traps. I'm still not going to become the 7th subscriber, though
But I do. Yay, last prime number before 10! (And I am allowed now to eat 9)
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...Oh, and y'all would be proud of me... I didn't go all rabid dwagon nor nuttin'; just simple & sweet as sugar in my request:
OK, who are you and what have you done with our Dwagon?
"This part was listed as "used" from a working laptop. It is "damaged". There is a very prominent gouge in the digitizer film right in the middle of the screen. I cannot use this part, and quite frankly it never should have been put up for sale."
mnem
Just chalk it up to the bigger fish to fry effect of moving dwagons.
mnem
Oi... more blurry pictures accompanied by an argumentative stance and declaration that the part was sent out in "perfect" condition.
"Sorry J*****... "perfect" is not what arrived; your pictures simply are too fuzzy to show any such detail. This is damage to the film on the inside of the screen. It is the digitizer itself, not the glass which is damaged.
No, this is not some detritus on the screen either. It is damaged. If you like I can take some more pics with a microscope; I just didn't have time this morning when I was checking this out.
Thank you for your time,
mnem "
mnem
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Two major changes since my return:
1) This thread is sticky
2) This thread is moving so so fast, avalanche effect.
Perfect summary, Zucca. And I've almost been cured of my TEA FOMO...almost.To be fair I think this thread has evolved into its own forum at this point
Yes, a forum with no categories. It's a non-stop flume ride.
The monster grows...
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quick update: received new hematology data today. Seems that the rapid weight loss coupled with exercise and extremely low carb had a positive effect on my prediabetes ...
blood insuline levels more than halved to about 7.7 down from 16, HBA1C constant at 5.5, blood sugar levels within normal parameters (< 100). Cardiologist said that I am on the right track and defeating the insuline insensitivity, thus preventing a type 2 diabetes.
Some good news for a change.
That's great news, Saskia. I've been on a similar program. Reducing carbs has been the hardest part. Two out of three ain't bad, right?
Well, at least it's directionally correct.
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5381A update.
...
For the sake of people landing on this via Google one day, the new blue resistors are Royal Ohm 220R 1% 0.25W and Displays are Kingbright SA03-11EWA which are drop in replacements.
If you do futz with these, make sure you run with the lid on as there's live mains in easy accidental brushing distance of the top of the chassis.
That turned out great, bd!QuoteI really need to buy myself a DSLR again...
Made a template for ya to save so much typing:
"I really need to buy myself a(n) _______________ again..." -- bd139
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Meanwhile on qwertee:
Types of TEA:
Ok, seems that this one is especially for the TEA-Dwagon.
Hmmm...surely this could be adapted to our types of TEA. -
If there's a t-shirt showing the "TEA" being thrown into the harbor I'd wear it.
TEA being thrown into a harbor = -
Maybe I should have a t-shirt printed with this on it? What do you think?
Yes! Perfect.
OK, so if we were to make some TEA-shirts, where's the place to do it? There are so many on-demand vendors, but which ones are actually good? -
The Fluke 8300A arrived yesterday, packaged pretty well to my pleasant surprise. It powered up without a hitch and has been sitting connected to a resistance standard overnight. It's within 2 ohms of the standard it's currently connected to, so I'd say the resistance functions, at least, seem to be operational. I'll connect it to the DC calibrator later to see how it fares there, and perhaps try to get the AC one operational, too. More photos to follow once I take a good series with the DSLR rather than the iPhone.
Glad it arrived safely! I messaged the seller about your buying it, just to see what'd happen. They said, "Wow, what a small world! Maybe your friend will give you visitation rights."
Is the front panel plate loose on the right side? It looked a bit like it in the listing. -
Introducing my new YouTube series. How not to package stuff….
This is the HP OCXO. Haven’t opened it yet as I’m too busy
Subscribed ...
Yay my first subscriber
Subscribed as well.QuoteI’m going to do some proper content at some point. Probably forward engineering and repair stuff if I get the time.
I made a TEA channel a bit ago to also "do some proper content at some point."
Oh, and the TEA channel subscribed to you, too.
QuoteOCXO box works nicely. Surprisingly the unknown uncalibrated 5381A is only 0.4Hz off and rock solid. Now I need a GPSDO to check the OXCO against
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I’m wondering if I bother with buying that 5334B or just use this and keep the OCXO box as a transfer standard until I find someone who can check it properly. It’s probably enough for my trivial requirements like this now.
Edit: I’m being an idiot. Of course I need the 5334B
What about a 5334A to go with it?