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1
Power/Renewable Energy/EV's / Re: Solar Upgrade AGAIN
« Last post by EEVblog on Today at 07:32:06 am »
Ok, so the solar upgrade IS happening in the next few weeks. Indeed it MUST happen.
Those in the supporters section know why.

Complete re-install of all panels.

I have two options, both of them involve buying at least 4 new panels + Enphase IQ8AC microinveretrs.

1) Go completely Enphase and replace all old 250W panels with new ones.
Costs about $7135 and gives me 8.88kW peak
Requires a 3rd Enphase IQ relay circuit which I don't have room in the box for, so small extra charge to add that.

2) Continue Enphase/String mix and reuse old 250W panels on the 3kW Sunnyboy inverter. Plus minor update to Enphase (4 extra panels)
Costs about $2760 and gives me 8.6kW peak

I could go zero extra cost and just replace everything I already have (14 enphase + 12 string), but I can fit 2 rows of 9 panels on the west side roof, so makes sense to expand the 14 panels I already have to 18 just to fill that side of the roof.

I could fit a few more on the east side roof, and if so I'd buy some more Enphase as I have some extra current capacity on the existing IQ relays.


So it seems like a no-brainer to reuse the old 12 x 250W panel and Sunnyboy inverter?
In either case I haven't included the install cost which is roughly the same for either solution.
2
Microcontrollers / Re: PCB design question (crystal end ATmega)
« Last post by pcprogrammer on Today at 07:26:06 am »
You can clean it up by putting the two capacitors on the same y location and ground them on opposite sides. Then the trace from the crystal won't pass underneath the capacitor and takes less space. I also don't think you need to block out the ground plane underneath the crystal.

Another issue with SMD and a top ground plane might be with reflow based soldering where the heat dissipation for the pads of a component differs. Tombstone effect may happen. Not a problem when hand soldering.
3
Beginners / Tektronix TLA 614 CMOS or NVRAM location
« Last post by gearheadgeek on Today at 07:23:13 am »
Hello people I will cut straight to the point. I acquired and Tek TLA 614 with a broken screen after determine it can be fixed I got a screen but what I wanted to do is the same thing I did to my TLA 704 is upgrade to a external CMOS battery and a SSD drive and the 704 went off without a hitch no problem but the 614 well I searched the internet for a battery location but could not find one but I did find out about the NVRAM chip. I seen where people replace those but that might be above me. I'm just a old tinker who like to take things apart to see how they work or fix them and give them away. do you think you guys could help me on this it would be much appreciated
             thanks in advance
4
OK, down the rathole again with a CSA8000b...

4 to 5 yrs ago, I bought a CSA8000B for $150.  The person was local, college student thought it was a scope, even delivered it. It powered on but had the Dallas eeprom (if that's the right term) issue so it didn't boot.  The instructions on eevblog are good and I was able to bring it up but you need the dallas eeproms to hold the boot instructions or its a hassle getting it to run.  So I bought the dallas modules for both the PC and PPC boards, carefully soldered them on, had to go back and touch them up, etc.  Not a lot of fun as one is up next to a card connector and yes, I had some melted plastic by the time it was done.  I had programmed the eeproms and the unit booted correctly. I have a 20Ghz electrical module and that came up.  But when I measured the calibrator, I remember the voltage was low by a factor of 10 maybe. So after playing around with settings I powered down, reseated the cards and of course, my brand new eeprom from asia hadn't held the config.  There isn't much in there, just a couple instructions on where to find the PPC boot code!  But do you think it could keep it just once!! Nope.

And this really po'ed me!  While typing this the guy who agreed to sell it to me for the asking price just said he had a higher offer, $50 more.  That's a little lame, don't you think?  Told him to keep it.  This is a company too, not just a person on the web.  I mean is that any way to do business?  :-//

Jerry

What NVRAM's did it use? Some can be replaced with FRAM, other NVRAM's are still available new from Digikey/Mouser.
I have a couple new chips at home (date codes of late last year) that I bought as spares when I was replacing them in some TDS500/600 scopes. You can't buy the timekeeper ones new but some of the standard ones you can.

There's also a guy on ebay (kellyjo IIRC?) that makes reproductions that work great, and have accessible batteries for easy future replacement.
I have them in my TDS784D and TDS794D and they work great.
5
If you accept that energy is a point like object called photon, your definition of constant will fail instantly.
If not then you have few single photon experiments to explain.
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You need to keep up Martin72, things have changed.
That said, applying the original update following a firmware update is very straightforward; not at all a bind and keeps the MSO5000 fully featured.

Back on topic - Martin, thanks for the additional videos man, will work through them.
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General Technical Chat / Re: Baltimore Francis Scott Key Bridge collapse
« Last post by mfro on Today at 07:17:05 am »
Stick a $10000 tag on each container and they will be gone by tomorrow.
8
Test Equipment / Re: Test Equipment Anonymous (TEA) group therapy thread
« Last post by m k on Today at 07:16:10 am »
Dallas chip is not ROM, it's RAM with battery, maybe also RTC.
It's completely internal when Vcc goes down, so you can't test its internal battery without opening its case.
If settings are not permanent you can guess that battery is empty.
If the chip includes an RTC and has low battery the time was usually first to stop functioning.

Normally PC has a setup where default values can be selected by a single button.
Old PCs had it differently and very old PCs had old style HD settings.
Back in the day empty batteries was a regular thing, so how to boot was also noted somewhere.
I had a habit to ink HD number on the back of the case.
If current time and power off was needed inputting time after every power on was irritating very fast.

Some PCs had also an external battery connector.
I remember that it was regularly changed to in use, but can't remember what the actual chip was.

Would like to strip these boards, but it just takes to long

Unbent legs and you have a change.

I tried unregulated hot air fun, it wasn't very nice.
Chips didn't fall out, I had to knock the board.
Finally many were off, but many were also lumped together.

Pros had a small wave pot.
There you had rollers inside a tin and moveable walls.
Rollers were pushing the wave up and over the walls.
Height is critical, so some sort of a jig is also needed.

Don't know how regular hot air thing works.
The body has quite a bit of mass.
9
Metrology / Re: LM399 based 10 V reference
« Last post by dietert1 on Today at 07:02:00 am »
R2 and R3 are exchanged.
R4 should be about 3K instead of 10K.
U3 needs a heatsink and is mounted outside the oven. A higher supply voltage is preferred, like 15 or 18 V. 15 Vac will give you about 22 V from the rectifier. Depends on the heater power.
U4 should be mounted close to the PTC.
10 V tuning is better with fixed resistors (as far as possible).
Concerning the output buffer it depends on what will be the application of this reference.

Regards, Dieter
10
Test Equipment / Re: Tektronix 2445B calibration
« Last post by calibrationfixture on Today at 07:01:02 am »
Hi,

Copying ALL Data from a good working 24XXB Scope into a fresh Dallas Chip should work with no problems. Done that before with a 2465BDM, which Dallas Chip was corrupt. I suspect a HW Issue, Most likely the Trigger-Hybrid as was the case with a serviced 2466BHD. Gives also ?'s between Scale Factors.

Success,

Calibrationfixture

 
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