Recent Posts

1

Power/Renewable Energy/EV's / Re: Totem Pole PFC is over-hyped?

« Last post by Faringdon on Today at 07:00:54 pm »

Sounds like you are fighting some good winning battles in getting it working.
You say you need bidi, and yes, for this reason the Totem pole PFC sounds good.

Otherwise, at 3.3kW , i wonder how much more efficient that would be when compared to a Dual interleaved PFC with UCC28070?
https://www.ti.com/product/UCC28070

...thats two PFC's each with  just 4.125A of output current.

Make the rectifier bridge synchronous and its even more efficient.
I doubt the totem pole is going to be much , if at all, more efficient than that.

2

Beginners / Oscilloscope recommendation

« Last post by CAG on Today at 06:59:52 pm »

Hey all, new user, not proficient with the search function, apologies in advance.
I'm an automotive mechanic by trade. I have recently been tasked with dealing with all the more complex electrical diag work at the shop. I have limited experience with an oscilloscope. I know only the bear bones basics. Time to get one for myself, mostly for work but I'm also interested in some hobby electronics stuff and audio signal analysis. The pico scopes are popular in my trade but the price and need for a laptop turn me off. I hoping to stay under $800 or so. Looking hard at the rigol 800 and 900 4ch scopes. Looking for opinions from anyone in a similar situation. Based on my understanding the rigol has more than enough bandwidth and voltage limits for automotive testing. The 900 peaks my interest mostly due to double the memory. Some of the tests I will be doing will not require very fast sample rate but would be helpful to be able to record a signal for a longer time. Is it possible to dial down sample rate and increase recorded signal time on the rigol? Is there a formula so I can work out how long I can record/view at a given sample rate? Does this question even make sense? Lastly should I be looking at a different scope altogether? A better option? Thanks!

3

Test Equipment / Re: Hacking the Rigol MSO5000 - Dr Mefisto Licensing Method

« Last post by BTO on Today at 06:57:52 pm »

Directions and script worked perfectly on my MSO5074.  Thanks.

It might be useful to add a reminder to use a USB stick at least 2GB in size when doing the backups.  I have a little old 64MB stick I use for updates, and that was not big enough.

Hi mate,
First, Hope your scope is going well for you .

Secondly, Want to ask you a favour about your scope, (i'm gathering some information for the sake of helping others)

Now.. You mentioned your scope was a MSO5074
However... DID YOU BUY IT STANDARD or  DID YOU HAVE OTHER OPTIONS INSTALLED FROM THE TIME OF PURCHASE ?

FYI - This is a new script file called rigol_kg2_3_00.py 
For the record, this file will not apply to you , you just keep the one that you activated with if you need to do anything.
But the original file has been modified and other users have successfully activated that couldn't before, so now i need to gather
some information to see which models are effected by this change and to find the common factor between them and this will
help me understand if i need to modify the script further.

thanks mate

4

Test Equipment / Fluke 8846A IEEE Error

« Last post by Louis_C on Today at 06:48:23 pm »

Does anyone know what could be causing this error to occur? Every time we connect this unit to IEEE, it causes this error and does not allow other devices to be detected on the IEEE chain. This screenshot is of NI IO Trace watching the unit as it goes through the INT when you open a Met Cal Runtime. 

5

Test Equipment / Re: List your test equipment "scores" here!

« Last post by yo0 on Today at 06:46:17 pm »

Keithley 195a and 2015 for about 240usd


Best regards

Pio

6

Test Equipment / Re: Siglent SDS2000X HD, 12bit, 2GSa/s high definition oscilloscope serie.

« Last post by KungFuJosh on Today at 06:45:42 pm »

You can get white velcro cable straps and cut off the excess. That'll hold better than the little rings that like to break off.

7

Test Equipment / Re: Agilent 16801A Manuals

« Last post by gslick on Today at 06:44:52 pm »

I'd expect the 16800 series acquisition boards to be fairly similar to the 16750 series of plug-in blades for the 16700 and 16900 series.

The 16803A, 16806A, and 16823A logic acquisition boards are essentially identical to 16910A 102 channel logic acquisition modules.

The 16802A, 16804A, and 16822A logic acquisition boards are essentially identical to 16911A 68 channel logic acquisition modules.

The 16801A and 16821A logic acquisition boards are essentially identical to 16912A 34 channel logic acquisition modules, but 16912A modules never existed as standalone products.

The 16821A, 16822A, and 16823A pattern generators boards are essentially identical to 16720A pattern generator modules.

As far as I know there must be some different values in the EEPROMs of these modules that lock them to use in 16800 series analyzers and normally prevent their use in 16900 series analyzers.

Anyway, if any self tests fail on the logic acquisition boards there probably isn't a lot that can be done to try to repair them, other than looking for corroded PCB traces that sometimes happens due to the corrosive adhesive issue on the skid runners on the bottom of the logic acquisition boards.

8

Buy/Sell/Wanted / FS: Tektronix SC502 98% working

« Last post by BlownUpCapacitor on Today at 06:44:44 pm »

I have an SC502 that I want to sell. I see an SC503 going for $500 on ebay, but as we all know, ebay really likes to inflate prices.

I don't see many of these SC502s being sold so I'm not sure of a good price to sell it at while I don't sell it for too cheap, or have the price too high so some poor fellow spends too much money (true story).

This SC502 works perfectly fine with one issue, the trigger source select switches offset the trace? This only happens to channel 2. Channel 2 is centered when sourcing the trigger from CH2. But when I switch it to CH1, it offsets the trace by about 1.5 divisions. I don't find this much of a problem though as I can just re-position the trace. If you fiddle around with the switch a little bit you can get CH2 to center again, but it's a difficult to hit sweet spot.

I'm sure this is just some bad contacts, but no matter how much deoxit I spray into it, it doesn't help.

Well, that's the only issue! Everything else works fine. Mag registration was calibrated, and the scope seems to be in decent cal. Could use some more work, but I'm selling this anyways and don't want to re calibrate it as I would have to disassemble my TM504 unit.

This unit was modded by me to add a function so that a DC504 frequency counter can measure the frequency being inputed into the scope. This is done by soldering a wire and siphoning off the trigger input signal and connecting it to the DC504 internal input through the TM500 power unit. You will have to desolder the 51 ohm terminating resistor though in the DC504.

The SC502 also had a recent repair: https://www.eevblog.com/forum/repair/tektronix-sc502-alt-and-chop-mode-fault/

I fixed it my replacing Q350 and it works perfectly now (apart from the trig source trace offset).

I'm thinking $300?? But I really don't have that much of an idea... 

I have fallen into the tek scope addiction and now have 7 tektronix oscilloscopes. I need to thin a herd a bit... Then use the new money to buy 3 more tek scopes 

If you are picking this unit up locally, you are free to test it all you want before finalizing the purchase. I have an FG501 and PG501 unit you can use to test it.

I am selling only the scope. No TM500 power unit nor any cables.

Located in Carmichael, California, USA.

9

Test Equipment / Re: Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

« Last post by mawyatt on Today at 06:44:25 pm »

Here's my SDM3065X set at 100PLC connected to an AD584 ref.

Thanks, if you can let it run for a day or so and see if you spot any of what we've shown.

Best,

10

Test Equipment / Re: Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

« Last post by mawyatt on Today at 06:42:56 pm »

Popcorn may not be visible when measuring resistances, because the same voltage source is the reference voltage for the ADC and the reference voltage of the current source.

Good catch!!! Caught me when I wasn't thinking

Best,