Oscilloscope YOKOGAWA LD1640

[GGMM]

Hello,
For now I can not troubleshoot my DSO because my station is down (I wait for the components), despite everything I wonder about this post and especially towards the end where a script is written to test the memory (?)
see here:

https://www.eevblog.com/forum/repair/tds-754d-diagnostic-test-acquisition-fail/

I really wonder how it works and more, the result of the defectful chip is displayed (Very strong!!)
I don’t know if this indication comes from the app itself from the DSO.
So I wonder if we can do the same thing on the LD1640(?)
My LD1640 has mainly a serial port.
I found on the Yokogawa site 2 programs to emulate the serial port.
See Doc.
Otherwise I have no additional information. I want to avoid any additional damage (Ex: Overwrite the internal program).
It sounds a little complicated, but just in case

cdt

[GGMM]

Hello,
I started changing at least 2 of 4 ELPIDA memories 45128163G5 A75 -9JF
We find the datasheet, but I want the internal schematic if possible. Indeed by comparing to the multimeter the impedance seems different on some outputs DQ. Ex the DQ2 or DQ3 compared to the DQ1/ mass.
 The memory acquisition part of channels 3 and 4 that work have the same impedance  on DQ1 to DQ15.  Maybe there are open collectors or other?
thank's for your help.
I continu my research..I will also look at VCC and VSS because there are several on these chips

cdt

[GGMM]

Hello,

I started changing at least two of the four memories.
And no luck, the result is disappointing.
I may have done something wrong, but actually give an indication.
So I still have an error on the acquisition memory for channels 1-2, but now an error on the SNAP memory.
This would prove that I may be on the wrong track and that this memory would only be used for catching pictures. (??)
The acquisition memory would therefore be elsewhere (Yokogawa specific large flat case)??

The replaced memories have the same references and I checked the welds under a microscope and multimeter )
Components coming from far away... A defectous, fake copy, one can imagine everything

cdt

[coromonadalix]

and you started another thread

[GGMM]

Hello,
Yes I have created another topic. Yes, I understand that this can be complicated to follow
Here is the link:
https://www.eevblog.com/forum/repair/measurement-on-memory-with-multimeter/
but was specific on testing memories...

So:
I come back to this subject because it concerns the DSO Yokogawa DL1640 directly.
As a follow-up to all my tests on memories, I will explain what I did this afternoon.
I changed the U911 memory and did a power-up test.
And there, miracle, the error in 753 in red on the whole screen no longer appears.
All 4 channels appear functional!!!
If I go to the calibration menu, it works perfectly.
---------
But, inevitably, there is something very strange!!
The front panel indicates DL1640, therefore designed for a memory length of 8MB
The config indicates a memory length of 32MB and a model 701620  (See picture) The label on the cover indicates a model 701610 (8mb) in phase with the inscription of the front face (LD1640).
And what’s amazing is that the acquisition error when doing the memory test is on all 4 channels now!!!
The version looks old 1.2       Most recent 1.53
see here:
https://tmi.yokogawa.com/fr/library/documents-downloads/firmware/dl1620dl1640dl1640l-digital-oscilloscope/

The firmware looks identical for both models.
Now I don’t know what may have been "cobbled together"

There is a card reader, so if I want to make an update I have to buy a card. I have to look into how it works?
I’m thinking about what to do next
I’ll get a can practice with (Lots of buttons and functions) LOL
cdt

[shakalnokturn]

So, does that mean that it is more - or less working?

Just curious does your acquisition board have B8050MD or B8050ME model checked?

It could be as simple as a setting in a service menu. How to get to it though... Some older model service manuals could give hints.

Now I don’t know what may have been "cobbled together"

If it looks anything like attached photo it's more "cobbled apart" 

[GGMM]

Hello Shakalnokreturn,

I will show again (Very simple) and note the PCB’s references.
A priori I had not seen a rider to pass 8MO 32 MO
It is true that for my first tests I had put "Zero" the backup battery , but I think it does not play.
There may be a hidden menu. (Key combinations at startup). We find the service manual of 1740, I will look

Yeah, that’s the one that was on E..y. As I had seen on forums, that a calibration error was more due to leaky capacitors, I tried
I restored and painted it in blue except the front (which remains quite yellow) because there are screen prints. LOL.
A priori for my first tests I notice that the screen is divided into 4 zones, one per channel.
It’s relatively small per unit.
I’m wondering if there’s a way to use the full screen for two views and see if we can superimpose two signals besides the Zoom. This is done very easily in analog.
Good to study all functions..

[GGMM]

Hi,

It seemed to me that I had noted this information.
CPU  B8050MA
ADC  B8050MD

cdt

[GGMM]

Hello,
I’m coming back to you on this DL1640.
It seems to be working, but I find that there is noise on the displayed signal.  See the video.
Since my repair all channels are ok but before only channels 3 and 4 were functional ..... but I didn’t pay attention if there was noise!
I don’t have experience with DSO, but you can confirm that this is not too normal.
I have at this moment only one hypothese of work: The operation seems to have become operational at the change of the 3rd memory of a bank of 4.
The references are the same, but I’m sure they’re not the same lot fabrication . I don’t know if that’s going to have an impact or if the fourth should be changed for that
Unless: Bad weld or something.
Your advice is valuable.

cdt

[shakalnokturn]

Although your photo isn't saying much as we don't know the vertical sensitivity that looks normal to me for a DSO.
Have you re-attached the shielding on the frontend / ADC section?

Try coupling all the inputs to GND and turning vertical sensitivity right up that should give you a better idea on abnormal noise.

For the acq. RAM if the replacements are at least as fast as the originals there shouldn't be a problem, if there is a problem I'd expect it to show at highest sample rates if anywhere.

If you bought a set of 5 RAM IC's on eBay or Aliexpress you have no idea what you really bought, just keep that in mind if it no longer works sooner or later.

[GGMM]

Shakalnokturn,

Thank you for your answer.
For purchases on A...x or E...y, there are things I’ve had for ages that work.
The advantage is that there are no minimum purchases like on other sites that sell components. Well, in short...

To talk about something else, YES it made me tilt after the post, the DSO is open, so the shielding under the ADC is not set for now that can play.
I will see this

I put you the PCB references as requested. (See above)
 If we can lift the doubt for the RAM 8 or 32 M/ channel. Please give me your answer
Otherwise, I did not find a soft option of choice between the 8 and the 32.
There is an option by holding the reset button and do the power up, but this is more to reset the internal user settings.
So it remains a mystery between this model and its size of memory in the acquisition card, but there is always an explanation.

NB: in a menu you can choose an acquisition sockage option that goes from 10K, 100K, 1M, etc and 32M (single), so it seems consistent.
Ha! ,If technicians from YOKOGAWA could read our posts...

Cdt

[GGMM]

Hello,

Regarding noise, watch this video.
How the passage of 40 years of analog makes you ask questions about digital (especially noise). LOL



cdt

[GGMM]

Hello

Victory, everything goes back to normal
The memory test is good
The overview system indicates a 7610 model
By changing the 3rd memory, there was a short micro circuit between pins 42 43 of the chip

The subject can be closed.
cdt