TEK 2467B Odd failure

[FlyingHacker]

I believe the unit specific calibration constants are stored in each chip. So you really need to read the old values and copy them, or do a full recal.

I like this idea of replacing the battery with an external one. Got any pics/videos of this?

[james_s]

I don't remember where I originally saw it, on a forum for older Sun workstations I think. I've done it on the NVRAM chip they use since there is a peculiarity that prevents the supposedly equivalent modern replacements from working. If you put the chip in a vice and file into the top you will find the battery, but read the contents out first since removing the battery will cause them to be lost.

Youtube to the rescue:

[jonpaul]

Hello all:

Looking deeper on A5 I found other corrosion damage near the SMD electrolytics, and 3 SMD tantalum caps known to fail

Here is a good link on Groups.io about recapping the PSU and A5 with part nos:
https://groups.io/g/TekScopes/topic/2465b_power_supply_sprague/974763?p=Created,,,20,1,20,0::RecentPostDate%2FSticky,,,20,2,900,974763

scroll to Tothwolf 10/15/15   #121345    On Thu, 15 Oct 2015, vdonisa

1/ It seems A5 underwent several revs and versions of mod, the SN is critical to locate the coprrect doc.

2/ Lytics are 5mm dia and bypass +/-15 and +5, alsong with nearby 100 nF monothlyics.

3/ As A5 has ADC, DAC and demux for FP controls, corrosion on the board can produce very odd symptoms.

4/ A5 is the ONLY SMD board, all others are thru hole.

5/ Replaceing the Dallas NV RAM: Maxim took over Dallas Semi,  and its on DigiKey.
http://datasheets.maximintegrated.com/en/ds/DS1225Y.pdf
As a 28 pin DIP its easy to swap, especially if you add a socket.

My BIG issue: I have NO programmers for NVRAM, and recalibration is a huge deal. Anyone out there have the capability to read and program the NV RAM?

 As I have several with these same NVRAMS, any help is appreciated.

Cheers,

Jon



 

[jonpaul]

WOW! What a great link and work!

http://www.worldphaco.com/uploads/TEKTRONIX_2465b_OSCILLOSCOPE_CALIBRATION___REPOWERING_THE_DS1225.pdf

Enjoy,


Jon

[james_s]

The programmer is not a big deal, I have a TL866 that handles all this sort of stuff, they're cheap enough that it's worth having one around for that odd time you might need to program or dump a memory IC. As an added bonus it will program lots of different PIC and AVR micrcontrollers, and odd stuff like GALs.

http://www.ebay.com/itm/High-Speed-TL866CS-Programmer-USB-EPROM-EEPROM-FLASH-BIOS-AVR-AL-PIC-/191816776888?

[jonpaul]

Hello all: Just getting to order the programmer. All the TL866 on epay seems the same, and from China:

"High-Speed-TL866CS-Programmer-USB-EPROM-EEPROM"

Anyone have experience with these? Instruction/software in English? Pitfalls to use on the Dallas DS1225?

Any tips are appreciated,


Cheers,

Jon

[mtdoc]

Hello all: Just getting to order the programmer. All the TL866 on epay seems the same, and from China:

"High-Speed-TL866CS-Programmer-USB-EPROM-EEPROM"

Anyone have experience with these? Instruction/software in English? Pitfalls to use on the Dallas DS1225?

Any tips are appreciated,

See this thread

[Satbeginner]

Hello again: Anyone had experience with QService Greece lately for TEK parts?

Need the Dallas NV RAM and an odd knob shaft etc.
377-0512-03 INSERT,KNOB


156-2991-00 Dallas NV RAM DS-1225Y-200 64K Programmable NV-SRAM


They seem to have no stock on the NV RAM: Looking for one programmed....and with a fresh not 20yrs old date code!

Any tips?


Cheers,

Jon

I recently bought a replacement Dallas at Mouser, and I got one with a 1614 timestamp.
But, this is the newer kind with the battery disconnected till the first use, so I should be OK for the next 10-25 years... :-)

Un saludo,

Satbeginner (Leo)

[Satbeginner]

Hello all: Just getting to order the programmer. All the TL866 on epay seems the same, and from China:

"High-Speed-TL866CS-Programmer-USB-EPROM-EEPROM"

Anyone have experience with these? Instruction/software in English? Pitfalls to use on the Dallas DS1225?

Any tips are appreciated,


Cheers,

Jon

Hi,

I just finished a repair and general overhaul of a 2465B, and used the TL866 to read/write the Dallas.

Read here: https://www.eevblog.com/forum/repair/2465b-tektronix-repair-missing-a5-smd-version-board/

I found one little thing: choose the right type of Dallas in the MiniPro program! not the "DS1225 TEST", but the "DS1225 R/W"
Any action with the first chiptype will erase your existing chip loosing the calibration... (happened to me..  , but, I had to calibrate anyway, because my A5 came from another 2465B )

Succes!!

Satbeginner (Leo)

[Old ET]

I found a post that shows how to replace the Dallas with a FRAM (no more battery). You do have to save the BIN file to a computer with a programer 
(I used a GQ-4X V4 from MCUMALL in Canada and it worked great) I had the Dallas DS1225Y where I had to go in through the bottom and remove epoxy to get to pin 7 of the Dallas 1218. Once I had the pin exposed I connected a Lithium Button Cell between pin 7 of the 1218 and pin 14 of the 1225 module (ground). By doing this I saved my programing in the 1225 and was able to extract the BIN file and save it on a PC. I then used the FR16W08 soldered to an adapter board and placed the program onto the Fram. Just follow the directions in this link:
http://www.worldphaco.com/uploads/TEKTRONIX_2465b_OSCILLOSCOPE_CALIBRATION___REPOWERING_THE_DS1225.pdf

I have not been able to turn my scope (2467B) on as I need a Fan and am waiting on that. I did do a complete recap (A1, A2-A1, A3, A5, A9) so if everything is Ok once I have the Fan installed I will apply power and check for smoke signals. LOL Hope this helps, as I have found great information on this site and others.

GR