Genuine Dallas SRAM IC Chip DS-1225AD-150,

Tek Part #  156-2991-00

Preloaded with Standard  Calibration Data For Tektronix 2445B, 2455B, 2465B or 2467B Oscilloscopes

REVISION DEC 15 2020

DS1225Y is no longer in Production, as such we use DS1225AD or DS1225AB which are still in production 

Tektronix 2400B series oscilloscopes with SMD Controller Board ( 671-0965-XX ) use a SRAM Memory chip to store all  Calibration related
parameters, these Chips have an internal Lithium battery keeping the data safe   during absence
of power According to Dallas Semiconductors datasheet  Battery has a usable life span of 10+ Years

When the battery fails, all calibration data are lost, and you will get a Test   04 XX boot error
& a garbled display with ??? on the lower part of readout

The Chips we supply Are Genuine Dallas made Parts with Very recent production date Codes and Purchased Directly From  Farnell UK
Of course We do not use any of the cheap counterfeits you may find at ebay   selling at rock bottom prices

As these chips, even if they work, The internal battery  will most likely fail within a few days

Chips will be pre-programmed According to your Oscilloscope model with  standard calibration data
Preloaded Calibration data will cover Basic Instrument configuration ONLY

You will Have to state your Oscilloscope model  when you order

Data Pre-loaded Will Not Cover Instruments with Options 05 or 06  Installed

If your Oscilloscope has either or both these 05 or 06 options installed, you   will have to calibrate options manually as per
service manual calibration instructions, otherwise a 82 error will be shown During Boot

Once the Chip is replaced, all calibration related errors will clear,
Although for most non critical applications standard calibration data will be ok
( readings accuracy close to 98% Depending on components tolerance )
More than enough for most applications
If However you want to meet strict specifications, a complete oscilloscope   recalibration may be needed

Please Note

Replacing the SRAM Chip will Only fix Calibration related Errors, like error Codes  04-XX
will not Fix 05-XX errors, these are due to Controller board DAC circuitry   failure

If your Oscilloscope Gives a 05-XX error, Controller board will need repair, you can contact Qservice if you wish 

to arrange for a controller repair service, in this case we may be able to save your calibration data as well 

and Re-program to the New SRAM 

Please Use The Supplied IC Socket To Mount The New  Chip DO NOT Solder The chip Directly to the board