Products > Test Equipment
problem with battery replacement in a tektronix 2445b oscilloscope
jsblues81:
What do you think of using a FRAM instead?
bdunham7:
--- Quote from: jsblues81 on February 23, 2022, 09:03:02 pm ---What do you think of using a FRAM instead?
--- End quote ---
Somebody else should answer that since I haven't done that one of these. I think it is commonly done, but I've no idea how much more work it is. If the Dallas NVRAM is available, I'd probably just replace it and run a calibration. Look for the very long Tek 2465B teardown thread here or just do some searching--you'll find plenty of info on it. You also want to replace the SMD capacitors on the A5 board and clean it.
grumpydoc:
--- Quote from: bdunham7 on February 23, 2022, 08:08:48 pm ---Is that a drop-in replacement for the DS1225Y? Have they been available this whole time?
--- End quote ---
I believe so, it's the Maxim part and you need to go for the "AD" suffix which has the same supply voltage spec as the original "Y" (5v ± 10%); anything faster than 200ns should be OK.
--- Quote from: jsblues81 on February 23, 2022, 09:03:02 pm ---What do you think of using a FRAM instead?
--- End quote ---
It's worth reading the TekScopes mailing list archived postings (and, I believe, also threads passim on eevblog) about this. The problem with the FRAM is that there's no protection from spurious writes on power up/down as the DS1225 handles this internally. the result is that quite a few people have reported corruption of cal data when using an FRAM.
I originally bought an FRAM to put in the 2445B that I repaired recently but having read through the old posts I decided to go for the Dallas chip instead.
jsblues81:
Hey guys...thanks loads for the support y'all gave to me but I've decided to pack this up and sell it on ebay as non-working or for parts to re-coup some of money spent and look for another 2465 which as I have read is very much superior and attempt to repair it now that I a little more knowledge..thanks to you then I had previous..I own 3 working 465b's and was just looking for something more up to date without going thru hoops to get it...wish me luck?
jsblues81:
Hey y'all...its been awhile. I just purchased a 465b with serial number starting with 062.... so its a little later than my other ones. The image on the screen does not go all the way to the left edge and all the way to the right edge. It comes 1 graticule short on both right and left edges of the screen. Does anyone out there know whats the cause...hv problem or worse. The -2450v is present and even a slight bit high...all the low voltage supplies are fine with little or no ripple on any of them. Please advise...thanks in advance.
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