| Products > Test Equipment |
| High failure rate of Maxim Integrated DS1245YP-100 chips on TDS7000 scopes |
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| wraper:
--- Quote from: Jwalling on March 23, 2017, 11:05:45 am --- :=\ --- End quote --- Ok, I'll tell a story of one little ST SNAPHAT M4T32-BR12SH6 battery, which is snapped on SOH-28 IC. "A good type" in your opinion. Happened with me a few months ago. So one 10yo device which weights a ton failed. I traveled from Latvia to Ukraine, 7 hour flight including transfer + 5 hours by car to the destination. So I figured out that Eurotherm 2704 controller failed. I had a user config backup I made few years before that but no factory config backup. So after a config restore, controller worked only partially. Factory config is dependent on modules installed, and part number (config) is long and with many variants. So there is no chance restoring it. I took the controller and traveled back to Latvia. Sent it to Eurotherm/Shneider Electric in Germany to get factory config restored. We paid EUR 800, received the controller back, restored user config and repeated my travel to Ukraine. What a f...ing bless. All of the time that device was down. |
| Kjelt:
--- Quote from: Jwalling on March 23, 2017, 10:27:27 am --- --- Quote from: Kjelt on March 22, 2017, 11:05:01 am ---You blame Maxim but you should blame Tek for using that part that has a fixed lifetime of 10 years after production till failure and they did it on purpose because they want you to buy a new scope by then and trash the old ones. It is this short term environment unfriendly production way of thinking that is to blame IMO. --- End quote --- Err... You don't get it. This is the snap-cap version with a replaceable battery, not the PDIP part. And these are semiconductor failures, not the battery in any case. --- End quote --- Ok I have a Tek scope with the sealed versions for RTC and BB-SRAM , there it was a valid argument. |
| Jwalling:
Getting away from the painfully obvious "batteries eventually go boom when powering stuff" The bad chip has a date code of 0042GH (2000) and a lot code (?) of 120737. The replacement chip draws 20nA. Since my original post I made a kluge adapter that would allow me to power the NVRAM externally and monitor the current draw when powered down so I won't have to solder wires to the the Dallas chip. I don't think I'll ever trust these parts again so will probably make this test SOP on incoming TDS6000, TDS7000 or TDS/CSA8000 scopes or any other equipment that uses them if the battery is dead. The DS9034PC snap-cap battery replacement is $10.18, once again, from Digikey. It contains a BR1632 130mA lithium battery. What a great deal for $10, when the battery is $2! It has 2 solder tabs 180 degrees apart: https://www.digikey.com/product-detail/en/panasonic-bsg/BR-1632A-FAN/P022-ND/273642 (No stock) Doesn't seem to be a common part - Mouser has none as well. Could probably schlock this one in: https://www.digikey.com/product-detail/en/panasonic-bsg/BR-1632A-HAN/P023-ND/273643 |
| swperk:
My TDS7404 failed to boot after having been in storage for several years. The PPC console output showed that the DS1245YP-100 was failing the walking 1's test. The snap-cap battery was dead, so I replaced it, but there was no change. I discovered that the DS1245YP-100 was putting a high drain on the snap-cap battery and that it had the same date code and lot number as @Jwalling's. I ordered a new DS1245YP-100 from Mouser, installed it, put on a fresh snap-cap battery, and now all is well. Chalk up another failed TDS NVRAM! |
| james_s:
--- Quote from: nctnico on March 21, 2017, 01:43:07 am ---It could be interesting to replace it with a small PCB containing an FRAM. This shouldn't be hard to make and the 128k * 8 FRAM ( FM28V100-TGTR from Cypress) costs around $20 in single quantities. --- End quote --- It might be worth trying, but none of the gear I've tried retrofitting one of those into has worked with it except for a pinball machine. They are hardware compatible with standard NVRAM but they require toggling of one of the control lines prior to each write to latch the address or something like that which standard SRAM does not require. There are other parallel NVRAM devices out there though that can be used if the Dallas parts are experiencing a high failure rate. Personally I haven't had any reliability problems with them but they are expensive. Given what these scopes cost when new though I can see why Tek wasn't bothered about using an expensive part. |
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