TEK2465BCT that does NOT have Dallas chip - Page 1
Forum section: electronics / repair

author: tkamiya
author_rank: Super Contributor
timestamp: August 27, 2018, 05:59:08 pm
content: I have been having problems addressing "flat tire" (empty battery and lossed cal data) issue with my tek2465BCT. A kind gentleman from this board sent me a bin file with his data. Problem I face now is, mine does not have a Dallas chip. It has a caramel shaped battery called "Deeper" and a CMOS memory.Initially, I was going to de-solder the Dallas chip, load the bin file (I bought a programmer) and be done with it. But now it isn't even possible. Service manual is mum about loading data.Does anyone have experience with this and willing to share?

author: tkamiya
author_rank: Super Contributor
timestamp: August 28, 2018, 02:05:59 am
content: Right next to the battery, there is a SRAM, D4364C. According to datasheet, this is a 64K SRAM of low power consumption variety. I wonder if I can remove this, hook up a small battery 3.6V and a protection diode, to VCC and GND, write data, and plug it back in, then remove VCC?Of course, I will replace the dead battery on the board while this is taking place.

author: alpher
author_rank: Frequent Contributor
timestamp: August 28, 2018, 02:40:18 am
content: You're taking a quite a bit of risk, I gather you'r situation to be very similar to mine in this thread:https://www.eevblog.com/forum/testgear/just-got-a-2465a-couple-questions/msg1436720/#msg1436720

author: tkamiya
author_rank: Super Contributor
timestamp: August 28, 2018, 04:33:50 am
content: Well, my risk is, my scope will blow up and move Earth's axis off kilter, causing mass extinction. Either that or end up with a useless scope.Yes, my situation is very much like yours. The BatteryKeeper actually reads 3.5x volts. However, I am getting the error message indicating calibration data is messed up. History of this scope is unknown so anything is possible. My task now is, somehow load the bin data someone on this board kindly sent to me. I really don't want to send it to calibration, until I know for sure, it works.My plan of action is to power up the SRAM with a battery taking care of reverse current, then replace it with a socket.Using similar scheme, write to the SRAM via programmer while backup is still attached.Replace onboard battery while I'm at it.Replace that into socket and remove the temporary battery.That should work.....I like your option, too, using clone of DALLAS but I think that'll be same as what I'm doing rather crudely.But in my scenario, nothing seems to be actually broken or exhausted. Just corrupted. If there IS a way to feed data into the SRAM, I can bypass all this hardware surgery.

author: tggzzz
author_rank: Super Contributor
timestamp: August 28, 2018, 08:53:06 am
content: Quote from: tkamiya on August 27, 2018, 05:59:08 pmWhat makes you think the calibration data forhisscope is relevant toyourscope?

author: BradC
author_rank: Super Contributor
timestamp: August 28, 2018, 12:42:04 pm
content: Jump on the tekscopes2 list and find someone vaguely close that'll help you cal it. They're not actually that difficult to calibrate with a few bits of kit.

author: tkamiya
author_rank: Super Contributor
timestamp: August 29, 2018, 12:44:41 am
content: Quote from: tggzzz on August 28, 2018, 08:53:06 amAbsolutely nothing. I just want to see if it's acceptably close. Once I know it works error free, I'm going to get it cal'd.

author: tkamiya
author_rank: Super Contributor
timestamp: August 29, 2018, 12:47:19 am
content: Quote from: tkamiya on August 29, 2018, 12:44:41 am

author: tkamiya
author_rank: Super Contributor
timestamp: August 29, 2018, 12:53:10 am
content: Alpher,On your thread, you've replaced the Dallas chip, then you also kept the KEEPER battery. Wouldn't that cause Keeper to drain Dallas chip? (well, I mean clone of it)

author: alpher
author_rank: Frequent Contributor
timestamp: August 29, 2018, 01:01:14 am
content: Quote from: tkamiya on August 29, 2018, 12:53:10 amI lifted one leg of one of the separation diodes, left Keeper connected as there is a circuit monitoring its voltage in 2465A, I gather yours may be similiar.