Tektronix TDS3BAT rebuild - Page 1
Forum section: electronics / repair

author: graybeard
author_rank: Frequent Contributor
timestamp: October 31, 2020, 05:25:57 am
content: I am rebuilding a Tektronix TDS3BAT NiCd battery pack. This component was in series with the string of ten D cell NiCd batteries. I believe it is a PTC resealable fuse. It measure 0.08 Ohms with Kelvin test clips.Is it a PTC?What brand is it?Where can I find a spec sheet?Thank You,Chris

author: graybeard
author_rank: Frequent Contributor
timestamp: October 31, 2020, 05:38:50 am
content: The date code on the chips on the circuit board in the TDS3Bat are from 2001.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 31, 2020, 06:10:26 am
content: Yes, most likely.This is quite similar:https://www.digikey.com/en/products/detail/littelfuse-inc/RGEF700-2/5029786Possibly the G700 series is discontinued? May be able to find a datasheet on an archive site. Brand is née Raychem.7A is a reasonable rating for D cells, and ten in series needs at least a 12V rating.FYI, your images don't show in Chrome, at least on my current configuration.https://blog.chromium.org/2019/10/no-more-mixed-messages-about-https.htmlSuggest enabling HTTPS or migrating to a server which supports it.Tim

author: graybeard
author_rank: Frequent Contributor
timestamp: October 31, 2020, 05:36:55 pm
content: Quote from: T3sl4co1l on October 31, 2020, 06:10:26 amThat looks like it!

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 02, 2020, 03:50:19 am
content: Quote from: graybeard on October 31, 2020, 05:36:55 pmMaybe it's a normal fuse or thermal contacts?

author: MarkL
author_rank: Unknown
timestamp: November 02, 2020, 04:55:23 pm
content: I can confirm it's a PTC. It's a Raychem RGE700, 16V, 7A hold.I've rebuilt my TDS3BAT several times over the last 20 years. You'll need to fully cycle the new pack for the battery controller to learn the new batteries.I eventually got tired of rebuilding the pack and went with a 4S 5200mAh LiPo which fits in the battery compartment. I kept the PTC and added a diode to prevent the scope from inadvertently trying to charge it. I keep the battery out of the scope most of the time, and externally charge it as needed. It more than doubles the run time (I get 4 or 5 hours, IIRC) over the original NiCad pack.

author: graybeard
author_rank: Frequent Contributor
timestamp: November 03, 2020, 04:26:54 am
content: Quote from: MarkL on November 02, 2020, 04:55:23 pmI finished the rebuild last night and charged it with a 18V 1.8A power supply today and it appears to work. It stopped accepting current after about 3 hours.I put it in my TDS3012B (TDS3052B) and it runs the scope, but the on-screen battery indicator does not appear to be working.Based on your advice and the TDS3BAT instructions I left it running in the scope tonight so it will fully discharge. I will recharge it again tomorrow and try it again. Perhaps that will make the indicator work.

author: graybeard
author_rank: Frequent Contributor
timestamp: November 04, 2020, 08:20:13 pm
content: I replaced all of the dead Sanyo D 4000 mAh NiCd batteries withTenergy D 5000 mAH NiCdbatteries in my Tektronix TDS3BAT battery pack.I set up a power supply for 18V & 1.8A current limit and charged the battery pack. When fully discharged it starts at 12.93V & 1.8A. The voltage creeps up as the pack charges and after about 4¼ hours it stops accepting current.When I put it in the TDS3052B ("upgraded" TDS3012B) it runs the scope for over 4 hours until it gives up.I have done three full charge and discharge cycles. The battery charges reliably, and the scope seems to run great except for the on-screen battery indicator. It always shows an empty battery icon.When the battery pack is in place and the scope is plugged in it says it is running on the battery pack and shows the empty battery icon. Before I swapped the batteries in the pack (which were completely dead (0V) it did the same thing and ran from the AC although indicating it was running from the battery. I did not seethe power-plug icon even though the scope was running from AC power. (page 1-12 of the TDS3000B user manual.I cannot tell if the battery is being charged while in the scope. Manuals say it should be charging whenever the scope is plugged in and it needs to charge. I may need to make an extender cable to test this out.I have searched for information on the battery interface and the best I have come up with so far is this one you tube video:https://youtu.be/aJpReXCZWfs?t=108He details the battery connection inside the scope as follows:TOP1 - Ground2 - NC3 - Data Port ?4 - 15 Volts for charging5 - +12 Volts from the battery packBOTTOMIs there an issue with the TDS3BAT working in TDS3000B series scopes? The TDS3BATB & TDS3BATC are both Li Ion designs. I am tempted to just to declare victory now since I can charge it and runs the scope for almost 4 hours and I only need it for an occasional floating measurement. I now have a 500 MHz battery powered scope.

author: graybeard
author_rank: Frequent Contributor
timestamp: November 05, 2020, 06:43:59 am
content: Here is a photo of the new batteries installed in the TDS3BAT and the old batteries on the bench. You can click on it for a larger version.Chris

author: MarkL
author_rank: Unknown
timestamp: November 08, 2020, 08:10:07 pm
content: I have a TDS3054, so I can't vouch for compatibility of the TDS3BAT in the B series scopes. But it would surprise me if it didn't work.Before cycling, my rebuilt pack also showed no charge.When the scope is plugged in, it takes about 10 or 15 seconds for the "plugged in" icon to appear.One thing you could try is to disconnect then reconnect the battery controller to reset it and cycle the pack again. I recall having having an issue that the controller was confused about running on battery vs. AC, and it also thought the charge in the pack was critically low and shut down the scope when in fact the batteries were fully charged. A reset fixed it.To check if the scope is charging the pack, you could measure the voltage across the string of cells and compare with the scope plugged in and then unplugged. The scope will charge the pack at a maximum rate of 250mA so you will some voltage difference, or you can measure the current directly if you have a DC current probe.Otherwise consider declaring victory and move on. You're already doing about 2x better than any of my re-build attempts. Four hours is great. Maybe I was using lame NiCad cells.FYI, I posted a photo of my LiPo mod a while ago (diode was not installed yet):https://www.eevblog.com/forum/repair/tektronix-tds-3014b-power-supply-by-pass/msg767729/#msg767729I did not use the +15V or data battery terminals, so I can't confirm those functions are correct.

author: texaspyro
author_rank: Super Contributor
timestamp: November 09, 2020, 12:58:28 am
content: If you have a TDS2BAT,,, they have been recalled for safety issues. Tek is still replacing them for free.

author: MarkL
author_rank: Unknown
timestamp: November 09, 2020, 01:40:01 am
content: Quote from: texaspyro on November 09, 2020, 12:58:28 amI don't think there is a TDS2BAT, but there is TDS3BATB recall that's been out for at least 10 years:https://www.tek.com/service/safety/tds3000bThe TDS3BATB is a lithium ion battery. We're talking about a rebuild on a TDS3BAT which is NiCad based.

author: graybeard
author_rank: Frequent Contributor
timestamp: November 09, 2020, 04:54:57 pm
content: Quote from: MarkL on November 08, 2020, 08:10:07 pmI'll try disconnecting it and trying again. I have fully power cycled the battery 3 times already and it has not helped.

author: Dave Wise
author_rank: Regular Contributor
timestamp: October 30, 2021, 09:51:14 pm
content: Quote from: texaspyro on November 09, 2020, 12:58:28 amNot to me they wouldn't. They claim they can't ship them in Oregon. I don't believe it.

author: SMdude
author_rank: Frequent Contributor
timestamp: October 30, 2021, 11:12:57 pm
content: Shipping batteries that contain Li-ion is becoming stupid!I bought a used tdsbat3b on ebay. It was sent by the "Global Shipping Program". Apparently it was a prohibited item and could not be sent.I got a refund and no batteryYet I can buy a laptop battery from china and that will be sent just fine, yet a Tektronix battery, not ok...Does anybody have any photos of the board within the Tek batteries? I am specifically interested in the battery fuel gauge ic as I would like to roll my own li-ion tek battery and having a working fuel gauge would be novel.I know I don't "need" the fuel gauge, but as I am going to go to the trouble of designing a board with a 12v charger, it would be nice to include if possible.Even a photo of the older ni-cad board would suffice.Cheers

author: Dave Wise
author_rank: Regular Contributor
timestamp: October 30, 2021, 11:28:07 pm
content: Not a photo, but I scoped the connector.Pinout:<locating key>MINUSNCDATAPLUS-TO-CHARGERBAT-PLUSThe DATA line uses the Unitrode/Benchmarq/TI "DQ" 333 bit per second protocol.I believe the TDS3BATB (maybe TDS3BATC too) contain a BQ2050 gas gauge chip. TDS3BAT would be an older BQ20xx meant for NiCd. Look at the TI site, filtering for fuel gauges using DQ protocol. Not SDQ or HDQ or I2C or SMBUS.When the scope is running from mains and charging the battery, once every second it reads six registers, 0x3 (Nominal Available Capacity High byte), 0x17 (NAC Low byte), 0x3 again (in case it rolled over I guess), 0x1 (FLGS1), 0x2 (TMP) and 0xB (VSB - battery voltage). NAC increments approximately every five seconds. The temp field of TMP reads a constant 7 (30-40C) while the gas gauge field incremented once in about a half hour. FLGS1 returns 0x94 indicating Charging and Capacity Inaccurate. I don't like CI but maybe the scope doesn't care.The gauge's reply timing is unstable, I got good results using B Trigger in Event Count mode. Commands are 9 negative edges, returned data is 8 edges. So you can scroll through the commands and replies by setting the event count.

author: SMdude
author_rank: Frequent Contributor
timestamp: October 31, 2021, 09:57:33 am
content: Excellent, thank you so much!

author: coppercone2
author_rank: Super Contributor
timestamp: October 31, 2021, 03:46:14 pm
content: Lol, I soldered a bunch of tabbed NiMH batteries and put them in the place of a missing NiCAD pack that is in some equipemnt I use like once a year max, since it would NEVER be charged on a NiCAD. Anyway, I charge it at like 1/10ish C on a lab constant current power supply and it seems to be holding up alright, after 6 months I got the expect runtime out of it, and after recharge without disassembly or modification everything seemed in order. Its probobly not ideal but I just slapped it in there.. kind of interested to see what will happen in 2-3 years when the batteries are aged and improperly charged a few more times.

author: Dave Wise
author_rank: Regular Contributor
timestamp: October 31, 2021, 08:15:56 pm
content: About my TDS3BATB that reads Capacity Inaccurate: after a complete discharge and charge, now it reads Capacity Inaccurate + Valid Discharge. I expect CI (and VDQ) to go away after one more full discharge, meaning the gas gauge is calibrated.If you want fast charge but don't have a TDS3CHG/TDS3ION, it looks like a normal bench supply will do. I set mine to 18V with 1.8A current limit, based on the TDS3CHG spec sheet. Connecting it to the TDS3BATB external charge coaxial connector, I see about 1.3A which tapers after a couple hours then shuts down to a few tens of mA at charge complete. I will probably charge them this way - outdoors - if Tek continues to refuse my packs for recall. And store them in a metal box. That should be safe.To extend battery life I will store them only about half-charged.On initial installation in a scope running off the mains, I see the usual six register reads, then this, once:read 0x7 (PPD Program Pin Pull Down) == 09 i.e. Prog1 and Prog4 power-on straps were lowread 0x8 (PPU Program Pin Pull Up) == 80 i.e. no power-on straps were high, so Prog2/3/5/6 were all in 'Z' state(By the way, one thing this means is the cells are coke anode, not graphite anode.)write 0x8c (VTS End Of Discharge Threshold Select) = 0xA2 i.e. 10.63Vread 0x0c (VTS) to confirm it is 0xA2(The exact value was probably stored in RTC RAM and depends on what the scope read on VSB just before it died.)For more info, see "Battery voltage and pinout for Tektronix TDS 3000 series oscilloscope",https://www.eevblog.com/forum/testgear/battery-voltage-and-for-tektronix-tds-3000-series-oscilloscope

author: Dave Wise
author_rank: Regular Contributor
timestamp: December 24, 2021, 08:21:39 pm
content: Quote from: Dave Wise on October 30, 2021, 09:51:14 pmUPDATE: Tek finally replaced my battery packs! (After I filed a Consumer Protection complaint with Oregon Department of Justice. I don't know if that's what got them off the dime, or if they were just slow. But eventually a manager got involved and overrode the script.)

author: JimLev
author_rank: Contributor
timestamp: March 29, 2022, 02:50:57 am
content: Thanks for posting this, just found it. I’ve got a TDS3054B, I’ll have to pull the battery out tomorrow to see if’s one that is recalled.Getting a brand new battery for free would be nice.

author: JimLev
author_rank: Contributor
timestamp: March 29, 2022, 04:58:21 pm
content: I pulled the battery module out and opened it up today. Didn’t pull the individual cells out, couldn’t see any writing on them.The cells were the size of the 18650 cells so I’m hoping they are the lithium ones.The modules had TDS3BATC on it so I’m pretty confident they aren’t NiCads.

author: Dave Wise
author_rank: Regular Contributor
timestamp: March 29, 2022, 06:51:08 pm
content: TDS3BATC is current production. TDS3BAT was nickel-cadmium, TDS3BATB and TDS3BATC are lithium 18650. TDS3BATC has a new design for the slow charger and an extra layer of protection, added when a TDS3BATB burned at a customer site. It still doesn't have a cell balancer. More info at the thread whose URL I posted earlier.

author: cunningfellow
author_rank: Regular Contributor
timestamp: June 25, 2024, 07:38:52 am
content: Anyone looking to replace the NiCad D cells in a TDS3BAT should take a trip to IKEA.The Ladda 2450mA cells (OEM Panasonic Eneloop Pro) work out at $60AUD for 20 cells (5 packs * $12).Weld them up in a 10S2P and they fit in the bulge part of the TDS3BAT no problem.You end up with 4.9AH of juice. Which is inside the 4..6AH range the coulomb counter chip thingy expects and a whole lot cheaper than any D cells I could find to buy.I 3D printed the holder from a file I downloaded from Thingverse

author: bingo600
author_rank: Super Contributor
timestamp: June 25, 2024, 08:24:05 am
content: Quote from: cunningfellow on June 25, 2024, 07:38:52 amNeat solutionBut isn't there a charger issue ?I'm not an EE, but think i read that NiMH was not happy with a NiCD charger.Was it the "trickle charging" that was too high or ....Just a "concern" ...

author: cunningfellow
author_rank: Regular Contributor
timestamp: June 25, 2024, 12:42:52 pm
content: NiMh will die an early death if left constant trickle charging. They should be turned off at delta-peak.I will not be leaving this NiMh battery in the scope all the time.

author: Dave Wise
author_rank: Regular Contributor
timestamp: June 25, 2024, 02:43:19 pm
content: How is the TDS3BAT charger wired? Is it a chip that can be jumpered to support NiMH?

author: cunningfellow
author_rank: Regular Contributor
timestamp: June 26, 2024, 12:15:36 am
content: Personally have no idea. I just did a battery swap and am happy to not have it on charge all the time. I rarely need it as a portable so just leave it out.I think from memory someone here has had a closer look at the battery and the protocol.

author: Dave Wise
author_rank: Regular Contributor
timestamp: June 26, 2024, 12:54:55 am
content: That might have been me. If by protocol you mean the comm between pack and scope, I once got knowledgeable enough on the TI BQ2050 gas gauge to decode it on my own scope, but it's beside the point, which is the charger. In the TDS3BATB that's a MAX1737 (high power) and a BQ2057 (low power). They could not have used that in the TDS3BAT because the BQ2057 is for Lithium only.

author: cunningfellow
author_rank: Regular Contributor
timestamp: June 26, 2024, 02:35:15 am
content: Sorry, Just popped it open to take some photos for you.Front of board has Battery Fuel Guage, Quad OpAmp, Linear Reg and a few FETsBQ2014LP324LM29364435 (Q2 SO8)50WQ04Back of board has µC, comparators and a large FETPIC16C54ALM339LM339M50P03I am going to guess the charging is done by the PIC and I think because it has a C rather than an F in its name it is write once isn't it.Doesn't look like an easy mod to change the charging logic

author: Dave Wise
author_rank: Regular Contributor
timestamp: June 26, 2024, 03:05:23 pm
content: Thanks for the pictures!We see that Tek OEMed the board from PowerStream Technology in 1998.The 50WQ04 is a schottky power rectifierThe 4435's are FDS4435 30V 9A P-channel power mosfetsThe M50P03 is a 50A N-channel power mosfetThe FZT789 is a PNP power BJTNo inductors so no switching power supply, I bet that the big mosfetand/or the BJT are wired as linear pass elements with the PIC pulsing themto limit power dissipation.You are correct that the PIC16C54A in plastic package is OTP, so we aren'tgoing to be changing the program or even seeing it.One thing that is still easy is to insert an ammeter and measure thecurrent at full charge. It might be small enough that your cellscan tolerate it.