Fluke 8050A Repair - Page 1
Forum section: electronics / repair

author: Cigarsnob
author_rank: Regular Contributor
timestamp: December 25, 2011, 07:17:45 pm
content: Howdy,I just picked up a fluke 8000A and 8050A DMM from a surplus store yesterday. The 8050A model is the battery option (Connects to mains, but it comes with recharable bat). Well I knew the 8050A DMM needed some repair and when I switch it on, the "bat chg" LED comes on, but the DMM does not work. No LCD display. Although when I switch through the ranges, I do get a flash on the LCD.I plan on buying some new batteries to see if that does the trick, but ideally, I would like to save myself the money and remove the batteries and make the 8050A function off the mains directly. I found one thread saying to just remove the batteries and install some beefy caps with a resistor. Does anyone know if this will do the trick?I found the manual with the schematic and plan on digging into the DMM once I get home after the holiday, but thought I would seek some advise here while I wait.Thanks in advance for any information.Phil

author: Unknown
author_rank: Unknown
timestamp: December 25, 2011, 09:56:57 pm
content: Some circuits use batteries as crude voltage regulators, in that case a cap wouldn't do. If it's just for smoothing, a cap might work found.This postin the TekScopes Yahoo! group suggests some minor circuit modifications (eg. replacing the voltage regulator and removing some resistors) to get the 8000A/8050A working without the batteries, so just putting in a cap may not be sufficient.

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 25, 2011, 11:04:22 pm
content: The battery-operated 8050A-01 uses an LM317 in current-regulator configuration to supply both charging current for the batteries and operating current for the meter. The batteries need to be there to regulate the voltage (roughly 5V). I modified one of my 8050As by removing the batteries and modding the circuit board to use the LM317 as a voltage regulator. It works fine that way.If you need more details on how I did the mod, I can provide them but it will take a few days since I am away from home for the holidays.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: December 26, 2011, 12:14:26 am
content: Modemhead,If it's not too much of an inconvinance, I would appreciate more info regarding the mod you spoke of. I don't mind the wait as I'm also away for the holidays.I should be able to make the mod just by looking at the datasheet of the lm317 and the schematic of the 8050A, but you can't go wrong with having more information.Thank you,Phil

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: December 26, 2011, 03:14:33 am
content: I had a similar instrument that was a constant problem because of the batteries. I didn't use it often enough to keep the expensive battery pack in good shape. I replaced the battery pack with a big aluminum electrolytic cap, shunted with some power zener diodes to imitate the clamping action of a real battery. The zeners have to be sized to take the usually minimum charging current. It probably works better now than it ever did with batteries.

author: grenert
author_rank: Frequent Contributor
timestamp: December 26, 2011, 04:53:56 am
content: Hey, anyone have a spare LCD from one of these? I've got one where I replaced the batteries with modern NiCd (NiMH self-discharge to quickly), but the display was squashed at some point, and it is "blurry".Thanks and Merry Christmas to those who celebrate it!

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 26, 2011, 10:32:11 pm
content: Quote from: Cigarsnob on December 26, 2011, 12:14:26 amIt's now on my to-do list.

author: amspire
author_rank: Super Contributor
timestamp: December 26, 2011, 10:56:11 pm
content: Quote from: grenert on December 26, 2011, 04:53:56 amI may have a working display. I have a non working meter I keep for spares. I well power out up and see if I can get any life out of the display.What country are you in?Richard.

author: amspire
author_rank: Super Contributor
timestamp: December 27, 2011, 06:11:17 am
content: I decided to look at what was faulty in my spare 8050a, and unfortunately, the only thing wrong is the display.I think the display is fine, but there is a problem with the conductive rubber contract strip.The contact with the most problem is pin 1 - the display common.I do have spare Fluke 120v transformers, so if anybody wants to convert from battery to Mains, it looks like all you need is the transformer and about 9 other standard components. All the locations for the Mains supply part are actually on the board under R&D that is only used for the battery version.Richard

author: amspire
author_rank: Super Contributor
timestamp: December 28, 2011, 05:04:45 am
content: This is not a bad alternative to sourcing a replacement LCD display for a Fluke 8050A DMM.http://lous.home.xs4all.nl/fluke/Fluke8050Asite.htmlThe 8050A LCD does suffer from low contrast.Richard

author: Unknown
author_rank: Unknown
timestamp: December 28, 2011, 05:42:39 am
content: This seems like an excellent alternative providing you don't care about battery life. In my opinion LED displays are superior to LCD for basic 8 segment displays. Much better viewing angle and contrast.

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 29, 2011, 04:47:46 pm
content: Quote from: Cigarsnob on December 26, 2011, 12:14:26 amOriginally, U26 (LM317) is configured as a current regulator. When the front-panel switch is off, a 137mA charging current (determined by R26) is provided to the 4.8V battery pack. When the meter is turned on, an additional 104mA (determined by R25) is supplied to operate the meter and continue trickle-charging the batteries. As I recall, the meter required about 150mA operating current. The voltage from this arrangement would probably vary between about 4.8V for a discharged-but-healthy battery pack and 5.6V for a charged pack.Note that this Fluke schematic is in error regarding the LM317 input and output pin numbers.I changed the LM317 configuration to regulate voltage at 5.5V, as follows:Cut two traces at the points indicated.Replace R25 with a wire jumper.Replace R26 with a 150R 0.25W resistor.Add wire jumper from R26 to U26P1.Add 510R 0.25W resistor from U26P1 to C23-neg.This shows the mods from the solder side of the PCB. The upper cut trace is obscured by the resistor lead.Optionally, you can remove the red "Bat Chg" LED DS1, because it will still illuminate when the power switch is off. Note that when the power switch is off, the transformer, rectifier, and regulator are still energized, and will consume some power (but much less than if batteries were installed.)Re-installing batteries after these mods may lead to unfortunate consequences, so you may want to remove the battery pins or somesuch to prevent that.

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 29, 2011, 05:19:10 pm
content: Quote from: amspire on December 28, 2011, 05:04:45 amI've done that one too, but the back side of that LED display is a labor of love. Eh, some people climb rocks for the heck of it, I play with old gear.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: December 29, 2011, 05:27:52 pm
content: ModemHead,Great description. Thank you very much. I will do this mod soon.But before I do, without knowing anything else, do you think the batteries is causing the DMM to not function properly? I had it plugged in for a couple of hours when I first got home and switched the thing on. It worked at that point, but the low battery indicator on the LCD was always on. Then I noticed last night that it worked for a bit and then when I switched it off and back on again, I would get the low battery indicator on the LCD again along with a "1" and then the LCD would fade out. After switching the thing on and off again several times and sweeping through different ranges and voltage/resistor setting, the same result would occur. All of this after the DMM has been plugged in for the past 48 hours.Well thanks again and I really appreciation the tutorial you provided. Hopefully this will get my DMM running again and consistently this time.

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 29, 2011, 05:48:12 pm
content: Quote from: Cigarsnob on December 29, 2011, 05:27:52 pmYou're welcome, happy modding/repairing.Your problem sounds exactly like a dead battery pack. Bad cells will pull the voltage on this 5V nominal supply down far enough that the meter will not operate, or won't operate for long.An alternate, even easier fix, is just to solder in any working sub-C NiCd cells that you have. If you're not concerned about actual battery operation, four 1.2V cells of just about any size will allow the meter to work fine on AC power. Until the cells go bad, as they all do. Smaller cells may get warm on the 140mA constant trickle...

author: Cigarsnob
author_rank: Regular Contributor
timestamp: December 29, 2011, 06:19:29 pm
content: Quote from: ModemHead on December 29, 2011, 05:48:12 pmI don't have any C NiCd cells so I'll just stick with the mod you provided. Thanks again for all your help. I'll post my results in a day or two.

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 29, 2011, 06:45:26 pm
content: Since the transformer and regulator are energized as soon as you plug the meter in, 5.5V or so should appear across U26P2 to C23-negative even before turning the power switch on. You can check your work this way without possibly damaging the rest of the meter if you make any mistakes.

author: amspire
author_rank: Super Contributor
timestamp: December 29, 2011, 10:48:07 pm
content: Quote from: ModemHead on December 29, 2011, 05:19:10 pmThanks for the photo's. It turns out my spare parts 8050A has a dud LCD - the backplane connection is open circuit internally. I have 3 other working ones (got four of them for $25 each), so I am going to do the LED display mod, so I have one meter that works in poor lighting.After seeing your photos, I will make a custom PCB and find a way (I hope) of connecting to the LCD contact row, rather then all that wiring to the display driver IC's. I should be able to salvage some SMD resistors and transistors, and I have ordered the displays and some acrylic filter sheet. Total cost will be about $20.Main reason for doing the work is that in debugging the LCD display, I found out that the rest of the meter works perfectly (I swapped display boards with a working 8050A), and I don't really need a 4th working LCD display at a cost of a new display - something like $50. To get one with with a LED display makes it worth the effort.Richard.

author: amspire
author_rank: Super Contributor
timestamp: December 29, 2011, 11:05:42 pm
content: Quote from: Cigarsnob on December 29, 2011, 06:19:29 pmIf it were me, I would spend the $7 for a set of 4 NiCd cells.http://www.ebay.com.au/itm/4-Sub-C-SubC-Tab-2500mAh-NiCd-Rechargeable-Battery-B1-/130617181876They will die eventually, but you then get another set, and you can run the meter on battery power for a day's work. It is not just the portability issue, then meter has a higher safety rating when running from batteries. Running off battery also eliminates the 40pF Common Input-to-Mains capacitance that might cause a problem while measuring switching circuits.Richard

author: Cigarsnob
author_rank: Regular Contributor
timestamp: January 02, 2012, 07:12:40 am
content: Quote from: ModemHead on December 29, 2011, 06:45:26 pmHey ModemHead,I am having an issue with the mod. I performed the steps that you listed, although my PCB was slightly different than the picture provided. When cutting the trace that connects to U26.1, I had multiple traces (3) ending at U26.1 besides the battery pack. These multiple connections was the transformer, T3, C22, and C34. The cut disconnected those components from U26.1. I take it this is correct, no?Also, after adding the 510 ohm resistor from C23 (negative pin) to U26.1 and plugged in the power cord (after all other steps were performed), I only got a voltage of 4.5V when probing U26.1 and C23 (negative pin), so I ended up upping the resistance to ~650ish ohms to get 5.5V. At this point, I turned it on and nothing appeared on the LCD.I checked my work a few times and I'm fairly certain I did the steps correctly. When I checked the voltages at TP2, 3, 4, and 5, I don't get the voltages as described in the schematic. I was checking these voltages when having one probe placed on C23 (negative pin) and the other on the test points. The voltages observed were roughly 6V (6.5V on some). But then I thought that I may be placing my other probe, (that connects to C23 negative pin) incorrectly so I placed in on the front panel common plug and the voltages on the test points were in the mV range.I don't know if any of what I said provides any insight as to what I did wrong, but any advise would be appreciated.I'll have another crack at it in the morning.Thanks

author: ModemHead
author_rank: Frequent Contributor
timestamp: January 02, 2012, 04:25:18 pm
content: Quote from: Cigarsnob on January 02, 2012, 07:12:40 amYes, the cut should simply disconnect U26.1, leaving the rest of the circuit intact. I've attached a diagram which I hope makes clear exactly how things should be connected before and after, regardless of PCB layout.Quote from: Cigarsnob on January 02, 2012, 07:12:40 amThe 5.5V should be from U26pin 2to C23 negative pin. That is the voltage regulator output. The voltage from U26.1 to C23-neg should be about 1.25V lower than 5.5V, or 4.25V. Your measurement sounds like it was OK to begin with. There should be no need to raise the resistor value, which would lead to an output voltage that is too high.Quote from: Cigarsnob on January 02, 2012, 07:12:40 amThe test point voltages are referenced to the meter ground, which is TP1. The front-panel common input is also tied to the meter ground.

author: matt09
author_rank: Regular Contributor
timestamp: October 27, 2016, 03:05:35 am
content: Not meaning to drag up a dead topic but I've just spent AGES trying to get this seemingly very simple circuit to work. I had no problem with getting the correct voltage out the regulator but the other board layout is deceptive. It appears very similar so you break the tracks to find that because of different spur off layouts on the pcb things don't join up anymore as they should.Got there in the end..

author: eugenenine
author_rank: Frequent Contributor
timestamp: October 27, 2016, 11:11:21 am
content: I did similar with mine after the second set of batteries died. Since its a simple charger it will wear out the batteries every few years. IIRc I desoldered their regulator and mounted my own 7805 with a jumper wire so it didn't require cutting any traces.

author: matt09
author_rank: Regular Contributor
timestamp: October 27, 2016, 09:52:32 pm
content: I came close to doing the same but my stubbornness prevailed.

author: eugenenine
author_rank: Frequent Contributor
timestamp: October 28, 2016, 12:35:46 am
content: Mine would never work and charge the batteries at the same time. So I'd be in the middle of something and it would die.

author: emptech
author_rank: Regular Contributor
timestamp: December 05, 2016, 07:32:49 pm
content: I purchased my 8050 brand new when it first came out, I think I paid over $500 for it. Through the years, had the same issue, the ni-cads would die,would usually short circuit. I've replaced them from time to time. Looking at the original circuit, I see it is a constant current source, with two settings. What it needs is constant voltage, which your mod does, and current limiting. I see as a constant current source, it is eventually going to cook the batteries.What was so unique with that meter, the low ohms scale.I like to keep old equipment alive too -Jim

author: Bassblaster505
author_rank: Contributor
timestamp: January 07, 2017, 07:10:28 am
content: Quote from: ModemHead on January 02, 2012, 04:25:18 pmI think my board is different than both of yours. U26P1 connects to 4 points and i have no clue what i need to do here. my board is Rev R model 8050A-3001

author: MickM
author_rank: Regular Contributor
timestamp: January 07, 2017, 05:50:32 pm
content: https://www.amazon.com/gp/product/B01N4476AK/ref=oh_aui_search_detailpage?ie=UTF8&th=1They are slightly smaller than stock, part of a paper napkin stops the rattles.They work fine, as a bonus it is now portable, and two spares.Mick M.

author: ModemHead
author_rank: Frequent Contributor
timestamp: January 07, 2017, 06:08:53 pm
content: Pardon my bluntness, but if modding the circuit board presents a challenge, it would be best to solder up a couple of pairs of new NiCd cells, as suggested already. Sub-C, AA, just about anything will allow the meter to operate normally.

author: randalstout
author_rank: Newbie
timestamp: November 02, 2017, 03:34:36 am
content: Wow, thank you so much for this one! I was about to pull my hair out on the issues. Power supply, power supply, power supply...

author: kelchm
author_rank: Regular Contributor
timestamp: January 11, 2018, 09:08:44 pm
content: Can anyone identify the connectors used on the batteries in the 8050A? I'd like to order some new ones for when I replace the batteries in mine.

author: xwarp
author_rank: Frequent Contributor
timestamp: January 12, 2018, 12:37:23 am
content: When I replaced the batteries on mine, I just soldered the wires to the tabs on the cells.

author: Electro Detective
author_rank: Super Contributor
timestamp: January 12, 2018, 02:43:35 am
content: Please excuse the Off Topic question:My 8050A (non battery version) works great at all settings, and agrees with other meters,except when measuring AC 240 volts mains voltage on the 750V AC RangeIt displays a few volts difference compared to handheld 87v, 8060A and other TRMS meters which all closely agree amongst each other.It's not a deal breaker, as a few volts here or there when verifying the mains power is ok, and the 8050A is consistentI'm just wondering whether that particular AC range is out of calibration,or 8050A implements a different measuring system,influence from the high AC bandwidth response,mains/earth/neutral powered influenceor perhaps the 8050A is more on the money with such a measurementor maybe it's tweak time...

author: kelchm
author_rank: Regular Contributor
timestamp: January 12, 2018, 02:46:09 am
content: Quote from: xwarp on January 12, 2018, 12:37:23 amThe connectors on mine are already shot.I'm sure I could come up with something that would work well, but it would be nice to just be able to buy the correct connector.

author: amspire
author_rank: Super Contributor
timestamp: January 12, 2018, 05:52:19 am
content: Quote from: Electro Detective on January 12, 2018, 02:43:35 amWhen you say a few volts, an error of 2.4 volts is still within the accuracy spec for the 8050A's first year. Given all the decades since then, it could now be a little further off. Get the 8050A manual pdf and if you want to tweak the 750V range to make it the same as the other meters, go for it. I seem to remember there are adjustments to the RMS converter - don't touch those. For most settings, the 8050 stays very accurate over time.

author: kelchm
author_rank: Regular Contributor
timestamp: January 16, 2018, 10:22:35 pm
content: Quote from: kelchm on January 11, 2018, 09:08:44 pmTo answer my own question, the connectors are classified as 1.47mm barrel/bullet connectors.I can confirm that both of the following from TE Connectivity work well:60940-1 (Digi-Key Part Number A111354CT-ND)60888-2 (Digi-Key Part Number A100338CT-ND)

author: kelchm
author_rank: Regular Contributor
timestamp: January 19, 2018, 01:18:04 am
content: I began taking a look at one of my 'broken' Fluke 8050A's tonight and was disappointed to find quite a bit of damage. I think this one will be relegated to the parts pile. At least I got a good LCD out of it.My question is wether this damage was caused by the caps leaking their guts or by some foreign substance (water?). I ask because I'm wondering if I should proactively replace all the caps in my working 8050A's.Photos

author: Electro Detective
author_rank: Super Contributor
timestamp: January 19, 2018, 03:19:48 am
content: Open them all up asap, put them side by side for comparison and take PHOTOS,may as well deal with itwhile it's fresh in your mindMine is a mains operated unit (non battery model) and last time I looked about 6 months ago everything looked like new inside, no weird caps, smells, or leakage,everything still in specIt may depend on the board revision as to whether some had leak prone caps, or perhaps the internal batteries spewed out clear stuff,or heat, humidity and moisture issues where the units are parked, or a beer session gone ouch!Same deal with the handheld 8060A, later revisions had better or reputable branded capacitors

author: lowimpedance
author_rank: Super Contributor
timestamp: January 19, 2018, 04:27:02 am
content: Indeed it does look like electrolyte from the nearby cap. Most certainly replace the same caps in your good 8050s as a proactive step.Perhaps the damaged one can be cleaned up and repaired and join the line up again.And now you have got me worried, will go and check my 'crew' out right away.

author: kelchm
author_rank: Regular Contributor
timestamp: January 19, 2018, 01:34:11 pm
content: Quote from: Electro Detective on January 19, 2018, 03:19:48 amWill do!I have five of the 8050As, so it will be interesting to take a look at the differences side by side.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 19, 2018, 01:58:49 pm
content: That one sure knew how to puke up...It is hard to say from photos how bad the corrosion is but you might be able to clean it up worth a try any case before you junk it.If you have same units i would replace that cap on them and maybe recap them fully for peace of mind.

author: kelchm
author_rank: Regular Contributor
timestamp: January 24, 2018, 08:00:56 pm
content: Wanted to share something I started working on last week. I've been fascinated with the various 8050A display mods since before I even owned one. There's something really cool about taking an old, reliable piece of gear and putting your own spin on it by replacing the entire display.I've decided to take it one step further and use a 2.4" display rather than the 2.2" Adafruit display that others have used. It's averysnug fit, and I did have to shave about half a millimeter off the bottom tabs on the panel. It's still the same resolution, but I think the end result is going to look great.Edit: The display in the photo is made by New Haven Display (NHD-2.4-240320CF-CSXN#-F). I really like how solidly built the display is. It even has a metal case/backing which I've never seen on a lcd this small.

author: kelchm
author_rank: Regular Contributor
timestamp: February 07, 2018, 05:10:29 am
content: Anyone have any thoughts on what brand/series of capacitors to use when replacing the capacitors on my 8050A's?I'm considering the Rubycon YXJ series currently since they offer very long life but are not low ESR, which I think would not be desirable in this case.

author: marcuswilson007
author_rank: Newbie
timestamp: February 09, 2018, 05:53:47 am
content: I have 3 8050As and none of them will work withot batteries.When turned off the batteries charge and when turned on they run on the batteries, the batteries do not charge when the meter is operating.I assume that is to reduce the mains noise getting into the meter while measurements are being made.

author: lowimpedance
author_rank: Super Contributor
timestamp: February 09, 2018, 11:25:36 am
content: Quote from: lowimpedance on January 19, 2018, 04:27:02 amJust checked all my 8050's and an 8012 and a 8010.Of the 3 8050's two are mains only , and I found the22 uF/16 V caps were just starting to leak. The 220 and 470 microfarad capsdid not show sign's of leakage. I have not investigated the battery model yet as itcontains many more electrolytic's than the mains version.As for the 8010 and 12 models both are battery versions and use the same caps andI found in both the small 22uF/16 V are also starting corrosion on their pads too.Note that despite the same value they are not of the same series or manufacturer !.So this has been a timely reminder to check old gear with these damn little electro'sotherwise the little bastards will be happily chewing through your favorite gear.Many thanks to kelchm for bringing this to our attention, all be it at the expense of oneOf his "50's" (hopefully still salvageable).BTW interesting to see the display mod up and running, will look cool I'll bet.

author: kelchm
author_rank: Regular Contributor
timestamp: February 14, 2018, 06:08:37 am
content: Quote from: lowimpedance on February 09, 2018, 11:25:36 amHave you begun to pick out replacement caps yet? I’ve been struggling with how to narrow down down what specs I should be looking for beyond the basics.

author: lowimpedance
author_rank: Super Contributor
timestamp: February 15, 2018, 11:53:19 pm
content: Quote from: kelchm on February 14, 2018, 06:08:37 amLooking at the schematic only C21 and 24 could be low ESR types, and the rest could be general purpose electrolytics. No need to over analyze it. Just upsize the voltage rating a little since modernequivalents in the same voltage rating will be quite a bit smaller and the physical mounting may not match the hole spacing.

author: Barrelshifter
author_rank: Newbie
timestamp: May 06, 2019, 02:34:05 pm
content: I want to describe how I modified the 8050A Revision 3001 PCB for using only with AC Power.The rev. 3001 board is different to the board showed here to convert the LM317 from current source to regulator mode (5V).Even the replacement of the LM317 to a LM7805 could not be done directly in the 3001 revision board. This is because of the different layout the pcb has.The easiest way is to remove the LM317, the batteries and their compartments completely. You do not need them anymore.The 7805 needs a small heat sink.It is important, that you place the +5V wire from the 7805 to pinhole 1 AND 2 (bridge). If you miss pin 2, than the meter will not be functional.I mount the 7805 on the place where one of the batteries was installed before.See attached schematic for details.

author: weejag
author_rank: Contributor
timestamp: June 25, 2021, 09:29:52 pm
content: Thank you to Modemhead for posting the best way to modify the 8050A from battery to mains.The conversion can be done with the other board version.I have three of the battery versions (two of which are fixable) that require new LED's and which I wish to convert to mains.The motherboard versions are the 8050A-3001 types so I thought that it might be a help to post pictures of the mod for that particular version.I have carried out the mod and confirm that it works and gives the required voltages.Testing the voltages: test point 1: ground, test point 2: 13v (actually 14), test point 3: 6v, test point 4: -5v, test point 5: -10vThe mod is the same as ModemHead posted:R25 does not require removal. Simply short the pins on the solder side. R26 is replaced with a 150resisitor.The 510resistor is placed on the solder side as shown. Be careful not to short this or the links to anywhere undesirable.

author: WimWalther
author_rank: Regular Contributor
timestamp: September 15, 2023, 07:12:27 am
content: Old topic.. but if you landed here, you might just need to know that the battery-option Fluke 8050A will NOT operate with a bad battery pack - even IF it is connected to the AC mains.If the display just flickers a bit and goes quiet, replace the NiCd batteries, it should fix it.

author: Twinsig
author_rank: Newbie
timestamp: October 08, 2023, 04:03:49 pm
content: Thanks yall (weejag) for this version update..! Needed the help on this version.

author: Twinsig
author_rank: Newbie
timestamp: October 09, 2023, 03:39:12 pm
content: Mod completed. And although my voltage and resistance input tests look good (my fluke 87 for comparison) TP-2 is reading 9.54v as opposed to the stated 13v.IF, anyone is still out there, do you have any experience with this issue?Any suggestions?EDIT: I thought C21 may have been dragging it down, but no. No issues with that & C24. They old ones tested fine but i HAD to replace them with new of course.TP2 remains @ 9.5-ish.I'm going to tap-out on it for now and use it for a while. hopefully it will meet my needs.