Teardown : HP 4263B LCR Bridge meter (and repair) - Page 1
Forum section: electronics / repair

author: TiN
author_rank: Super Contributor
timestamp: January 07, 2014, 09:46:45 am
content: Ok, time to start new restoration thread, this time HP/Agilent 4263B LCR meter. Yes, it's not Keithley, as some people already wonderingabout Keithley graveyard in here, and reliability of their productsAny owners of 4263B, which don't care warranty and can open up their meter (just 4 screws on sides and cover off) and take photo to give me a handin repairs?I'd like to know value or photo of four thru-hole resistors near J101 (A output). They are burnt on 4263B i received today badly, so cannot read value.Attached photo of them. Also one burnt SMD resistor from pin 2 of U182, D5210G IC.Also photo of SMD side on two mosfet/transistor module U107 would be helpful (some parts blown there too) but that need removal of front panel (uncrew 6 screws and disconnect frontterminals)4263B Service manual does not contain parts list, nor schematics to help on this matter.Units still power on, and gives PASS on self-test, but i doubt it works fine with these damages....Teardown coming...So far total visible damages:4 x 1/2W resistors (need value for them)Broken in halftranzorb Z6010Burnt 1206 on main pcb (100 ohm?)And on secondary module with pair of PNP/NPN bulged SOT23 with code Y23 (second module have same layout and same Y23) and bunch of 1206 resistors..As usual - handle tasks viamy redmine tracker.Thanks!

author: TiN
author_rank: Super Contributor
timestamp: January 10, 2014, 05:56:43 pm
content: Noone have 4263B ?

author: TiN
author_rank: Super Contributor
timestamp: January 19, 2014, 06:12:35 pm
content: Seem it's way to go good old way, if want something done - do it by youselfWill try some usual "try put some parts and see what happens" way later.For now teardown, as whole internet don't have a single hi-res photo of 4263B internals...So here we goes, all photos click-able for hi-res.Front panelBack I/OUnit is not deep, but wider than usual Keithley/HP bench meters, so it will not match in rack as for sizeRemove cover by two screws from rear:Bird's viewDisassembly pretty simple and user friendly. All can be done in few minutes. Well thought design layout.Input BNC connectors.LCD is standard 40x2 char type, with very well known 44780 controller. Maybe later I'll change LCD to something with better contrast, if repair will be successful.Protection on inputs?Mains protection and filters.Unit low voltage power supply in it's cage. Two 22000uF 25V KMH capacitors and lot of small 22uF 50V electrolytes.Here goes digital board, mounted on standoffs above signal acquisition bottom board. MC68HC000FN10 CPU, two Sony branded CXK581000AM 70ns SRAMs, Xicor X28C64 ROM, AM27C2048 UV ROM with firmware (04263-85041 on my unit) and some big National Semi S9652AB SCX6B65AHI ASIC, and bunch of 7400 series logic and AMD-branded PALs around.No batteries to store cal/configuration constants or NVRAM, only supercap there. So this unit pretty safe from dying from dead batteries, like some other gearSome sections done with PCB-PCB modules, one of which near standoff had burnt resistors and SOT-23 resistor.It's similar to other presumably alive module, so should be not very hard to find out what it does.Good module:It have PNP and NPN with small heatsinks on another side.Input terminals protection and switching. Probably some stuff is borked here...I already put some resistors to check basic functions, but it's not working right, readings sometimes, all over the joint often, sometimes seem ok.. Need debuggingAnalog/switching/measurement components

author: TiN
author_rank: Super Contributor
timestamp: March 04, 2014, 07:48:19 am
content: Got back to 4263B repair project...Made a schematics for little modules on 4263B front end board.Some kind of half-bridge with pair of PNP/NPN.SOT-23 probably BJTs, need to find out what part are they to replace on faulty module.Faulty module had burnt 51 ohm resistors, 2.2ohm between power BJT's and "Y23" SOT23.

author: ve7xen
author_rank: Super Contributor
timestamp: March 04, 2014, 09:25:14 am
content: I think the transistors are 2SC3734 / 2SC1461. Might be hard to find these days, and mind the gain binning.Nice looking instrument, I look forward to seeing it in operation

author: TiN
author_rank: Super Contributor
timestamp: March 04, 2014, 10:02:21 am
content: Great info.I'll just buy modern replacement with similar parameters.

author: TiN
author_rank: Super Contributor
timestamp: March 04, 2014, 05:55:57 pm
content: Replaced small PNP with similar part and bodged 1206 resistors.Soldered 2 x 50ohm resistors instead of burnt ones (wild guess on resistance value, lol).Removed blown transzorb (will install it later, don't have replacement atm).LCR meter now able to do some measurements, seem pretty ok.Self-test pass ok as well.

author: Zucca
author_rank: Unknown
timestamp: March 04, 2014, 06:27:36 pm
content: Kudos TiN!That HP 4263B was on my watching list for about 2-3 weeks, and I have to admit I would have been not able to repair it. The seller told me just the 4 resistor were broken, go figure.I got at the end a DE-5000 (for my first LCR Meter, it is good enough).I am happy that it ended to someone at the EEVBlog, still very surprised none here had one to compare/post some picture.I think you made a good deal for that price.Good Luck and keep posted on what is going on.

author: VK5RC
author_rank: Unknown
timestamp: March 05, 2014, 01:33:35 am
content: I am sorry I can't help, have you tried the yahoo hp/Agilent group?It sounds as though you are doing well by yourself. When you do fix it, I would post there as well, regards Rob

author: TiN
author_rank: Super Contributor
timestamp: April 30, 2014, 01:32:17 pm
content: Okay, some useless update/modification. I like negative LCDs more, so replaced original 40 x 2 for a blue negative.Because it's HD44780 compatible interface, change is plain simple.Before, original display is upper one with cables, new is on bottom.Front faceDesolder ribbon cable for interface from original LCDCable soldered in place. Unconnected pin 15 and pin 16 are just backlight. LED Backlight is connected via separate cable, which is about to be soldered...New negative LCD ready for installation...Needed to update contrast setting resistor (Original 1.0kOhm, new is 2.0kOhm) and increase current for LED backlight by adding few 1R's in series with 10R's near J5 connector on digital board.And final result:Now unit is assembled and permanently joined homelab setup.

author: Zucca
author_rank: Unknown
timestamp: April 30, 2014, 02:00:22 pm
content: Extremely cool TiN, I liked it a lot.One day I hope to hack like you some gear.There is always so much to learn in this Blog...

author: SeanB
author_rank: Super Contributor
timestamp: April 30, 2014, 07:13:09 pm
content: On a lot of those displays the front polariser is a separate item, so you can take it out and flip it around to reverse the LCD. Either turn it 180 degrees or flip front to back and check.

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: June 09, 2014, 02:00:00 am
content: What's the difference between the 4263a and b?

author: free_electron
author_rank: Super Contributor
timestamp: June 09, 2014, 06:02:23 am
content: Proceoor board and display. A uses hp proprietary starbursts like in the 3488 and 6624 supplies. No backlight. When they stopped making those they introduced the b version.The motherboard is the same. Only the cpu card is different (and the software of course)

author: Sailor
author_rank: Regular Contributor
timestamp: June 09, 2014, 07:25:06 am
content: @ TiNI PM'd you a while ago TiN, did you receive it?Regards, Sailor

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 04, 2017, 09:47:41 pm
content: Quote from: SeanB on April 30, 2014, 07:13:09 pm90 degrees, I think. So you need a new polarizer.

author: MiDi
author_rank: Frequent Contributor
timestamp: October 12, 2020, 05:17:29 pm
content: Got a unit with OPT 001 & 002 from 2012 in mint condition, unfortunately with Error E-313: Calibration memory.After a couple of restarts it went through POST without error - so there was hope for recovery of cal rom saving $$$ for full calibration/adjustment.Unit cannot be operated with POST error - unless switching it to ignore POST errors (service manual p. 59).Next step was to take backup of cal eeprom A2U1 X28HC64 (X28C64 on other units spotted).Verification showed several errors - wear out or data retention time expired?Comparison of 20 backups showed at least 12 wobbly bits, but luckily only in unused areas with FF - hence spotting the correct values was easy task.Only one of those backups was correct, it was reflashed and several verifications were successful.Seems this guy not only forgot part of its data, but also his datasheet which states 100 years data retentionSidenote: the programmer needs to handle the software write protection - I used TL866-II+ with Xicor X28C64 template (after failing with AT28C64 - which lacks WP).Now unit powers up without errors, several self tests did not show any error - that was an easy fixAnyway it seems to be a good idea to get a replacement for this forgetful ic, only awailable compatible PDIP-28 as a new part seems to beAT28C64B.It states only 10 years data retention in the datasheet, hopefully this is worst case with margin and better than 8 years of currently installed one.Cal rom for this unit attached for reference.xDevs repository has latest firmware 1.06 and several cal rom backups.As TiNs pictures seem to have vanished, here the link to the article on xDevs.Part of performance verification was successful - as far as I could get with my equipment.PS: Someone in EU who would lend me cal-kit?HPAK equipment (or equivalent) needed for cal:Standard Capacitor Set 16380AStandard Capacitor Set 16380C100m Standard Resistor 42033A1100k Standard Resistor 42039A1OPEN Termination 42090A2SHORT Termination 42091A21m, 2m, 4m Test Leads kit

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: October 12, 2020, 08:48:08 pm
content: haha, extra cookie for the cool cal stickerany idea what it reads?

author: MiDi
author_rank: Frequent Contributor
timestamp: October 13, 2020, 09:45:41 am
content: Unit came from Slovakia, but seems Cal-Sticker is hungarian."Év Következő Felülvizsgálata ideje Hónap" translates to "Next review time Year Month".I guess that means next cal due 12 2019

author: MiDi
author_rank: Frequent Contributor
timestamp: November 16, 2020, 10:36:12 pm
content: Replaced forgetful cal rom A2U1 X28HC64 with AT28C64B without problems.As the keys had a sloppy response the front panel was taken off.The silicone key pad was removed and cleaned carefully with warm water and soap, the counterpart with pcb cleaner.As the front panel was off anyway, I decided to swap the LCD for a black/white one.After setting the contrast with a 1kΩ and adding a current limiting resistor for LED backlight everything was put together again.Keys are now responsive and as new, the display is pleasant with good contrast, but viewing angle could be a touch better.

author: johnbaker26
author_rank: Contributor
timestamp: October 08, 2024, 03:48:10 pm
content: Thanks for this thread it helped me a lot. I picked up a 4263B recently for 250 dollars. Couldn't stand that VCR looking green LCD. Upgraded it with an OLED fromhttps://m.alibaba.com/x/16BM55?ck=pdpAnd it looks quite nice. Did have to Dremel a bit to get it to sit correctly tight against the front. Also moved the original connector around to get back for the same reason. Which requires you to remove the plastic pin holder and solder each wire individually but no big deal.

author: RikV
author_rank: Regular Contributor
timestamp: December 10, 2024, 10:30:45 pm
content: Anyone has a hint where to find the SERVICE manual for the 4263B?Also, is there somemone who can tell if the error20: A1 board test failed and error11: ADC failure (at boot-up)are repairable errors or are they caused by a defective ASIC? firmware is v1.06.

author: picburner
author_rank: Frequent Contributor
timestamp: December 11, 2024, 04:29:10 am
content: The service manual is attached, however it is not very useful in case of errors, because the solution it proposes is to change the various offending boards.

author: RikV
author_rank: Regular Contributor
timestamp: December 11, 2024, 04:52:03 pm
content: Picburner, in your (supposed) experience with the instrument, would it be possible to do any significant repairs to the device? I suppose most, if not all, complex functionality is integrated in the ASICs? So, if no donor device is available, is it worht to buy?

author: Aheld
author_rank: Regular Contributor
timestamp: December 11, 2024, 05:54:42 pm
content: Hi Forum,I have a HP 4338B Miliohm meter, which looks similar to this HP4263B LCR.Do you think it would be possible to upgrade the miliohm meter into LCR meter?Br.Axel

author: picburner
author_rank: Frequent Contributor
timestamp: December 11, 2024, 05:57:37 pm
content: @ RikVDo you have a device that has failed or do you want to buy a failed device to try to repair it?Failures in the analog section are usually repairable but if the failure is a custom component in the digital section, as you have already understood, then the problem is serious, solvable only by replacement from a donor instrument.Also, due to the too synthetic documentation, it would be necessary to have a second working instrument to speed up the discovery of the failed part.In my 4363B I only replaced some electrolytic capacitors and upgraded to opt. 001 and 002, so I did not do too complicated repairs.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 11, 2024, 06:07:46 pm
content: Quote from: Aheld on December 11, 2024, 05:54:42 pmsee here the video,i would say not possible, not the same internals

author: Aheld
author_rank: Regular Contributor
timestamp: December 11, 2024, 09:11:40 pm
content: Thank you,I didn't was aware of this nice video documentation!Br.Axel

author: RikV
author_rank: Regular Contributor
timestamp: December 13, 2024, 08:26:57 pm
content: These are fundamentally different instruments. They originate from the same "style" made by HP&Co, meaning they have many metalware and hardware parts in common and thus essentially reduce the BOM of HP's factories and reduce engineering cost. But functionally they are completely different. I guess that -eventually apart from the display/keyboard and power supply- they have nothing in common.