Fluke 8500A, 8502A(T), 8505A, 8506A modules - Page 1
Forum section: electronics / testgear

author: m k
author_rank: Super Contributor
timestamp: November 26, 2021, 09:07:07 am
content: Included list has partnumbers combined from few manuals and some pictures.It even includes the famously missing option -04.If there is a mfg number it's from manual.If mfg number is present but Fluke stock number is missing they are the same.If there is no option ID then it's from picture.Rest are eighter way.Some variable module placements.8506Thermal trueRMS MultimeterInstruction ManualP/N 638858MARCH 1983page 8-8Slot ADC Signal Conditioner8505ADIGITAL MULTIMETERInstruction ManualP/N 638841March 1983 Rev.2 2/91page 8-8Slot CDC Signal Conditionerhere and xDevs have pictures whereD DC Signal ConditionerC AC/DC Converter (RMS)B Ohms ConverterA Current ShuntsDisclaimerIncluded list is a totally new intervention.And so can be taken as a clean second guess.E,Cal MemoryAddressingID A_Cal7 - 76 - 65 - 14 - 23 - 32 - 41 - 50 - 0Read is actually not Write so Address and Enable will read and both will create their own ACK.E2,Code:Input-----------------| | | || Ohms Currents || \ / \ || RT1 RT3 |\ / \ \ /DC--- ----AC\ /----------|RT6|Active Filter|RT5|Fast RR A/DFor 8506A the Thermal TRMS is not mandatory per se, but among ACs it is.So you can leave it off and the machine is fine with simultaneous Ohms and Currents.In case you hack 8505A to be 8506A remember button placings.U18A0 - A11A1 - A12A2 - A13A3 - A14A4 - memory cycle or notO1 - U24O2 - U23O3 - U22O4 - U20Code:0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 11110000 1110 E 1110 E 1110 E 1110 E 1101 D 1101 D 1101 D 1101 D 1011 B 0111 7 1111 F 1111 F 1111 F 1111 F 1111 F 1111 F.......1000 1110 E 1110 E 1110 E 1110 E 1110 E 1110 E 1110 E 1110 E 1101 D 1101 D 1101 D 1101 D 1011 B 0111 7 1111 F 1111 F.......Rest are F, so the whole DM74s287/N82s129 is programmed and can't be reused.(TBP14s10N on schematics)Since A13 is directly wired to U24 and 2nd set has double area for U24 one can guess that they have had some bigger ROM chip thoughts.U18 ROM can be replaced with 74159 and 4 pull up resistors.original A4 to _G1 and _G2with pull up0-3 outputs to U244-7 outputs to U23output 8 to U22output 9 to U2027256 ROM is a drop in replacement for 2764.Then U23 can be left out, but changing jumper W3 wont work since RAM location changes.Combining and doubling U24 and U23 is fine but U18 content must be changed.Rewiring A13 and lifting chip leg wont do either since _CS is not serviced.Replacing U18 with 74159 will do, then its outputs 0-7 are combined to socket's _CS.If replacement 74159 is used then remaining empty ROM socket can be used for extra software.Then A-F outputs are combined to empty socket _CS and extra ROM space is available.In case of extra software keep in mind that it's of course also possible that original software is testing that originally unused address space.

author: m k
author_rank: Super Contributor
timestamp: November 26, 2021, 07:06:52 pm
content: One Front/Rear more for 8506A and corrected A11 stock number typo.Can't find a reason why I thought elsewhere that DC Signal Conditioner was universaly interchangeable.Early and late part numbers are different.E,ods to xls

author: Martian Tech
author_rank: Regular Contributor
timestamp: November 27, 2021, 04:27:35 am
content: For reference, here's the inside of an 8500A.

author: m k
author_rank: Super Contributor
timestamp: November 27, 2021, 12:44:04 pm
content: IEEE-488 is not last, how the external connection happens?

author: m k
author_rank: Super Contributor
timestamp: November 27, 2021, 12:47:58 pm
content: One 8500A manual added.Controller is one module but two parts.Maybe CPU and ROMs were so expensive.My guess for dual PCB controller is 8502A/AT and its extra needs.Though the manual has only single module controller listed.8502A/AT(manual p/n 577049)includes calibration memory(-04) as a standard feature.Same with all A22 to A30 modules.Operates with 400Hz mains.Error A is illegal Thermal TRMS controller switches selectedError E is more than one Thermal TRMS controllers installedBootHI-3.0.0C2454A 8Cal Memory module has a battery and 2 RAM chips.(429860 P5101L and 408757 P5101L-3)8502A(manual p/n 471466 rev 1 7/81)Figure 8-7A6 Controller PCB Assembly - Single PCB versionCPU and ROMs are blank, no component numbers, chip rectangles are present.2 last of 6 RAM chips are completely missing, empty space in picture.Figure 8-8A6A1 Controller PCB Assembly - Double PCB version1 ROM socket, no chips.All ROMs are labeled as not used.4th is also labeled as double PCB version interconnection.2 last of 6 RAM chips are labeled as not used.A6A2 Controller PCB Assembly - Double PCB version5 of 6 ROM chips are without sockets.6th is missing but socket is present, location like 3rd in A6A1.Schematics has no address lines for that 6th ROM.BTW, I have a strong feeling that I've seen a picture of Cal Memory module recently.Can be a fake memory but if that lateral top edge battery is black and those two panduits are still strapped then it can be somebody's published but unknown feature.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 27, 2021, 05:02:49 pm
content: For the controller module there could be different versions: with more modern parts a single ROM or RAM chip could replace 2 or 4 chips. So the newer version may get the same function with less parts.Using 2 PCBs for the controller would be just the space needed with multiple chips for the RAM and ROM.

author: m k
author_rank: Super Contributor
timestamp: November 27, 2021, 08:34:10 pm
content: 8500A ROMs have Fluke numbers only, 4 pieces, CPU is named TMS8080.8502A has 6x 2716 for double board and 3 ROMs and 1 PROM for single board.Cal Memory then has 2 static RAMs with different part numbers.Sure data inside is finally different but how it is maintained.Maybe you were able to order them but delivery was onsite factory only.Or maybe they knew or visioned that EEPROMs were coming.E,completely forgot those famous SRAM + battery chips.

author: m k
author_rank: Super Contributor
timestamp: November 28, 2021, 05:31:41 pm
content: Cal Memory Module

author: Martian Tech
author_rank: Regular Contributor
timestamp: November 29, 2021, 03:29:03 am
content: Quote from: m k on November 27, 2021, 12:44:04 pmThis is from the 8502A manual, but presumably the same for the 8500A

author: m k
author_rank: Super Contributor
timestamp: November 29, 2021, 11:28:31 am
content: Yes, it's not illegally placed but its usage is a bit difficult from there.If it is not just stored there.Another thing from the list, controller's preferred location seems to be bus termination something.

author: m k
author_rank: Super Contributor
timestamp: December 01, 2021, 07:58:33 pm
content: Bus Interconnect in slot K.

author: m k
author_rank: Super Contributor
timestamp: December 09, 2022, 05:21:17 pm
content: Some module addresses added to modules file.IC is inverted in software and msb is included.

author: m k
author_rank: Super Contributor
timestamp: December 18, 2022, 05:52:01 pm
content: Sorry about the inconvenience.OP's original ROM set 503/604 is invalid, has this been up already, can't really remember.(still there for a moment and for the reference)I have 3 sets on the table right now, 502/603 and 503/604 are original chips and 506/607 is self made, all are working copies.My MiniPRO something can't read said 503/604 U24 chip, U23 is unknown.I also just successfully copied 502/603 set with that same MiniPRO, destination being M28C64A, using AM28C64A MiniPRO type, and successfully used said 503/604 originals, and newly copied 502/603 EEPROM set, on the same controller.So some weak bits then, but unfortunately only for the MiniPRO.Disassembled software below is from 506/607 U24.All versions seem to be starting equally, first jump address location differs.That jump address also always includes, sooner or later, that delay of 0x452C cycles.The faulty 503/604 U24 copy has at least one error, 18 in place of 1B DCX DE.Somewhere is also a sort of aCRCchecksum,but can't remember where.It's in the middle of the code and it is included to the count.Code:0x0000 26 C0 MVI H, 0xC00x0002 36 FF MVI (HL), 0xFF0x0004 C3 DB 02 JMP 0x02DB0x02DB 3E FF MVI A, 0xFF0x02DD 26 E0 MVI H, 0xE00x02DF 77 MOV (HL), A0x02E0 24 INR H0x02E1 C2 DF 02 JNZ 0x02DF0x02E4 11 2C 45 LXI DE, 0x452C0x02E7 7A MOV A, D0x02E8 B3 ORA E0x02E9 1B DCX DE0x02EA C2 E7 02 JNZ 0x02E70x02ED C3 38 00 JMP 0x0038E,Changed a nuance.E2,ChecksumCode:0x009C 11 00 40 LXI DE, 0x40000x009F 26 42 MVI H, 0x420x00A1 AF XRA A0x00A2 12 STAX (DE)0x00A3 1C INR E0x00A4 C2 A2 00 JNZ 0x00A20x00A7 14 INR D0x00A8 7A MOV A, D0x00A9 BC CMP H0x00AA C2 A1 00 JNZ 0x00A10x00AD 0E 95 MVI C, 0x95 ; Checksum zeroing value?0x00AF 79 MOV A, C0x00B0 B7 ORA A0x00B1 C4 13 22 CNZ 0x2213 ; clear (DE) count C...; Checksum0x0180 21 00 00 LXI HL, 0x00000x0183 AF XRA A0x0184 86 ADD (HL)0x0185 2C INR L0x0186 C2 84 01 JNZ 0x01840x0189 47 MOV B, A0x018A 24 INR H0x018B 3E 40 MVI A, 0x400x018D BC CMP H0x018E 78 MOV A, B0x018F C2 84 01 JNZ 0x01840x0192 F5 PUSH AF ; 0x0C8C 3A 00 41 LDA (0x4100)0x0193 F3 DI ; 0x0C8F E6 70 ANI 0x700x0194 CD 8C 0C CALL 0x0C8C ; 0x0C91 C9 RET0x0197 C4 5F 15 CNZ 0x155F ; ext. I/O reset0x019A F1 POP AF ; 0x02F0 F5 PUSH AF0x019B B7 ORA A ; test result 0x02F1 3E F0 MVI A, 0xF00x019C 0E 08 MVI C, 0x08 ; 0x02F3 CD 85 05 CALL 0x05850x019E FB EI ; 0x02F6 F1 POP AF0x019F C4 B8 02 CNZ 0x02B8 ; Error 0x02F7 3D DCR A0x01A2 3E 02 MVI A, 0x02 ; 0x02F8 C2 F0 02 JNZ 0x02F00x01A4 CD F0 02 CALL 0x02F0 ; wait 0x02FB C9 RET0x01A7 CD 83 06 CALL 0x0683 ; show module test results

author: m k
author_rank: Super Contributor
timestamp: December 31, 2022, 05:56:35 am
content: 503/604 software is now different.CRCChecksum is zero and the set will boot and start measuring.Filename is a bit different since its reliability is wavering.AnotherCRCchecksum zeroing location can be 0x0007.Before the last version the value of that location is always different.

author: m k
author_rank: Super Contributor
timestamp: February 03, 2023, 03:35:19 pm
content: Backplanefront sidecard edge connector is generally,(based on mechanical 0.1 mm caliper and less than perfect vision)(but printed and verified)1.5" spacing and 2mm wide contacts.Front side slot is 20 center based regulars,then 8 thirds to next center and 2 regulars,then triple wide contact as 2 regulars and their gap,then 5 thirds to next center from 2nd regular of triple wide and 2 regulars,then one regular missing electrical parts.So 1.27 mm spacing can reach all centers but backplane connector is dual finger, so not a good match with PCI edge.E,PCBs are not tested and female connector series is EDAC 379 etc.