Support detect error Fluke 5500A - Page 1
Forum section: electronics / general

author: phucneo
author_rank: Newbie
timestamp: July 10, 2023, 08:56:51 am
content: Hi everybody,i need help,I have auctioned 1 fluke 5500a, when I received it, there was an error,it doesn't seem to be connected to the A9 cpu,Has anyone encountered this error,I'm waiting for the auction company to handle it so I can't teardown it yetdetail error i attach picture bellow, thank for all

author: ddrl46
author_rank: Regular Contributor
timestamp: July 10, 2023, 07:50:05 pm
content: Does the unit not display anything at all when powering up?If so, the unit should display at least "FLUKE CALIBRATOR" on the left display and "STARTING UP" on the right display if the front panel processor is operating, this should happen regardless of the A9 CPU board functioning.Also it might be worth checking that the unit is set to the correct line voltage, you never know.

author: phucneo
author_rank: Newbie
timestamp: July 11, 2023, 03:07:35 am
content: thanks for your support, the device is being set at 110v, i have supplied the correct voltage to the machine, do you think it is faulty somewhere else, maybe there is no power to the A9 board?

author: phucneo
author_rank: Newbie
timestamp: July 11, 2023, 03:18:41 am
content: i got what you mean, it means when it have or no have the A9 board the screen still has to show "FLUKE CALIBRATOR" and "STARTING UP" , so maybe it's losing connection with the front panel processor or this board error . When Once the warranty issue is resolved, I'll try to fix it

author: phucneo
author_rank: Newbie
timestamp: July 12, 2023, 03:01:17 am
content: denied warranty, so last night I took the machine apart, re-plugged all the cards but still not solved the error, I'm thinking it's a faulty A2 encoder board on the front panel. do you think so

author: ddrl46
author_rank: Regular Contributor
timestamp: July 12, 2023, 04:44:30 am
content: Quote from: phucneo on July 12, 2023, 03:01:17 amIf the calibrator does indeed not display anything at all when powered up I would indeed start by checking the A2 front panel encoder board.If all power supplies on this board are present, it would be wise to check activity on the data/address lines of the processor on this board. I have had a unit with a similar fault to your unit which turned out to be caused by a defective processor on the A2 board.It may also be useful to know that the calibrator will refuse to boot any further without being able to communicate with the A2 board.

author: Ugur
author_rank: Regular Contributor
timestamp: July 12, 2023, 05:25:38 am
content: hello guys,Can you help me with a different issue with the Fluke 5500A?The device was not generating DCV. (It gave error message 1004 and 1015) DG444's and U58 LTC1151 Op-amp in the Diagnostic circuit on the A6 board were replaced. Now low voltages are fine but at high voltages it cuts the output. Now it gives the error message (Error 1000 - Sequence failed during diag - DAC330VL). Do you have a comments about it?

author: phucneo
author_rank: Newbie
timestamp: July 12, 2023, 08:11:42 am
content: thank you very much,i check voltage of A2 Board, this board power supply shorted, I'm trying to found out what caused the short circuit, I'll update soon

author: ddrl46
author_rank: Regular Contributor
timestamp: July 12, 2023, 06:09:11 pm
content: Quote from: Ugur on July 12, 2023, 05:25:38 amDo you see any output at all when attempting to source any DC voltage in the 330V and 1kV ranges, both positive and negative? It might also be a good idea to try AC in these ranges.If you have replaced the DG444s in the diagnostics circuitry it might also be wise to check the continuity of the SNS_LO line on the P106 connector (pins A/C 27) to the junction between CR14/CR15. Unfortunately I've experienced a few cases where this trace burns up during a overload event. This can cause some interesting faults.

author: Ugur
author_rank: Regular Contributor
timestamp: July 13, 2023, 05:22:21 am
content: Hello,Thank you for your answer.In the diagnostic test, the high voltage test does not start anyway, I get the error message that I mentioned in my previous message.While testing manually, DC Volt values up to 30V are very good. When the voltage rises, it cannot keep the output value stable and after a while it gives an error and turns off the output. For example, when I get 80V DC output, it oscillates between 74-84V and cuts the output.As you said, there is a problem with ACV outputs.I checked the CR14/15 but I will check its connection to the P106.Yes, this is the first time I've had such an error. It will be a good experience. I will let you know the result.I would be glad if you have any other comments regarding this problem.

author: Ugur
author_rank: Regular Contributor
timestamp: July 13, 2023, 09:43:08 pm
content: Hello,I followed the SNS_LO line, there is no broken line. CR14 and CR15 are in good.Output values up to AC 33V are good, but when I go above 33V, the range changes and turns off the output.Output values up to DC 33V are fine. an upper range also gives the value, but it is not stable. When I increase the voltage a little more, it turns off the output.Do you have a suggestion about this issue?

author: ddrl46
author_rank: Regular Contributor
timestamp: July 15, 2023, 01:13:02 pm
content: Quote from: Ugur on July 13, 2023, 09:43:08 pmIf output values up to 33V AC/DC are correct then at least the main output amplifier on the A8 Voltage board appears to be working as expected, but isolating the fault to a specific section is going to be a bit tricky.For voltages above 33V AC/DC the calibrator makes use of various step-up transformers which are located on the A8 assembly, the specific transformer depends on a few parameters.The big transformer (T3) is used for low frequency ACV (<= 2 kHz if I remember correctly), the smaller potted transformer (T2) is used for high voltage DCV and higher frequency ACV.The primaries of these transformers are driven by the same amplifier used for voltage in the 33V range, also located on the A8 assembly.Trying different AC voltage/frequency combinations might aid in isolating the fault, as well as checking all components on the secondaries of the transformers on this board.I've also had some issues with zener diode VR5 failing on this board, this diode is located in the top left of the board.Certain parts on the A6 assembly are used differently depending on the output range selected, the Fluke 57/LFC service manual has a very detailed theory of operation. This instrument is a bit newer, but a lot of the details of the A6 assembly are similar.You mentioned that the output switches off when going above 33V AC, does it throw an error when this happens? And if so, what error?

author: Ugur
author_rank: Regular Contributor
timestamp: July 15, 2023, 06:41:56 pm
content: Thank you for your answer.I got the ERROR 104 error when I applied a value over AC 33V.I then checked the A8 board. I couldn't detect any suspicious parts. I just doubtedVR6. (P6KE7.5C) I had version 10C and I replaced it with this one.Now if I increase the voltage step by step, it sometimes goes up to 80V and then cuts it to 100V. but it usually cuts over 33V and gives error message 1503. I think the A8 board is hotter than normal. mosfet and regulated coolers get very hot. Regulated voltages are stable.By the way, do you know the part number of the CR51 which is located at the output of T2 on the A8?Actually I am not sure whether A6 or A8 is at fault for this error.

author: ddrl46
author_rank: Regular Contributor
timestamp: July 15, 2023, 08:00:42 pm
content: Quote from: Ugur on July 15, 2023, 06:41:56 pmGetting error 104 (hardware relay trip) does narrow things down somewhat, this fault occurs when the "FAULT" pin on any of the assemblies is pulled to ground.It would be quite useful to know what assembly is triggering this error, here are some places which might be worth looking at:The A6 assembly has a comparator (U50) on the output of U21 which triggers if the output of U21 exceeds +/- 10V.The A8 assembly keeps track of some of the power supplies on it, as well as the balance between the +/- 65V supplies using some comparators.It might also be helpful to remove the other assemblies to make sure they are not involved in any of your issues as well, it is perfectly safe to remove the A7 and A5 assemblies for troubleshooting.

author: Ugur
author_rank: Regular Contributor
timestamp: July 15, 2023, 09:58:18 pm
content: Now I'm pretty sure the problem is caused by the A8. And the defective card gets very hot.I am currently getting Error 399: Fault during DDC330V.I have a working but old version A8 board. With this card, the device works well.I hope I can solve it soon.In the +65V/-65V circuit, the zener is usually faulty, but all looks good on this board.

author: Jetecnet
author_rank: Contributor
timestamp: July 16, 2023, 05:11:55 pm
content: Check R55/56 R63/65 on the A8 board, they often change value or go o/c causing a hardware trip. They are located in a narrow gap between T3 and Q11 . An update is to replace R55 with an 1N4007 diode (cathode towards R56) with a 0.68uF cap across. This, I believe, stops hardware trips at HV and high frequency. The small regulators do run hot on these.

author: Ugur
author_rank: Regular Contributor
timestamp: July 16, 2023, 05:39:10 pm
content: Thank you very much for your response.I checked the R55-56-63-55 and also checked many parts but I couldn't find any defective or suspicious parts.My +65 and -65 voltages are ii and stable.My regulated voltages are -5,+5,-15,+15 all good.But as soon as you start the device, Q16, Q17, Q11, Q14 get very hot.If it does a diagnostic test without waiting for it to warm up completely, it gives a DDC1000 error, but after warming up a bit, I get the DDC330 error.First of all, I need to find the cause of this warming. If I can solve this, actually my problem will be solved.A bug I haven't encountered beforeby the way, all the mosfets and transistors that get hot are solid..

author: Ugur
author_rank: Regular Contributor
timestamp: September 14, 2023, 08:16:23 pm
content: Hello Everyone,I need your supports.I've been dealing with this faulty A8 card for a few days.Q22 mosfet CR51 diode and U18 opamp were defective so I replaced them.Now when I turn on the device I get the same error messages.AC and DC volt outputs are very good up to 33V, but if I switch to the 33V Range level, the output cuts off.I measure very low values for short periods in TP12 and TP13 in the 33V range.I have checked almost all the parts over and over again but I cannot find a faulty part.Something caught my attention, I'm not sure if it's normal or not.All my mosfets and transistors mounted with the heat sink are getting hot.When I measure +65 and -65V values, I see both stable -+64V.However, even if the device's outputs are off, if I write a value at 3.3V range to the device, my +65V value increases to +77V.Is this normal?I will be grateful to anyone who will support me in solving this problem.

author: Ugur
author_rank: Regular Contributor
timestamp: September 14, 2023, 08:41:43 pm
content: A8 board

author: Ugur
author_rank: Regular Contributor
timestamp: September 18, 2023, 07:57:22 pm
content: Hello,I measure 1.75 Kohm between the output of the T3 transformer, that is, the set and reset pins of the K6 relay. Is this normal?

author: ddrl46
author_rank: Regular Contributor
timestamp: September 19, 2023, 04:48:43 pm
content: Quote from: Ugur on September 18, 2023, 07:57:22 pmMy working A8 board measures about 2,1 kOhm between those two points, so not unreasonable. The value between pin 9 of K6 and SCOM (ground plane) is also more or less this same value.Your change in the +65V rail when switching between functions is normal, relay K2 on the A8 board switches a zener in/out of circuit to change the set point of the voltage regulator.What exact error codes do you get when you run a self test? Does it also report a second error if you press a blue softkey?Does the calibrator throw an error when you try to enable the output above 33V?

author: Ugur
author_rank: Regular Contributor
timestamp: September 19, 2023, 05:36:04 pm
content: Hello,I appreciate your support, thank you very much.When I removed the transformer and checked it, I could not measure any ohm values.When it goes to the high voltage test step during the self-test, it gives an error message before completing the first test. Err104 DAC330VL and Err 1000 error messages.It produces AC and DC values up to 33V.If I set it to an AC value above 33V, for example 35V, I read a value of 300-500mV on the outputs and it gives a hardware error in a short time and turns off the outputs.If I set it to a DC value above 33V, it produces a little error, but when I increase the voltage step by step, after a while I get the same error message and Q22 - CR51 breaks.It produces all other values.

author: ddrl46
author_rank: Regular Contributor
timestamp: September 19, 2023, 07:02:55 pm
content: Quote from: Ugur on September 19, 2023, 05:36:04 pmJust checking, but you are using the board of which you shared a picture above in a 5500A? If so, that board is designed for the 5520A / 5522A series and is not compatible with the 5500A as far as I know.

author: Ugur
author_rank: Regular Contributor
timestamp: September 20, 2023, 06:18:14 am
content: OMG. Yes, this information was written on the label on the card, but I thought it might be compatible. Are you sure about this?For example, I know that the A4 card is compatible with 5500A and 5502A.

author: ddrl46
author_rank: Regular Contributor
timestamp: September 20, 2023, 03:50:24 pm
content: Quote from: Ugur on September 20, 2023, 06:18:14 amI have never personally tried fitting a 5520A A8 voltage board inside of a 5500A or the other way around, so I can not definitely say they are 100% incompatible but I do have a strong suspicion that it is. All of the other calibrator boards, besides the A4 scope option, are quite a bit different between the 5500A and 5520A.The A8 board is somewhat similar but includes an additional transformer (above T2) and associated switching circuitry for the higher frequency AC that the 5520A is capable of. It may also be possible that the pin-out of the connector on the left side might be slightly different.It might be wise to check the connections of the relay drivers to the associated relays and shift registers using the 5500A schematic, it might be possible that this digital logic is not exactly the same between the two boards.

author: Ugur
author_rank: Regular Contributor
timestamp: September 21, 2023, 05:29:05 am
content: Thank you very much for your comment.I measured the primary side of the T3 side as open circuit, so this is definitely defective! First I will have this transformer repaired and then I will test it.I hope the problem is solved and the device works with this card.Because this card was already installed in this device before it malfunctioned. I will let you know the result.

author: Ugur
author_rank: Regular Contributor
timestamp: September 27, 2023, 06:22:51 am
content: Hello my friend,I had the T3 transformer repaired and tried the device again, but my problem continues. This error really made me tired. If I can't find a solution after looking for a few more days, I will give up.As soon as I turn the device on, my -15, +15, 5V regulate ICs and Q16, Q17 MOSFETs get hot. (Q12, Q14 transcitors heat up a little slower).Although there are no short circuits and all my regulated voltages are stable, I don't understand why they are getting hot.I removed U1 and when I turned the device on, my mosfets and transistors were cold, but my regulate integrated circuits still got hotter than normal.By the way, I compared it with the 5500A A8 card, yes there are differences, but I saw that the pin sockets were the same at least up to the point I checked, at least it shouldn't cause it to heat up like this.I think the 5520A A8 card can work with 5500A.Because this card was inserted before the device broke.

author: ddrl46
author_rank: Regular Contributor
timestamp: September 27, 2023, 07:11:00 pm
content: Quote from: Ugur on September 27, 2023, 06:22:51 amIt might be worthwhile to remove all cards from the calibrator besides the A6 and A8 assembly in order to make sure the fault is isolated to this assembly. The calibrator will happily provide DCV and ACV functions in this configuration.When you say your regulators are getting hot, how hot are they getting? I've had a case where one of the 15V regulators was faulty which only showed up after a while or only in certain instrument configurations. This was due to them using two regulators in parallel, and since once was faulty the other had to take all the load.

author: Ugur
author_rank: Regular Contributor
timestamp: September 28, 2023, 10:51:30 am
content: When I previously inserted another working A8 card into the device, it worked fine, so I think the problem is not caused by the other cards, but no problem, I can remove them.I didn't measure the temperature, but it gets hot enough to burn my hand. The estimate may be 70-80°C. and reaches this temperature in a very short time.I changed the 7915 integrated circuit for -15V, but the result did not change.I had checked the parallel connected regulator for +15V, but the new onesI will replace it with . I will also replace the bridge diode with a new one.But I don't understand why my mosfets and transistors are getting hot.When I remove U1, it does not heat up. When I followed that circuit, I could not find a faulty part.When I apply a value above AC 33V, the value slowly rises to approximately 400mV in TP12, then it gives error 1503 and turns off the output.At the same time, TP13 also rises to 4-5 V level.The voltages I measured in TP12 and TP13 at values up to 33V are very good and stable.Finally, T3's A6 and B1 pins go to the 8th pin of K5, is that correct? Also depends on Q18.Because I measured an open circuit on the board.

author: Ugur
author_rank: Regular Contributor
timestamp: September 29, 2023, 05:56:01 am
content: I removed the cards except A6 and A8, but the result did not change.As you said, one of the parallel connected +15V regulated integrated circuits is faulty. When I checked it alone, I measured an unstable voltage between 16-19 V. I replaced both of these and also replaced the bridge diode.Unfortunately, the result did not change again.

author: Brandy
author_rank: Newbie
timestamp: February 19, 2025, 10:39:21 am
content: Hi all,check (and probably replace) U4 and U13 on the A8 board.Both are "LF356N" ICs.If one or both (I can't remember, sorry for that) ist faulty, you get "tripped to standby" at voltages from 33V and above, and also Error 104, 399 and 1000 during self test.I hope this helps a bit ;-)Brandy