[SOLVED] DS1052E Relays not switching input PSW -12v rail only 9.71v DC - Page 1
Forum section: electronics / testgear

author: taylorit
author_rank: Newbie
timestamp: October 28, 2021, 10:41:44 pm
content: Hi Guys,Just wondering if someone could help out with my Rigol DS1052E. None of the inputs work, if I inject signal up stream to Relay #1C or Relay #2C (that then I can see the signal shown on the screen. When changing inputs AC/DC/GND or scale no relays click. PSW voltages are ok apart from the Pin 9 -12v DC. This is only outputing 9.71vdc. I assume this is one of the main supply rails, I have also tested the L7905 it is outputing -5v but thinking it is a -12V issue.? i have checked the 100uf and 330uf caps but can't figure why this rail has dropped in voltage, could it be the MUR460 diode that is faulty.? I'm referencing to the diagrams provided at -http://rigol.codenaschen.de/index.php/SchematicsI have also tested pin 16 on each 74HA595 and they both have +5v.Any help please :-)

author: WattsThat
author_rank: Frequent Contributor
timestamp: October 28, 2021, 11:20:35 pm
content: Did you do a diode check if the MUR460? Start there. Should be 0.7 volts drop. If it checks okay, do you have another scope? If so, measure the ac ripple level on the -12 supply. If no scope, use a meter and measure using the ac range. AC Ripple should be very low (would expect less than 100mv) but that will depend upon the current draw which I have no idea of what it should be. Perhaps another poster might know what the ripple and or current draw actual values.

author: taylorit
author_rank: Newbie
timestamp: October 28, 2021, 11:54:33 pm
content: Thanks for your message. I don't have another scope but tested using AC range, showing 35mVAC on DC -12 rail. I also pulled the MUR460 from the cct and diode tested, open oneway and 0.440v the other. Should the junction be more like 0.7v .? perhaps the diode not happy.? Thanks

author: tautech
author_rank: Super Contributor
timestamp: October 29, 2021, 12:00:39 am
content: Quote from: taylorit on October 28, 2021, 11:54:33 pmCertainly not in spec.https://www.onsemi.com/pdf/datasheet/mur420-d.pdf

author: taylorit
author_rank: Newbie
timestamp: October 29, 2021, 12:07:04 am
content: OK, I'll start with replacing that. Hoping that the dip in voltage is causing the analogue control for relay issue.

author: WattsThat
author_rank: Frequent Contributor
timestamp: October 29, 2021, 04:22:30 am
content: That diode is fine. The forward voltage drop is spec’ed only under load so the 0.7 volts was a guess, based on the description. The -7v level suggests the supply is overloaded, cannot be sure without a current spec which is missing from the schematic, that’s a real shame.I don’t see -12v used anywhere on the schematic nor is the 79L05 shown. That doesn’t help with troubleshooting.Have a decent 12 volt supply? That will require isolation of the -12 which might be as easy as popping a wire out of a connector, I don’t know. Power it externally, see if scope front end works. If so, measure the required current. Resistively load the scope supply to that current and see what happens.

author: taylorit
author_rank: Newbie
timestamp: October 31, 2021, 08:19:07 pm
content: Hi, off the back of the other advise I ordered some replacement diodes. So bit of a shame.. oh well. I have a cheaper supply that only supply upto 40v @ 3A. I had already tried powering up the -12 side via external supply but it kept over currenting and I'm not 100% the PS I have actually delivers 3A (lol). Even when the scope PSU is not connected to the scope the -12 rail at the 9.7v area, So bit stuck now... the other thing is my meter only supports CAP testing up to 40uf, but none of the caps on the PSU look bulged, but could they be failing perhaps.

author: WattsThat
author_rank: Frequent Contributor
timestamp: October 31, 2021, 09:10:27 pm
content: The -12 volt supply requirements are likely far less than 100 millamps, it appears to be just some op amp supplies. If a 3 amp supply is into over current, you’re doing something seriously wrong, like reverse polarity or not disconnecting the supply under investigation.I think you said somewhere the -12V ripple was 35 millivolts, if that’s the case, the caps are fine as well.I think it’s time to step back, reset your thinking and start again. You’re missing something. We only know what you tell us and so far, things are not making sense.

author: WattsThat
author_rank: Frequent Contributor
timestamp: October 31, 2021, 09:12:45 pm
content: As an afterthought, what does the -12 v supply power to ? I don’t see anything on the schematic. Have you traced it out to know what it is connected to?

author: taylorit
author_rank: Newbie
timestamp: October 31, 2021, 11:30:55 pm
content: I have replaced the MUR460 diode as they just arrived anyway, and no difference to output voltage. When I lift the wire from the plug on the -12v the scope doesn't run up. The fan also stops etc.. The L7905 neg 5v reg also is powered by the -12 rail. I have read somewhere the -12v powers the analogue part of the circuit, hence focusing on the dip in voltage. I attached a couple of pics showing PSU and analogue part of cct. At a bit of a loss now, unless the -12v provided on the hand drawn diagrams is incorrect but this building a supply with -9.6v it odd.?

author: AVGresponding
author_rank: Super Contributor
timestamp: November 01, 2021, 06:15:46 am
content: If the -12VDC reg is only kicking out -9.7VDC then for sure it's being overloaded, most likely by a failing tant/electrolytic.Out of curiosity and thoroughness, what's the input voltage measure on that 7912?EDIT: Just looked through the drawings and can now see the -12V rail is unregulated. Also can't see what it's powering. Clearly the drawings are incomplete; you may have to trace out the destinations for that rail yourself. If you measure the voltage at the - terminals of the two caps either side of the inductor, and measure the DC resistance of that inductor (if you have a 4-wire DMM) you should be able to see roughly how much current is being drawn by the amount of volts drop.

author: mojorizing
author_rank: Contributor
timestamp: November 01, 2021, 07:19:00 am
content: I don't think those schematics are correct. I have my working DS1102E opened up and with the power supply ribbon cable disonnected, and putting on the power, #9 is -9.15vdc. My #6 and 7 are 3.4vdc and my #3 & 4 are +6.4vdc and my #2 is 13.8 vdc.With the ribbon cable still disonnected, on the pcb connector pin #9 reads 364k omhs to ground.My power supply looks like yours, I'd have to study your pics to compare the rest.

author: taylorit
author_rank: Newbie
timestamp: November 01, 2021, 08:56:54 pm
content: Thanks for testing your PSU. All the rest of my voltages are the same as your and that diagram. So I think safe to say its not a power supply fault. I have tested the relays on board and they switch fine. So must be what ever is signaling the multiple 74HA595's that drive the relays. Looking at the front-end, there is 1x Relay for input attenuation once input scale changed it switches in RES/CAP network. Then another one for AC/DC coupling and then a 3rd one that switches the ADC input. I have injected the Sq Wave test signal to the poles on this 3rd relay and the signal is seen on the screen. I see the one in the below diagram 74HA595 #1 switches all three relays for channel one, and there must be another that does for channel 2.http://rigol.codenaschen.de/images/0/0c/DS1052E_HW58_PCB_Schematics_-_Ch1_analog_front-end.jpgThese look to be triggered by 74LVC2G17 Dual non-inverting Schmitt trigger. But after that, the diagrams are somewhat lacking.https://www.nexperia.com/products/analog-logic-ics/asynchronous-interface-logic/schmitt-triggers/series/74LVC2G17.html

author: mojorizing
author_rank: Contributor
timestamp: November 01, 2021, 11:49:46 pm
content: As a review:1) you have no output traces from either channel unless you inject a signal on the outputs of relay 1C and relay 2C? Or is only one channel NFG?2) no relays click after pressing "AUTO" on the front panel?3) you have a VOM to troubleshoot but no other oscope?My guess for the path of the control signals are processor> 74LVCG17> '595> relay. I don't think it the relay because you would get a trace, although coupled wrong or scaled wrong, etc. I'm thinking you have a power supply problem at the component level. There are test points galore on this machine so your VOM will come in handy.I'll detach my power supply from the case, and remove my fan. How did you get the lid removed for the shielding box for the inputs? I've bent back the three tangs and lifted the lid but I don't have clearance to slide it out because of the frame behind the display. I just notice the bottom shee tmetal is riveted to the front sheet metal.

author: mojorizing
author_rank: Contributor
timestamp: November 02, 2021, 12:53:10 am
content: I've removed my main board and plan to lay it out to get some data and pics.Looking around I found that the schematics you referred to are from this post >>>https://www.eevblog.com/forum/blog/rigol-ds1052e-nasty-surprise!/?allIn that post are 2 valuable pieces of info:Code:Mainboard PCB, Top view:(rectangular units in cm)------------------------------------0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6__0 _______________________ | |1 | |  _ | |2 |  | | |_________________| |___| |___3 | | | o|4 |# | |  |5 |# |____________| |6 |# (A) o |7 |# (D) (A)  |8 \o o (A)  o|9 \___________________________________________________|PCB legend:---------------------------o : Mounting screw holes# : Power connector : Number "X" regulator(A) : ADC (AD9288)(D) : DAC (AD5660)Power connector:--------------------------________________| 1| -GND- || 2| (+15V) || 3| (+6V4) || 4| (+6V4) || 5| -GND- || 6| (+3V4) || 7| (+3V4) || 8| -GND- || 9| (-12V) ||10| (50Hz_In) ||11| (/LCD_Bl) ||12| -GND- |----------------===========================================================Power sources:------------------------------(+6V4):----------------- Regulator 1- Regulator 2--(+3V4):----------------- Regulator 6- Regulator 7- Analog Devices Blackfin I/O- Analog Devices ADCs- Lattice MachXO- Spansion FLASH- Issi SRAM- Hynix SDRAM- Ramtron FRAM-- Philips ISP1362 USB On-The-Go- Video (UPS051, THS7316)-- Keypad PCB--(-12V):----------------- Regulator 3- Analog front-end- Cooling fan--(+15V):----------------- LCD moduleRegulator 1:----------------Type: NCP1117Case: SOT-223Output: 5.01VBias: 39A+85A (249Ω+750Ω)Powers:- Regulator 5- Front USB(+) through CEM4435A- Video (UPS051, THS7316)- 100MHz Osc. (74HC04)- RS232 ADM202--Regulator 2:----------------Type: NCP1117Case: SOT-223Output: 5.01VBias: 39A+85A (249Ω+750Ω)Powers:- Regulator 4--Regulator 3:----------------Type: L7905CVCase: TO220Output: -5.0VBias: NonePowers:- Analog front-end- Analog section- Trigger--Regulator 4:----------------Type: LP5951MF-3.3Case: SOT23-5Output: 3.3VBias: NoneSMD marking: LKHBPowers:--Regulator 5:----------------Type: NCP1117Case: SOT-223Output: 2.50VBias: 39A+39A (249Ω+249Ω)Powers:--Regulator 6:----------------Type: NCP1117Case: SOT-223Output: 1.25VBias: Adj pin to GNDPowers:- Analog Devices Blackfin core--Regulator 7:----------------Type: NCP1117Case: SOT-223Output: 1.25VBias: Adj pin to GNDPowers:- Altera Cyclone III--Code:Mainboard PCB, Top view:(rectangular units in cm)------------------------------------0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6___0 _______________________ | |1 | |  _ | |2 |  | | |_________________| |__| |__3 | E | A A|aa (h) i k o @|4 |% | B C B C|  g j l m n |5 |% |_D_____D____| f |6 |% F D L K b d @ |7 |% F I (b)b c e  p |8 \@ F F H F (b)b  q @|9 \____G__G_J_______@________________________________|------------------------------------------------------------------------------------------------------------------| PCB components & peripherals: | Power source(s): || |-----------------------------------------------------------------------|| | -5V0 |+1V25#1|+1V25#2| +2V50 | +3V4 | +5V0a | +5V0d | +15V0 | +3V3#2||----------------------------------------+-------+-------+-------+-------+-------+-------+-------+-------+-------|| @ : Mounting holes | - | - | - | - | - | - | - | - | - || % : Power connector | - | - | - | - | - | - | - | - | - ||[*]: Numbered voltage regulator | - | - | - | - | - | - | - | - | - ||----------------------------------------+-------+-------+-------+-------+-------+-------+-------+-------|-------|| A : AD8510 (Low input bias Op-Amp) | Y | | | | | Y | | | || B : AD8370 (Variable Gain Amp) | | | | | | Y | | | || C : LMH6552 (Differential Amp) | Y | | | | | Y | | | || D : 74AHC595 (8-bit shift reg) | | | | | | Y | | | || E : TLC272 (Dual Op-Amps) | Y | | | | | Y | | | || F : TLC274 (Quad Op-Amps) | Y | | | | | Y | | | || G : 74HC4051 (Single 8-Ch mux/demux) | Y | | | | | Y | | | || H : 74HC4053 (Tripple 2-Ch mux/demux) | Y | | | | | Y | | | || I : AD5660 (16-bit DAC) | | | | | | Y | | | || J : EL1881 (Sync. separator) | | | | | | Y | | | || K : ADCMP562 (Dual PECL comparators) | Y | | | | Y | Y | | | || L : LMH6574 (4 to 1 video multiplexer) | Y | | | | Y | | | | || a : 74LVC2G17 (Dual Schmitt-trigger) | | | | | | | | | Y || b : AD9288 (Dual 8-bit ADC) | | | | | Y | | | | || c : EP3C5F256C8N (Cyclone III FPGA) | | | Y | Y | Y | | | | || d : LCMXO256C (Lattice LUT) | | | | | Y | | | | || e : IS61LPS25636A (Issi SRAM) | | | | | Y | | | | || f : 74AHC04 (100MHz oscillator) | | | | | | | Y | | || g : UPS051 (LCD controller) | | | | | Y | | Y | | ||(h): THS7316 (3-Ch video amplifier) | | | | | | | Y | | || i : TCM809 (3.08V Reset Monitor) | | | | | Y | | | | || j : TL072C (Dual OpAmp) | Y | | | | | | | Y | || k : FM24CL04 (Ramtron FRAM) | | | | | Y | | | | || l : ADSP-BF531 (BlackFin) | | Y | | | Y | | | | || m : H57V1262GTR (Hynix SDRAM) | | | | | Y | | | | || n : S29GL064N90 (Spansion FLASH) | | | | | Y | | | | || o : CEM4435A (20m? P-Ch MOSFET) | | | | | | | Y | | || p : ISP1362 (USB controller) | | | | | | | Y | | || q : ADM202E (RS232 interface) | | | | | | | Y | | ||----------------------------------------+-------+-------+-------+-------+-------+-------+-------+-------+-------|| TM056KDH02 (LCD module) | | | | | | | Y | Y | ||----------------------------------------+-------+-------+-------+-------+-------+ ------+-------+-------+-------|| Keypad PCB | | | | | Y | | | | |------------------------------------------------------------------------------------------------------------------(*) mounted on the Bottom Layer.TCM809 reset supervisor directly resets the DSP, the USB and the LCD controllers and probably the FPGA,as well as the DS1000D series Active Logic Head.Power connector:--------------------------________________| 1| -GND- || 2| (+15V) || 3| (+6V4) || 4| (+6V4) || 5| -GND- || 6| (+3V4) || 7| (+3V4) || 8| -GND- || 9| (-12V) ||10| (50Hz_In) ||11| (/LCD_Bl) ||12| -GND- |----------------===========================================================Power distribution:-----------------------------------PSU PCB voltage outputs:--------------------------------PSU (+6V4):------------------ Regulator #1- Regulator #2PSU (+3V4):------------------ Regulator #6- Regulator #7- Keypad PCB- ADCMP562 (Dual PECL comparators)- LMH6574 (4 to 1 video multiplexer)- AD9288 (Dual 8-bit ADC)- EP3C5F256C8N (Cyclone III FPGA) I/O- LCMXO256C (Lattice LUT) I/O- IS61LPS25636A (Issi SRAM)- UPS051 (LCD controller)- TCM809 (3.08V Reset Monitor)- FM24CL04 (Ramtron FRAM)- ADSP-BF531 (BlackFin) I/O- H57V1262GTR (Hynix SDRAM)- S29GL064N90 (Spansion FLASH)PSU (-12V):------------------ Regulator #3- Cooling fanPSU (+15V):------------------ LCD module (TM056KDH02), through a 100? (01A) resistor- TL072C (Dual Op-Amp)Mainboard voltage regulators:-------------------------------------Regulator #1: (+5V0d)------------------------Type: NCP1117Case: SOT-223Output: 5.01VBias: 39A+85A (249?+750?)Marking: 1117BPowers:- Regulator #5- TM056KDH02 (LCD module)- Front USB(+), through CEM4435A MOSFET- 74AHC04 (100MHz oscillator)- UPS051 (LCD controller)- THS7316 (3-Ch video amplifier)- ISP1362 (USB controller)- ADM202E (RS232 interface)Regulator #2: (+5V0a)------------------------Type: NCP1117Case: SOT-223Output: 5.01VBias: 39A+85A (249?+750?)Marking: 1117BPowers:- Regulator #4- AD8510 (Low input bias Op-Amp)- AD8370 (Variable Gain Amp)- LMH6552 (Differential Amp)- 74AHC595 (8-bit shift reg)- TLC272 (Dual Op-Amps)- TLC274 (Quad Op-Amps)- 74HC4051 (Single 8-Ch mux/demux)- 74HC4053 (Tripple 2-Ch mux/demux)- AD5660 (16-bit DAC)- EL1881 (Sync. separator)- ADCMP562 (Dual PECL comparators)Regulator #3 (-5V0):------------------------Type: L7905CVCase: TO220Output: -5.0VBias: NoneMarking: L7905CVPowers:- AD8510 (Low input bias Op-Amp)- LMH6552 (Differential Amp)- TLC272 (Dual Op-Amps)- TLC274 (Quad Op-Amps)- 74HC4051 (Single 8-Ch mux/demux)- 74HC4053 (Tripple 2-Ch mux/demux)- ADCMP562 (Dual PECL comparators)- LMH6574 (4 to 1 video multiplexer)- TL072C (Dual OpAmp)Regulator #4: (3V3#2)------------------------Type: LP5951MF-3.3Case: SOT23-5Output: 3.3VBias: NoneMarking: LKHBPowers:- 74LVC2G17 (Dual Schmitt-trigger)Regulator #5: (+2V50)------------------------Type: NCP1117Case: SOT-223Output: 2.50VBias: 39A+39A (249?+249?)Marking: 1117BPowers:- EP3C5F256C8N (Cyclone III FPGA)Regulator #6: (+1V25#1)------------------------Type: NCP1117Case: SOT-223Output: 1.25VBias: Adj pin to GNDMarking: 1117BPowers:- ADSP-BF531 (BlackFin) coreRegulator #7: (+1V25#2)------------------------Type: NCP1117Case: SOT-223Output: 1.25VBias: Adj pin to GNDMarking: 1117BPowers:- EP3C5F256C8N (Cyclone III FPGA) coreNot sure if you've seen those.

author: taylorit
author_rank: Newbie
timestamp: November 02, 2021, 09:19:18 pm
content: Hi, thanks for the information you kindly shared. I had an idea to reflow the main board given none of the relays were working at all. Thought that all 6 relay controls faulty..? issue must be further upstream. So I got out the heat gun and went over the board. I also applied more heat to the Cyclone Chip with golf ball contacts. Let it cool down, and powered it up... and click click click it went.. ran a calibration and back to working :-) happy days. Added some pics of the chip I heated the most and of the main board over all. Thanks everyone for your inputs and ideas. Cheers