hybridfree/eevblog-posts huggingface dataset:
Project CD Box RS - ripped solder pad - can't figure out where it should lead - Page 1
Forum section: electronics / repair

author: mvno_subscriber
author_rank: Regular Contributor
timestamp: May 05, 2020, 09:07:09 am
content: Hi,I'm trying to repair a Pro-ject CD Box RS (a CD player). The previous owner wanted to extend the cable from the external power supply and managed to switch polarity - the result being two ruined voltage regulators inside.I'm relatively new to SMD and hot air, and managed to rip off a solder pad. I couldn't see any traces to it on the solder mask, so I thought perhaps it's a multilayered board. Thankfully, the two voltage regulators are set up in identical fashion so I thought I should see where the same pin on the other regulator went.However, I've probed around on all components and pins (I think), and can't for the life of me figure out where that pin goes. Ithinkit's the VREF pin (no markings on IC, so assumed pin 1 was down left relative to the writing on the chip). Voltage regulator is L5970D.Could it be that the VREF pin isn't used in the design at all, and left open? Or is there any typical place I could look?

author: wraper
author_rank: Unknown
timestamp: May 05, 2020, 10:05:44 am
content: VREF pin of L5970D is normally left unused.

author: mvno_subscriber
author_rank: Regular Contributor
timestamp: May 05, 2020, 11:37:43 am
content: Quote from: wraper on May 05, 2020, 10:05:44 amPerhaps this is my lucky day, then! Slowly getting there (realizing I had to turn my IR preheater to 300C+ to make the topside of the board warm enough for the hot air gun to work well enough took some time and nerves). Maybe I'll get a nice CD player in the hi-fi, after all.
Ripple & hum on Audio amp power supply - Page 1
Forum section: electronics / repair

author: harry
author_rank: Newbie
timestamp: January 16, 2023, 12:11:42 am
content: My Dell 5.1 channel audio amp has developed a loud hum in the surround sound speakers.The power supply looks like a classic transformer with four diode bridge connected to an electrolytic capacitor and IC voltage regulator.The power supply filter cap terminals show 300mv of ripple at 21 volts DC.Is this too much?The output stages are fed directly by the output of this capacitor.Some input stages are fed via a 12 volt output IC regulator that removes most of the ripple on those stages.There is lots of hum on the speaker outputs, and it's waveform looks like the power supply ripple on the capacitor.I removed and tested the power supply capacitor. It is "KSC" brand, labelled 6800 uf / 50 volt.On a Der EE LCR meter, it measured 6200 uf, with a dissipation factor of .112 at 100hz.ESR showed "0.0" which I interpret as less then 150 milliohm.A 4000 uf cap in connected in parallel reduced the ripple voltage from about 300mv to 200mv, with some reduction in speaker hum.Is 300 mv ripple too much on the PS?The filter cap isn't great, but not bad enuf to account for the hum on the four surround speakers.Also, I do not hear a hum on the subwoofer, which is powered by the same amplifier.Unfortunately, I do not have a schematic, so anything I do has to be extra simple...Where would you look to find the source of the hum?Thanks,Harry

author: harry
author_rank: Newbie
timestamp: January 16, 2023, 03:21:35 am
content: ADDED INFO:The frequency of the ripple is about 120 hz.Because 120Hz is 2x the freq coming out of the transformer, I infer that all four bridge diodes are ok. I have also individually resistance checked the bridge diodes in-circuit and they seem ok.

author: bdunham7
author_rank: Super Contributor
timestamp: January 16, 2023, 03:41:25 am
content: It's probably not too much ripple, the output stages should reject PS ripple. However, there may be a malfunction that causes it to not do that properly. The fact that an additional capacitor caused a reduction in the hum is interesting, although I'm not suggesting that a larger capacitor would be the fix.What is the amplitude of the hum output with the inputs disconnected? Have you verified that the 12V regulated power supply has no ripple? If so, how low was it? Can you post a good photo or photos of the board so we can make some educated guesses as to how the circuit is set up?
Riser Bond RD 6000 DSL - Page 1
Forum section: electronics / repair

author: Ivan_R
author_rank: Newbie
timestamp: October 25, 2020, 01:10:35 pm
content: Hello. I need to repair the Multi-Function Cable Test Instrument model RD 6000 DSL but I cannot find any information about it (service manual, electrical diagram or anything else). the instrument has a problem with the battery power. also it fails auto-calibration (Resistance and RFL mode)
Roberts Blutune T2 DAB radio stuck in F/W upgrade mode - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: February 19, 2023, 11:55:16 am
content: I bought a Roberts Blutune T2 DAB/FM BT radio which powered up and displayed F/W upgrade mode.I tried many combinations on the select/menu buttons during power up and after power up to reset the radio, all to no avail.As Roberts radio do not have a Firmware upgrade for this radio and I could not find a reset button or identify the reset pin on the DAB module, I resorted to more radical measures.I removed the four screws in the back and unscrewed the aerial then unsoldered the black wire attached to the aerial reflector. After pushing the lugs at each side of the top to remove it, I could then remove the DAB moduleI removed the DAB module Flash memory ( MX253233FM2I-08G or cFeonQ32C-104HIP) and saved the "stuck in F/W upgrade" binary imageI then bought a working radio and extracted the working flash memory. I saved the working binary image and then put back the working flash memory.I then programmed a new flash memory chip with the working image (V 1.03 ) and fitted it to the original stuck dab module.When the radio was reassembled it worked fine. Now I have two working radios!I performed a factory reset to ensure that I could read all the stations in my areaI have attached the working binary image in a zip file below to help others in this situation as well as a picture of the board.If anyone knows how to reset this radio from the update mode without changing the flash memory, I would like to hear about it !
Roberts BluTune50 dab radio tuning knob faulty - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: January 16, 2021, 05:23:44 pm
content: The symptoms are that all controls work but rotating the tuning knob for menu or station selection has no effect. Replacing the rotary control had no effect.This radio although made by Roberts uses the Imagination Technologies KINO4 DAB processor used in Pure radios such as the H3, H4 and H6The controls use four Analogue to digital inputs on the KINO4 processor.For example2.5Volt ref--> 10k---> A to D input-- > 33 ohm --> switch to gnd --> 1.5k -- > switch to gnd -->2k switch to gnd -->2.2k switch to gnd -->4.7k switch to gnd --> 6.8k+12K switch to gnd -->46k --> one side of tuning rotary controland2.5Volt ref--> 10k---> A to D input-- > 33 ohm --> switch to gnd --> 1.5k -- > switch to gnd -->2k switch to gnd -->2.2k switch to gnd -->4.7k switch to gnd --> -->65k --> second side of tuning rotary controlThe other two chains do the volume controlMeasuring the voltage on any switch should be 2.5Volt as normally no switch is closed. However one chain was at 1.34 V and getting progressively lower as the point of measurement moved away from the A to D input.So a short low down the chain which I could not find on the removed switch boards. I then noticed on the mother board switch board socket a track led off to the display connector and when I removed the display connector 2.5 volts returnedThe fault was a solder hair under one of the two Sleep switches in parallel at the bottom of the chain situated above the display! Reflowing the solder cured the problem and removed a 1K resistance across the switchesAs this was at the bottom of one chain only the rotary control was affected.
Roberts DAB Radio, DreamTime model, dim display - Page 1
Forum section: electronics / repair

author: fixit9660
author_rank: Newbie
timestamp: September 08, 2022, 01:29:56 pm
content: I've got a Roberts Dreamtime DAB Radio with a display that is almost to dim to see. The DIM button makes it dimmer. The radio works fine with the exception of the display. Before I dive in looking for things gleaned from a lifetime of electronic build and repair, does anyone have a schematic/circuit diagram, or any knowledge about this please?

author: rh100605
author_rank: Regular Contributor
timestamp: February 19, 2023, 02:27:23 pm
content: If the display is an OLED you must replace it.If the display is an LCD then you can replace the backlight LEDs. These are normally on a long thin pcb which you need to lift in the middle to get the ends out of the plastic surround.The LEDs are normally 0603 white or cool whiteHappy fixingRob

author: wasedadoc
author_rank: Super Contributor
timestamp: February 19, 2023, 02:44:16 pm
content: From the photos I have seen it looks like an LCD. As you will know if you have any device with an LCD display and a contrast pot, the wrong setting can give a very low contrast display irrespective of backlight illumination. My experience is that LCDs themselves in general do not fade, at least not significantly, so if the backlight is as bright as ever I would investigate the LCD driving circuitry before assuming you need to change the LCD.

author: cmkessell
author_rank: Newbie
timestamp: January 21, 2025, 10:41:56 am
content: Hi,We also have a Roberts Dreamtime with a very dim display. Did you ever manage to solve the problem?Thanks
Roberts Istream2 Istream 2 internet radio faults - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: June 25, 2025, 04:53:22 pm
content: I have recently tried to repair six of these radios that refused to power up. My guess is that people have used a mains adapter that is greater than 7.5 Volts.The Istream2 is worth fixing as it will receive the new format BBC radio internet channels when upgraded to the latest firmware. I used the wifi connection and upgrade menu, you could also upgrade the flash directly using a programmer.Normally the radio consumes about 50ma when not powered on. When faulty is draws hundreds of ma at 7.5 volts.Measuring the resistance to ground of pins 1,2 and 4 of the DAB/Internet module FS2026-0500-0037, should be greater than 10Kohm. Pin 3 is groundThe applied voltages on the 60 pin connector (when the DAB module is removed) should be P1=3v3 Pin2= 4V Pin4=1.2VThe 3v3 switching regulator is inside a screening can at the bottom right of the board. (see photos).The most frequent fault is that the switching FET FDG358 ( available from DigiKey) has shorted drain to source , applying the 7.5volt supply voltage to the 3v3 rail to the DAB module.The Sot23-5 switching regulator from Torex marked L1xx can fail as well. In really bad cases the ferrite in series with the 3v3 rail is damaged.The FS2026 (Venice 6.5) module is used in the Roberts R1, Pure Evoke F3 and maybe other radios. the post "Frontier Silicon firmware binaries" on GitHub is a flash repository by radio model and FS board number/name.A working module from another radio can be installed after changing/swapping the Flash memory and the two aerial connections.However check the faulty module for shorts internally on specific integrated circuits. Many ICs can be isolated by removing ferrites. In one case the DRAM ic was the cause of the short and was relatively easy to replace. The Chorus-3 FS1230A processor is difficult to remove and source (225 pin BGA).In one case replacing the DAB module with one from a working radio allowed the radio to power up but halted at "Waiting for PC wizard".I have yet to identify the fault on the board. May be the 3.3 volt regulator was not the only item to fail or the 3.3v is used on the board and damaged something else when it was at 7.5volts !

author: rh100605
author_rank: Regular Contributor
timestamp: June 30, 2025, 03:00:47 pm
content: I was asked about the flash code and flash device to update the Venice6.5 module from another radio ( In my case a Roberts 104 )Attached is the flash binary. The device is AT45DB321E in 528 byte block mode.You could of course just move the flash chip from the faulty DAB module to the working one if you are sure it is not damaged.The default aerial for Wifi is a loop aerial on the module you will often need to uncouple the loop solder link before attaching the coax and closing the other link.
Roberts Model 3001 Insulation Tester - Page 1
Forum section: electronics / repair

author: WaveyDipole
author_rank: Frequent Contributor
timestamp: January 10, 2020, 05:23:44 pm
content: I discovered that my insulation tester has failed recently. I haven't used it in a while but it was working when last used. The readings made no sense and when I checked I found that there seems to be almost no output.The oscillator for the high voltage generator is a TL494 PWM chip which has two outputs. These are coupled together and fed into the TX via a 100Ω resistor. There is an output at about 6kHz form the IC. I checked the oscillator transistor which is fine. The TX primary and secondary both have continuity. The secondary, which is ground referenced at one end, has an output of approximately 256VAC. The output end feeds into a stage with two 0.047 HV caps and diodes. I checked the output of this stage and I get approx 620VDC and 1200VDC so the HV generator itself appears to be working. There is a round thick black disc with no markings further up the board but without a diagram I can't tell where in the circuit it is positioned, but I presume that it is there for protection. I lifted one end and tested with it disconnected, but still no output.Next comes the tricky part. The DC output feeds into a 100kΩ resistor. One side has the full voltage, the other only about 180VDC. The resistor reads at just under 100kΩ on the DMM so it looks OK. I could really do with a circuit diagram to understand what happens next but I just can't find one anywhere. Does anyone have a diagram for the Robin model 3001 please? Failing that, I guess I will need to spend some time reverse engineering the circuit before I can proceed, but I thought I would ask first. Also, has anyone repaired one of these that could provide some pointers perhaps?

author: WaveyDipole
author_rank: Frequent Contributor
timestamp: January 19, 2020, 10:36:40 am
content: Ah well! I guess it was a long shot!
Roberts MP53 Display Backlight Failure Repair Notes - Page 1
Forum section: electronics / repair

author: fixy88
author_rank: Contributor
timestamp: October 05, 2022, 08:17:03 am
content: Some repair notes in case it helps someone else with this fault.Roberts MP53 table radio had display characters visible but no backlight aside from a brief flash on power up. Upon disassembly and testing a faint backlight was visible and would flicker more brightly occasionally when adjusting backlight brightness in menu.Backlight supply was traced to an LD1117A adjustable regulator marked IC7 on the main PCB and found to have an unstable and low output voltage. SMD resistors next to the regulator were tested and the 180 ohm found to be open circuit, the 560 ohm was ok. The 180 ohm resistor was replaced and backlight was restored. These resistors set the LD1117A output voltage at 5.16v when working correctly.The brightness of the display backlight is adjusted by the main MCU controlling a nearby SMD transistor in series with the LED K line and ground.
Roberts Radio RD70 receiver challenge - Page 1
Forum section: electronics / repair

author: murwil
author_rank: Newbie
timestamp: November 13, 2024, 05:54:03 pm
content: I have a Roberts Radio RD70 that has a constant static sound noticeable at zero or low volume. It is NOT present at the earphone socket so I have traced it down to the small audio amp chip (IC4). I do not have a circuit diagram but I am suspecting this chip or supporting components. There are a few electrolytics close by but I’ve removed a tested them and they seem well within tollerance. The only markings I can see on the audio chip are 01311 2005. It’s a small 8 pin chip but I can’t seem to find that specific one. The earphone out seems to have its own chip amplifier and as the static can not be heard there I’m suspecting this IC4.I have had zero success of locating a schematicI would be most appreciative if anyone can steer me to a circuit diagram or help me identify IC4. Any help would be very much appreciated. Thank you!

author: FIXITNOW2003
author_rank: Regular Contributor
timestamp: November 14, 2024, 01:06:35 pm
content: as marked 2005 could it be same as RD60 which uses a TPA2005D1DRBR audio chip

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 14, 2024, 01:33:39 pm
content: Quote from: murwil on November 13, 2024, 05:54:03 pmI'm not saying that it's the problem in this case but you can't really test capacitors for that kind of problem, replacing them is the only way to be sure.

author: murwil
author_rank: Newbie
timestamp: November 14, 2024, 01:44:16 pm
content: Thank you PA0PBZ. A very valid point. The caps are certainly easier to replace than the chip so I’ll follow that path. Do wish I could find a schematic of just the audio output.

author: FIXITNOW2003
author_rank: Regular Contributor
timestamp: November 15, 2024, 07:16:09 am
content: https://www.eevblog.com/forum/repair/roberts-rd60-dabfm-radio-repair-with-service-manual/RD60 circuits here if Audio stage same

author: murwil
author_rank: Newbie
timestamp: November 15, 2024, 05:31:29 pm
content: Thank you so much. While they are quite different radios these output stages are probably quite similar.

author: murwil
author_rank: Newbie
timestamp: December 09, 2024, 02:00:14 am
content: After much poking around I identified it to be a dry solder joint on that output IC.
Roberts Radio Stream 205 - Page 1
Forum section: electronics / repair

author: leo938
author_rank: Contributor
timestamp: February 13, 2022, 04:49:51 pm
content: Hello all,I have a Roberts stream 205 with significant speaker hiss. This hiss is present at all volumes (bar mute) regardless of mode ( e.g. FM, WiFi etc).It would seem to point towards on the speaker drivers.Would anyone have any pointers?Leo
Roberts RD60 DAB/FM radio repair with service manual - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: December 04, 2020, 01:27:52 pm
content: I recently bought a job lot of DAB radios, the first was a Roberts RIC 1 which only worked when pressure was applied to the side of the Mullard LP1175 Xtal IF can which had an open circuit primary. I depressed myself by looking inside only to find that the hard glue holding the tri-fillar winding bridged the ferrite and paxolin base. It had cracked. In my opinion irreparable.The second radio was a Roberts RD60 with the normal covering falling off. It powered up with no sound and the display kept returning to the same point.Looking on the Vintage Radio site I found a very helpful member who offered a pdf of the service manual. With his approval I have copied the service manual here. It is splt into two files due to the EEV forum upload limits.To remove the electronics you have to remove the handle. The ends of the handle have pins that go though the sides of the case and are held by circlips. Push off the circlips , pull out the pins and then remove the threaded inserts in the sides of the case.I removed the aerial and power inputs from the back and then the speakers leads. Then, with difficulty, removed the electronics. I removed the smaller screening cases over the two switching regulators and found +5 and 3.3 but the 1.2v was at 0.6v. Also the reset line was held at 1.4v.I removed IC8 － ABLIC S-8550AA-M5T1G and measured the resistance between 1.2v and ground as over 3K so it was worth replacing the chip. The reset chip IC10 － NCP803 2.93V now showed reset at 3.3v so the switching regulator had been pulling that down too (and probably up during reset).I bought a new regulator from Mouser UK and fitted the sot23-5 package. I used a microscope to do this. The radio then came back to life. Now to recover it.I have since found RD60 radios with no sound. The device marked 2005 in the screening can ( TPA2005D1-Q1 1.4-W Mono Filter-Free Class-D Audio Power Amplifier) was at fault

author: Greg J
author_rank: Regular Contributor
timestamp: February 03, 2025, 11:39:22 am
content: Amazing , thank you !We get these radios at Repair Cafe all the time - and any Roberts radio and schematic for it that I can get - it's always welcome. These are PITA to find faults in, especially those little modules on top.

author: brainwash
author_rank: Frequent Contributor
timestamp: May 15, 2025, 10:35:48 am
content: I have an RD-60 but it seems to be a different revision. The main PCB is completely different, mostly single-sided, with a different naming scheme. For example the original IC5 is now IC1, but still the same flip-flop. This makes debugging quite a bit harder.

author: brainwash
author_rank: Frequent Contributor
timestamp: May 16, 2025, 09:36:02 am
content: Detailed PCB photos part 1

author: brainwash
author_rank: Frequent Contributor
timestamp: May 16, 2025, 09:36:37 am
content: Detailed PCB photos part 2

author: brainwash
author_rank: Frequent Contributor
timestamp: May 16, 2025, 09:37:42 am
content: Part 3
Roberts Stream 93i internet radio, repair - Page 1
Forum section: electronics / repair

author: Glen.P
author_rank: Newbie
timestamp: December 06, 2023, 02:15:45 pm
content: Hi all,This is my first post. I’m in the beginner class and would like some help/guidance. I have had an issue with the Roberts Stream 93i internet radio. It was switched on and playing when it suddenly stopped. It has previously had no problems in years of daily use. It is powered by an ATL, AC Switching Mode Power Supply Adaptor with an input of 230V and an output of 12V⎓2.2A. I have tested the output voltage with a multimeter which gave an output of 12.26V.I am looking for guidance on what to check next. Am I correct in thinking that the capacitors on the top of the board would be next for testing, with each one needing to be desoldered individually? Are there other components more likely to have failed? Any help much appreciated. I have provided some images.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 06, 2023, 02:32:36 pm
content: noob question does it rely on a service provider to receive web radio, i had one who died that waythere was no provider for web radio anymore, now i use pc software instead ramradio or radio maximus ...Could be simple as that ... unless you have, bad solders, cold joints etc ... since you have 12vdcCheck the solders around your power amplifier ic, have they been reworked ?Try to find ic's datasheets you'll get some hintsMaybe the shielded cage must contain your web radio system hardware, operating system etc ... pictures seems fine, but no schematics ... you wont be able to do a thingas any network settings changed suddenly by say powering up another device who conflict ....i powered up an badly configured wifi router here, lol tons of people lost their web access lol until i shot it down after hearing the IT guys desperately searching for what happened ??

author: tunk
author_rank: Super Contributor
timestamp: December 06, 2023, 02:38:27 pm
content: No expert, but the PSU could still be bad even if itshows 12.26V. The voltage could collapse under loadand/or have high ripple.Edit:The digital electronics run at a lower voltage, so thereshould be some kind of step down circuit somewhere.

author: Glen.P
author_rank: Newbie
timestamp: December 07, 2023, 10:29:28 am
content: ThanksI managed to obtain another power supply to test it. The exact same thing happens, no power, not even to light up the screen. I'll investigate further.
Robin KMP 3050DL Insulation Tester - Page 1
Forum section: electronics / repair

author: rogerggbr
author_rank: Contributor
timestamp: January 07, 2025, 09:44:56 am
content: I recently acquired one of these but it does not work properly. The continuity works, but not the high voltage (250/500/1000V). A quick peek inside reveals nothing obvious but details of these seem hard to come by (schematics etc). I realise this is pretty niche, electricians will have moved on to much better/modern units by now, but for my hobby use I thought it would be useful. Any pointers on where to get some schematics would be appreciated, I am not sure I am up to reverse engineering it. It may be that the only way to fix these in the past was return to manufacturer and details have never been released. I will certainly do some closer inspections and checks though over the next week or so, thanks in advance. p.s. these are from the 80s/90s, the company was taken over and folded into Fluke, the name Robin lives on (was Robin Electronics Ltd). p.p.s. Other models 3010 and 3075 will share the same essential schematic.

author: Gyro
author_rank: Super Contributor
timestamp: January 07, 2025, 01:16:04 pm
content: It may be equally fruitless, but you may want to check for any repair hits for the Kewtech KT35. Irrc, a bunch of Robin engineers left for Kewtech (presumably when a takeover was on the cards). You ought to find that the schematic (which I haven't managed to find) is very similar.

author: fant
author_rank: Contributor
timestamp: January 07, 2025, 09:47:45 pm
content: I have two KMP3075, one working and the other broken.The broken one, in low Ohm is working fine, but on the high voltage any scale you use, it will show 250V on the display, the bargraph is beginning to raise and suddenly there is a beep and il will start again.Till now I have the schematic of the backlight of the display, but it will take time to complete it because I have one working.Mandi

author: rogerggbr
author_rank: Contributor
timestamp: January 08, 2025, 08:09:56 am
content: Update:- not found a schematic, but did look closer. Partially cleaned the contacts of the rotary switches (it looked clean inside but did it anyway) and now it works! These switches are similar to the ones seen inside handheld multimeters, contacts printed onto a PCB. Probably that is the only problem, bit more cleaning and hopefully fixed.
Robin KTS 1630 multifunctional tester - Page 1
Forum section: electronics / repair

author: wictor
author_rank: Regular Contributor
timestamp: January 12, 2024, 09:05:10 am
content: Hi,I have Robin KTS 1630 multifunctional tester, which was working and does not turn on properly anymore. It just turns all LEDs on and LCD does not display anything. There was no measurement ongoing when it stopped working. +5V seems to be present on most chips, but I haven't scoped anything yet.Problem looks like some initialization problem like MCU or PROM issue... Does anyone have schematic or other service documentation for this device. I would be also interested about PROM contents, if someone has copy of some FW version.Thanks,Wictor

author: wictor
author_rank: Regular Contributor
timestamp: January 14, 2024, 06:12:06 pm
content: One trace on display board was corroded. Fixing that seems to bring device back to life.
Robomow RM400 - Page 1
Forum section: electronics / repair

author: MichaelMai
author_rank: Newbie
timestamp: November 11, 2024, 05:12:14 pm
content: I have downloaded an RM Toolkit from a link i got on here. I am connecting to the PC with a USB serial converter, but i keep getting communication problems.The mowerer i have is an old one RM400, i changed the control board in it and the gwrman distributor said that i needed a software update. Mt Robomow dealer is unable to offer any support.
Robotron M1302 vibration meter service manual - Page 1
Forum section: electronics / repair

author: bborisov567
author_rank: Regular Contributor
timestamp: August 28, 2024, 08:41:23 am
content: I am looking for a service manual for the mentioned device. Currently there is no output on the display. I am wondering if there is a backup battery inside that could have leaked but currently i don't have access to the device to check. I know for sure it is a microprocessor based. Makes me wondering what systems were used by Robotron in the late 80's. Any information about the device would be useful, even a user manual. Cheers to all the german engineers here!
Rockspace Uzien C210 firmware - Page 1
Forum section: electronics / repair

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 28, 2020, 09:05:38 pm
content: Friends, someone has firmware for Rockspace Uzien C210 plotter?

author: Simon
author_rank: Unknown
timestamp: January 17, 2021, 08:44:07 am
content: Let's try again in English.
Rocktouch repair AJU90 chip - Page 1
Forum section: electronics / repair

author: holzbaer
author_rank: Newbie
timestamp: November 29, 2022, 08:36:01 am
content: Hi,Does anybody know what chip this is?It has a SOT23-6 housing and the marking goes AJU90.The chip is mounted on a 15" Cap-Touch with an EETI EXC3188 Controller - See pictures attached.Designator U1...
Rofin RF repair  - Page 1
Forum section: electronics / repair

author: Gravitech
author_rank: Newbie
timestamp: February 20, 2023, 08:09:07 pm
content: Hello, can anyone help us with the repair of a Rofin RF supply of the high-frequency cables, cuprexit plate, and High voltage resistor, see enclosed damageJiri Volf, Gravitech, CZ, jvolf@gravitech.cz

author: TheMG
author_rank: Frequent Contributor
timestamp: February 21, 2023, 01:10:59 am
content: Can we get a bit more context as to what we are looking at here? I seen some coaxial cables and a thick-film RF resistor.What sort of frequency does this operated at? Is this part of the device something to do with combining the outputs of the RF power amplifiers or something?At the very least, resistor will need to be replaced unless you can manage to solder on a new tab to what's left of the old one. Coax cables will need to be replaced due to the charring and likely heat damage to the dielectric. Be sure to replace with same type and length as phasing may be important.Other things to consider is whether there was any damage done to any RF final output transistors, due to the potential high SWR this fault would have created. Likely cause of the fault is probably a cracked solder connection, with the high RF energy it starts arcing and creating all sorts of destruction.That's about as much help as I can provide with the very limited information provided.

author: Gravitech
author_rank: Newbie
timestamp: February 22, 2023, 06:10:41 pm
content: Yes, it looks a cracked solder connection, we don't know if the resistor is ok, the laser did not go down with power before the error, so we think it's only the RF module, we are trying to find somebody from Europe to identify the cables, and fix them with the resistor, do yu know somebody in Europe to be able for repair, except Luxinar, they will refurbish the whole RF and we think this is not necessary....
Rohde and Schwarz FS3 Spectrum Analyzer Power Up Failure - Page 1
Forum section: electronics / repair

author: DrTom
author_rank: Newbie
timestamp: January 29, 2024, 01:37:57 pm
content: I have a RS FS3. It was coming on when plugged in but would not when "on battery". I bought a new battery but it wouldn't come on at all. I've inspected the PCB but don't see anything obviously burnt. Anyone have a schematic or suggestion on how to get it working?Thanks...Tom

author: m k
author_rank: Super Contributor
timestamp: February 01, 2024, 11:16:26 am
content: Maybe it's a simple battery contact problem.My guess is that the problem is not far from battery.Should be quite easy to follow the trace with DMM.

author: pdenisowski
author_rank: Super Contributor
timestamp: February 01, 2024, 01:20:46 pm
content: Sorry to ask, but is the battery charging when it's plugged in? Does the FSH show the battery as charged? If you bought the battery from us, it's not charged when it's delivered.If you bought it from a 3rd party: I've seen some permanently dead FSH3/6 batteries: like all rechargeable batteries, they have a finite lifespan and the FSH3/6 is an older platform (about 15 years since we stopped making them).At a minimum, I would use a DMM to check that it is holding a charge in the open state (i.e. battery unconnected to anything)
Rohde and Schwarz schematics for SMIQ etc. - Page 1
Forum section: electronics / repair

author: mr ed
author_rank: Regular Contributor
timestamp: September 11, 2022, 02:43:21 pm
content: Someone out there has schematics for the out of support R and S RF generators. The linkhttp://www.electronicsandbooks.com/edt/manual/index.php?dir=Hardware%2FR%2FRohde+%26+Schwarz%2FProduct%2FSMIQ%2Fhas scanned sheets but no schematics. One poster claimed schematics were included. I and others have shown no schematics exist. Its a scanned pdf and I bet thee scanner didn't bother with the large sheets.So, whats up? We need schematics.
Rohde and Schwarz synth schematic for SMIQ03E rf gen - Page 1
Forum section: electronics / repair

author: mr ed
author_rank: Regular Contributor
timestamp: September 01, 2022, 04:42:04 pm
content: I have a failed TSYN synthesizer card in my R and S SMIQ rf generator and no schematic. I have looked in all the usual places, no joy. I have the service text description but no schematic.Does anybody have this file or know where to get it? (r and S told me to go fly a kite).I have the SMIQ 03 E (which seems to use the SMT synthesizer card)TSYN A7 module 1039.2330
Rohde & Schwartz SME03 service kit SM-Z2 software (or availability) - Page 1
Forum section: electronics / repair

author: Tony_G
author_rank: Super Contributor
timestamp: May 02, 2016, 05:23:30 pm
content: Hi All,I recently fixed a R&S SME03 (the output attenuator needed a little TLC, cleaning and physical alignment). The service manual states that once the output attenuator is opened you need to reset the offsets using the software, and I assume physical pieces, in the SM-Z2 service kit.Unfortunately it seems that no one has that kit - I even called R&S directly and they checked with their warehouses in Asia and Germany (they showed it existing in their system) and discovered that they really didn't have stock. They do have the ability to calibrate the unit in their labs but that cost is US$1165 (which is about 3 times what I paid for the SME03).So I thought I'd ask here if anyone has the kit they'd be willing to rent out or at least the calibration software they could share.Hopefully someone has this.Thanks,TonyG

author: BeamDump
author_rank: Contributor
timestamp: January 18, 2022, 02:58:47 pm
content: I'm also curious if anyone has this service kit? (service manuals lists a program TEST_SMP.EXE) to run a deeper diagnostic on R&S signal generators.
Rohde & Schwarz 1091.2320 PULS 230 250 PSUs - where best to tap +12V? - Page 1
Forum section: electronics / repair

author: ci11
author_rank: Regular Contributor
timestamp: July 27, 2024, 02:39:40 pm
content: I am planning a CCFL to LED conversion. The factory inverter, the 0048.8766 aka Delta DAC-05B004, has 2x +5V in, but the potential replacement LED inverter requires +10V-24V.The Service Manual mentions +12V is available on the connector PSU connector at X20.D24. Do I really need to bodge from the mainboard or is there a more convenient location/connection?For those who has worked on this PSU, where is the best place to tap a +12V from?
Rohde & Schwarz CMS-50 input Ceramic substrate burned and "DSP Time out" - Page 1
Forum section: electronics / repair

author: BH3TXW
author_rank: Contributor
timestamp: February 23, 2023, 10:26:13 am
content: Hi all,Recently a friend acquired a CMS-50 with nice shape and appearance. But input attenuator/power splitter on white ceramic pad is burned, and DSP Time-out keep appearing on screen.For input attenuator. I suppose it is a Y shape power divider on ceramic substrate. There are 3 arms of this Y shape. The one connected to relays' board looks good, we checked it out with DMM which shows 16 Ohms. The one connected to front panel N-type I/O is apparently burned. The last one connected to detect diode side is also broken by crack across of it. We decide to restore this by adding chip resistors to make the machine at least capable of measuring hand-held radios. But we just can't figure out how much ohms should be on each broken arm.For DSP Time-out. We have extender cable attached. On Measuring Section, D500 DSP56002 is replaced, electro caps are replaced, all Vcc and Gnd are checked, and 20 MHz on EXTAL is also checked. On Digital Unit, D33 74HCT244T and D34 74HCT245T look like part of DSP interface, are replaced too. However, the error message "DSP Time-out" remains showing up and modulation and AF output are still crippled.Service manual we have is only for CMS52. Now we got no clue to sort it out. My friend doesn't speak English and I wonna help him out on this.Any suggestion or any input is appreciated!Thanks!Regards,James - BH3TXW
Rohde & Schwarz CMS-50 repair - Page 1
Forum section: electronics / repair

author: iw0hex
author_rank: Newbie
timestamp: January 22, 2021, 08:30:23 am
content: Hi guysI'm Pasquale IW0HEX, ham-radio operator, I live in Rome, Italy.I have a trouble with my Rohde & Schwarz CMS-50 Test Set.Exactly the front end is burnt, module is 840.1711 inside in Attenuator module 840.1657.04You can see the photos in attach.Could anyone help me with this issue ?Thanks in advancePasquale IW0HEX

author: BH3TXW
author_rank: Contributor
timestamp: February 25, 2023, 08:36:48 am
content: Hi Pasquale,I met the same problem. I'm working on repairment recently but got nothing in progress.Have you figured yours out?Thank you.James - BH3TXW
Rohde & Schwarz EZK freq controller - Page 1
Forum section: electronics / repair

author: LUBER41
author_rank: Newbie
timestamp: December 17, 2023, 07:34:12 pm
content: To repair a ROHDE & SCHWARZ EZK frequency controller i look out for a service manual. Can somebody help me. I do have an operator manual but that doesn't help me.
Rohde & Schwarz FSEA30 tracking generator option suddenly gone.. - Page 1
Forum section: electronics / repair

author: RF_fanatic
author_rank: Regular Contributor
timestamp: December 01, 2021, 09:17:51 pm
content: Hi friendsI have a Rohde & Schwarz FSEA30, very happy with it allthough I hardly used it due to the fact I also own some other spectrum analyzers which are less bulky and heavy for quick test.Last weekend I wanted to use my tracking generator on my FSEA but for some reason the option in the menu is gone.... allthough the hardware naturaly is still in....The only warning I noticed when starting up was: date might be incorrect.To be noticed I have not used it over a longer period, maybe even over a year, so would there be an internal tracking generator power part i could look at?Does anyone have a clue where to look? The unit has been standing on the same position over multiple years so I do not expect one of the cables suddenly went looose.

author: CrazyTiger
author_rank: Regular Contributor
timestamp: December 08, 2021, 02:17:12 am
content: Hi,Maybe the internal battery is dead, causing it to no longer detect the FSEA30 options properly. Your wrong time and date does indicate the battery is dead.First have you checked in the spectrum, its reading the model and serial number correctly? Cause when the battery dies it tends to go haywire, usually the model number default to FSEM or FSEB.In my case my FSEM30 was detected as FSEA30, It basically went from 26.5 GHz version of a tiger to a 3 GHz house cat.Lets check first if its detecting the model properly, also do check the back of instrument to see if they are stickers with the option codes.See sample below, picture taken from ebayGood Luck
Rohde Schwarz FSH8 SA basic teardown repiar and experiments - Page 1
Forum section: electronics / repair

author: Samogon
author_rank: Frequent Contributor
timestamp: June 30, 2018, 04:43:35 am
content: I just got FSH8 handheld 8GHz spectrum analyzer from auction with broken display lens. I took a risk with hope that this is only damage it got.I had FSH3 before and it was smaller, lighter than FSH8. And there is a reason. FSH8 is completely different beast, different engineering approach.FSH3 digital part was almost the same as Fluke 192 series oscilloscope.Fortunately for me SA was in good functional condition and i did not dare to open RF shielding can. So there are only pictures of naked can no RF porn.

author: Samogon
author_rank: Frequent Contributor
timestamp: June 30, 2018, 04:44:29 am
content: Repair was boring two week long negotiation registration and ordering parts from R&S. Probably no need to mention that parts from R&S are arm and legAlso ordered aftermarket battery claiming 10,000mAhOnce parts were delivered it took couple of hours to finish the job.Have to admin R&S accepts money from poor people like me, not snob like Keysight.

author: Samogon
author_rank: Frequent Contributor
timestamp: June 30, 2018, 04:46:29 am
content: reserved

author: DaJMasta
author_rank: Super Contributor
timestamp: June 30, 2018, 05:01:12 am
content: Not even a peak under the can?I think it being a different beast is right on the money, the FSH series is actually a whole slew of major revisions to the product - instead of just renaming them like other R&S stuff, they kept FSH and just kept making new analyzers altogether. I believe the order is something like FSH3+6 is the earliest variant, then the updated ones are marked like FSH3.13 or otherwise to indicate options, then the next version was the FSH4/8 introduction, no longer making the 3s and 6s, then I believe there's one revision beyond yours with a higher res screen and a different front styling. Not sure why they haven't differentiated the part names more, but I suppose I can understand why they'd want to keep the H for their handheld analyzers.Does that mean the screen is damaged, or just the protective cover?

author: Samogon
author_rank: Frequent Contributor
timestamp: June 30, 2018, 05:08:04 am
content: just EMI shielding lens. I was lucky this time.

author: drhex
author_rank: Regular Contributor
timestamp: February 21, 2024, 06:19:07 pm
content: Looks like you bought multiple lenses - R&S claims they don’t carry these anymore. Would you have one for sale?
[SOLVED] Rohde & Schwarz FSIQ7 not showing Tracking Generator Menu - Page 1
Forum section: electronics / repair

author: Astralix
author_rank: Regular Contributor
timestamp: March 30, 2023, 11:01:17 am
content: Hi!Just got an FSIQ7 back to life after someone had tinkered with it's RF EEPROM. But now all SELFTEST and FULL CAL procedures run through without any issues. Also all measurement results I could do show plausible results.But it has the option B10 "Tracking 7GHz w/o I/Q Mod" installed as A110 and the lable is also on it's back. Before I started the repairs, the R&S service / calibration labels where original and intact too.Opening the "MODE" menu the only options shown are "ANALYZER", "VECTOR ANALYZER" and "3GPP ANALYZER". The option "TRACKING GENERATOR" is missing. I checked the manual and compared it to my FSEB30, it is the place where the tracking option should to be found...Unfortunately or luckily there are no entries in the error log of the unit, like it was before when the RF EEPROM was currupted. So Tracking should work...Any idea?Thanks!Astralix

author: Astralix
author_rank: Regular Contributor
timestamp: April 20, 2023, 08:58:59 am
content: Even I got no replies, I'd like to close the case and post the solution:The mechanism to identify options mounted in the analyzer seem to got stuck when discovering the TG. Fortunately the FSEB30 I also own shares the exact same TG. So I swapped the FSIQ-TG into the FSEB and it was recognized and worked without any issue.As a second test I put the FSEB-TG into the FSIQ and it was also immediately recognized and worked.Finally I swapped both TGs back into their original units and both are now working in their original machines. Swapping TGs must have broken the loop the serial number recognition mechanism was stuck in.And before someone asks: I had tried the "hold . while booting" thing on the FSIQ but that did not recover the TG to work.

author: FBcomm
author_rank: Newbie
timestamp: April 20, 2023, 02:04:35 pm
content: Hi, I'm looking if anyone has the Rodhe & Schwarz polarad model 309 rf generator manual.thank you so much.
Rohde Schwarz FSP IF Board Failure - Page 1
Forum section: electronics / repair

author: Testtech
author_rank: Regular Contributor
timestamp: November 24, 2024, 10:22:05 pm
content: I am working on a new-to-me Rohde Schwarz FSP spectrum analyzer that has a failure on the IF board.The self test display is below.Anyone have experience with this model? I have the service manual, but no schematics, and the block diagram is of little help.It appears that the measurement circuitry on the IF board isn't working, or perhaps a logic problem.The main PSU is fine.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 25, 2024, 05:12:13 pm
content: Hi!I found FSP in a good condition:)I'll have a look.

author: DaJMasta
author_rank: Super Contributor
timestamp: November 25, 2024, 07:30:15 pm
content: Don't have experience with this unit, but it sure looks like the ADC, its reference, or its Mux is dead. You should probably run a test to see if the board itself is operational, and if it's capable of running at least some of its functions, it is probably a self check measurement failure.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 26, 2024, 10:55:26 am
content: Hi!I put 2.2k resistor between REFADJ (Pin12) and Gnd.Self-test results are now similar.Check the capacitor on pin12 first.As far as I remember, there are several MEGs between pin12 and Gnd.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 27, 2024, 07:10:25 pm
content: Hi, Testtech!Do you have any further info?Please don't hesitate to contact me.
Rohde & Schwarz HMC 8012 DMM Schematics? - Page 1
Forum section: electronics / repair

author: hbrown
author_rank: Newbie
timestamp: April 30, 2023, 12:56:31 am
content: It feels unlikely, but I'm looking for schematics or any service information on an HMC 8012 multimeter. I have one that won't power on and I only see one LED illuminated on the main board. I don't even see any power rail labels on the PCBs so I really don't have anywhere to start.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 03, 2023, 11:40:22 am
content: Ask the company under an non disclosure agreement if not i dont think youll find one on the web ... never found one up to nowgood luck

author: Kleinstein
author_rank: Super Contributor
timestamp: May 03, 2023, 11:46:34 am
content: AFAIK there are different versions of the 8012. At least one service manual including schematics is floating around in the web.

author: pdenisowski
author_rank: Super Contributor
timestamp: May 03, 2023, 12:59:25 pm
content: Quote from: Kleinstein on May 03, 2023, 11:46:34 amYes, the HM8012 and the HM8012C are very different instruments. A service manual for the (older) HM8012 can be found on the internet

author: coromonadalix
author_rank: Super Contributor
timestamp: May 03, 2023, 04:16:34 pm
content: Can you open the meter to see if it could be a clone of some sort, and sometimes the psu is separated from the main stuffshow us internal photos ... it could be easy ... or not loll

author: Wade2019
author_rank: Contributor
timestamp: May 07, 2023, 03:49:04 pm
content: I have repaired the problem of HMC8012 not turning on, most of which are due to the problem of solder joints between the motherboard and the panel connector. Please trust the hardware reliability of HMC8012

author: Wade2019
author_rank: Contributor
timestamp: May 07, 2023, 04:00:02 pm
content: picture

author: hbrown
author_rank: Newbie
timestamp: June 29, 2023, 01:29:07 am
content: Here is a picture of the main board and a close-up of the power supply. There are labels for +15V, +5, and 3v3_STB, It's just not clear to me where those labels are indicating to... This one is likely a total loss and destined for the trash bin but I was hoping to at least check the power supplies first. This meter was used in an environment around high-voltage test equipment and suddenly stopped working... I found one transistor on the front interface PCB with a hole in it right above the input terminal so it likely had a surge arc to the digital bits.