hybridfree/eevblog-posts huggingface dataset:
2SK216 + 2SJ79 Replacement FET´s for Denon PMA-1560 - Page 1
Forum section: electronics / repair

author: Morten
author_rank: Newbie
timestamp: August 29, 2017, 09:12:59 pm
content: Hi All.I am repairing a Denon PMA-1560 integrated amplifier, and i have found that one of the pre-driver FET´s, the 2sk215 i shorted, and therefor needs replaced.I have used a great deal of hours trying to find a reputable source for this replacement, none found, unfortunatly, it seems that they are not made anymore.At Ebay, i bought 5pcs. 2sj79 + 5 pcs. 2sk216 for 6 dollars, knowing that they almost certainly were fakes, but maby they were at least usable. Now 5 weeks after ordering them from some guy in china, they have arrived, and i tested them, my tester told me that they tested like a FET, yes the 2sk parts had a Vgs on of around 3,1v fairly high, the datasheet say max of 1,5v, and the 2sj parts had a Vgs of aroud 1,8v, closer to what the datasheet say.I mounted the parts in the outputmodule, attached my DMM on the bias testpoints, and fortunately i used my variac to bring up the voltage, at 20 volts in, i had 200mv of biasAfter some probing around i found that it seemed like the brand new FET´s were shorted drain - source, i pulled the part and tested it, no problem still tested like a FET on my tester, and my DMM agreed, no short.What i found was that the drain and source pins were switched inside the transistor, originaly the pinout is GSD, the new ones both the 2sk and the 2sj parts were GDS,come on..... when you make fake transistors, at least try to get the pinout right, these ones is going in the bin.Now i have ordered 2 transistors sold as New Old Stock, at 13 dollars, and this time in Germany, so with a bit of luck they should be here in Denmark in a couple of days.Now to the real question, can someone help me find some suitable replacements for those 2 transistors, i dont feel like paying 8-10 dollars for a transistor i am not sure is original the next time i need to repair a output module in a Denon PMA-1560, it would be nice if the new part is obtainable at RS, farnell or digikey.Hope someone is able to help me out here, i have found a couple of forum threads on other forums regarding this toppic, but there were no real conclution.Best regards from Denmark.Morten

author: ArcticGeek
author_rank: Regular Contributor
timestamp: August 30, 2017, 04:09:02 am
content: These are a bit unusual because of the GSD pinout, I think only Japanese semiconductors used that pinout.I think the 2sk2013/2sj313 complementary pair should be very close. You can get them at Analog Metric here:http://www.analogmetric.com/goods.php?id=1242I've never purchased from them, just found them doing a google search. They aren't much cheaper, they're about $9 US for the pair.Good luck.

author: Morten
author_rank: Newbie
timestamp: August 30, 2017, 11:13:01 am
content: Thank you for your reply :-)I will look in to those transistors, i had hoped to get something i little cheaper recomendet though :-)Other sugestions are also verry much velcome.Thanks
Help me repair Iwatsu SS-7821 200Mhz OSC - Page 1
Forum section: electronics / repair

author: chihaxinh
author_rank: Regular Contributor
timestamp: August 30, 2017, 02:15:18 am
content: Hi everybodyI have one Iwatsu SS-7821 OSC , similar SS-7804/06/10/11A Iwatsu OSC Series. One day when i using X-Y mode, Osc hang and i restart OSC . Boot hang and display only trigger led .You can see service manual in link belowhttp://www.iti.iwatsu.co.jp/manual/pdf/SS-7810-05-04_ServManl.pdfOk, when have time i open OSC and checking .- No display - Only have dot when press button Beam Find .- All button front panel hang ( display only Trigger led )Like troubleshot osc, i checking Horizon Amplifier and find out dont have ramp signal . And i follow in service manual , all signal grenarator Ramp control by TLC IC ( IC made by Iwatsu)Sawtooth BuffH&Z SWTimmingI goto TCL module and check Crystal , it's ok , i have 19.9999Mhz clockAnd some day thinking , and review OSC block . i go to check around CPU , and checking Serial Data because all block like timming, sawtooth, h&z sw , h output amp have controll by DA ( Analog Board 8bit D/A) . And i find out missing Serial Clock and Serial Data go to D/A board.ANA Board ControlANA 8BitI checking TLC and ANA Board Controll connect to one sub board ( only have in 7821 ) and i dont have schematics . Sub board connecting to TLC IC and have Print label ( Trig Sub G-K3653 D2). I see sub board have 3 IC logic . 2x 10HL131 (Dual D Type Master-Slave Flip-Flop), 1x 10HL107 (Triple 2-Input Exclusive OR) .I think module it's frequency counter or frequency divider . and some transistor SOT-23 layout like Pushpull amplifier ( High requency transistor ).I takeout all transistor and smd diode and checking, trans and smd diode dont broken or fail . It's OK.I checking by multimeter have VCC and GND around 600R , and i takeout 3 IC logic and checking VCC-GND IC logic , it's ok .I go back to subboard without IC and all transistor and diode ,and have same result , resistor between VCC-GND around 600R.I dont know why missing Serial Data and Clock Data to ANA Ctr and ANA D/A 8bit . I replay IC IC6 74W32 in ANA board Control dont give back clock.And i have one question, Serial clock and Data clock have 0.2V/div it's normanly ? Do you think CPU have problem ?Many thank so much!Nam Nguyen Hai
Dremel MSP430F2012 mixed signal muc LVC Bypass - Page 1
Forum section: electronics / repair

author: anishkgt
author_rank: Frequent Contributor
timestamp: August 29, 2017, 11:53:34 am
content: I was thinking of using my old Dremel as PWM controller for 775 motor.The thing powers up but there are two wires white and green that senses cell voltage for LVC that had 18650 cells and am not sure how to bypass it since the power source is no more a cell. The pcb has this MUCand the pcbAnother pcb that used to be connected to the 18650 cells.On checking the MUC i found this from TIhttp://www.ti.com/lit/ds/slas491i/slas491i.pdfI would appreciate if somebody could help me by pass the LVC.
18650 Manufacturer/Datasheet? - Page 1
Forum section: electronics / repair

author: edpalmer42
author_rank: Super Contributor
timestamp: August 28, 2017, 06:54:31 pm
content: I've got a 3 year old battery for my laptop. One pair of cells has gone bad so I'm going to replace them. Before I do so, I'd like to check the datasheet for the specs.I've tried to find this manufacturer, but no luck. I even tried TinEye to match the logo. The battery pack came from China, so I'm assuming the cell manufacturer is also Chinese. The pack reports that the cells are Sanyo. Probably not.Anybody recognize this logo?Ed

author: anishkgt
author_rank: Frequent Contributor
timestamp: August 28, 2017, 09:42:47 pm
content: Looks like a fake Sanyo. Probably a chineyo Moreover I've not seen logo on well know branded cells.Sent from my iPhone using Tapatalk

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2017, 01:00:13 am
content: https://fefirstbattery.en.alibaba.com/http://www.firstbattery.com/en/https://fccid.io/UL/FAR-EAST-FIRST-NEW-ENERGY-CO-LTD... passes UL safety tests. Not too bad.According to the datasheets you can find in the second link, 6E61214 is a 2000mAh cell produced in May 12 2014.

author: A@ron
author_rank: Contributor
timestamp: August 29, 2017, 01:57:28 am
content: Even if you were to get another 2000 mAh cell keep in mind that the other cells in this pack are 3 yrs old and might be much lower capacity. Without capaciting testing the others on something like an Opus you might still have some cells which are low capacity and will drag the rest of the pack down under use.Shame you're in Canada as I've got a hoard of 18650s and a battery tab welder here

author: edpalmer42
author_rank: Super Contributor
timestamp: August 29, 2017, 04:51:40 am
content: Quote from: amyk on August 29, 2017, 01:00:13 amThanks, amyk! That's definitely the right company. Odd about the capacity, though. The battery is claimed to have a capacity of 4400 mAh and is a 4S2P configuration. That would imply a 2200 mAh cell. Whatever. I've seen a lot more 'creative' battery capacity values!Ed

author: edpalmer42
author_rank: Super Contributor
timestamp: August 29, 2017, 05:04:19 am
content: Quote from: A@ron on August 29, 2017, 01:57:28 amWay ahead of you A@ron. I *do* have an Opus and I'm in the process of measuring the 3 good pairs. I use a DIY adapter that allows me to measure the pair without disconnecting everything. The first pair measured 3.7 ah - down from 4.4 ah after 3 years. I scrounged some laptop batteries and came up with a few good pairs. I'll pick the pair that matches the other ones the best.I've just finished rebuilding a second battery for this laptop. The original batteries were Sanyo from 2007!One pair was dead, but the other 2 pairs measured 3.0 and 3.1 ah! One of the scrounged batteries had Sanyo cells from 2008 with the same capacities.Will wonders never cease!Ed
TDS3000B dead channel ?? - Page 1
Forum section: electronics / repair

author: darkstar49
author_rank: Frequent Contributor
timestamp: August 25, 2017, 01:42:45 pm
content: Hi,got a TDS3034B from which channel 4 looks dead... i.e. with the internal 1khz signal, there are only small spikes (+- 100-200mv) at 1ms intervals, but also negative spikes, also at 1ms intervals, but shifted 0,5ms from the positive ones...Other channels are OK.Did not do anything so far, but has anyone encountered similar symptoms ?? error log only reports issues with the user interface (although it shows "CPU:9"... ??), but acquisition:0Any hints appreciated...

author: darkstar49
author_rank: Frequent Contributor
timestamp: August 25, 2017, 01:56:58 pm
content: just ran diag: everything passes...SPC: everything OK as well...

author: Jwalling
author_rank: Unknown
timestamp: August 25, 2017, 03:30:34 pm
content: Check for a broken connection between the BNC and the ACQ board. Common problem with the TDS3K series

author: zxase258
author_rank: Contributor
timestamp: August 29, 2017, 06:46:26 am
content: Check the input attenuator relay
Tek 465B Oscilloscope Strange Spot on Screen Moveable With Magnet - Page 1
Forum section: electronics / repair

author: cjs2pc
author_rank: Newbie
timestamp: August 28, 2017, 06:52:13 pm
content: Hi guys,I recently purchased a Tek 465B on eBay and have a weird display issue.There is a strange dead spot on my display always in the same position. It is a round circle where the trace is blanked out. At first I thought something had happened to the phosphor coating at that location and it was burned out.http://imgur.com/a/xVD8UHowever, when I place a magnet near the screen, the trace line is distorted as expected, but interestingly the dead spot moves with the trace, so it seems like this is an issue with the beam generation not the phosphor.Has anyone seen something odd like this before?

author: StillTrying
author_rank: Super Contributor
timestamp: August 28, 2017, 08:23:44 pm
content: I think it has to be a particle stuck on the CRT's post deflection mesh, but I don't know the solution, it may be a case of gently tapping the CRT in the right place - or not.

author: tggzzz
author_rank: Super Contributor
timestamp: August 28, 2017, 09:03:18 pm
content: Quote from: StillTrying on August 28, 2017, 08:23:44 pmI agree.Note that the mesh is very fragile, and might be damaged by a strong magnetic field. If the CRT is disassembled, even breathing on the mesh is sufficient to warp it.
Need help for fixing a Weller VP800 desoldering station - Page 1
Forum section: electronics / repair

author: marcaurell
author_rank: Newbie
timestamp: August 27, 2017, 05:28:57 am
content: I hope someone can help me. Sorry for double Post!Can someone give me the specification of this part. At my platine the designation is no longer readable. Reason for exchange: The PINS are broken!

author: Ian.M
author_rank: Super Contributor
timestamp: August 27, 2017, 05:38:26 am
content: JFGI:https://www.eevblog.com/forum/repair/need-help-for-fixing-a-weller-vp800-desoldering-station/and actually*READ*what's there, especially reply#3

author: marcaurell
author_rank: Newbie
timestamp: August 27, 2017, 06:15:06 am
content: Quote from: Ian.M on August 27, 2017, 05:38:26 amPlease help me I do not understand what you Point.I have again read it is thus a triac with the designation: TAG226-200?!http://www.semicon-data.com/scr/trc/ta/TAG226-200.htmlThis part is hardly more to get you know a working replacement or is my station waste due to this small part?

author: Ian.M
author_rank: Super Contributor
timestamp: August 27, 2017, 07:47:33 am
content: Its told you its a 200V 8A sensitive gate TRIAC. Did you read as far as reply#5 where the O.P of that topic substituted a Littelfuse L4008L6 (400V 8A sensitive gate) successfully? Also note Sean.B's comments about excessive dissipation in the SL443 in reply#14.

author: marcaurell
author_rank: Newbie
timestamp: August 28, 2017, 05:47:04 pm
content: I am not a specialist for such repairs I am an electrical specialist for cars so I have to ask again I can replace the defective triac simply by thishttp://www.littelfuse.com/products/switching-thyristors/triac/lxx08xx-qxx08xx-qxx08xhx/l4008l6tp.aspxYES or NO?And my english is not perfect please apologize.

author: Ian.M
author_rank: Super Contributor
timestamp: August 28, 2017, 05:56:02 pm
content: That's the part the O.P of the other thread used. However it will only help if your SL443A Zero voltage switching Triac driver isn't damaged. The SL443A is discontinued, very hard to find as genuine N.O.S, and the ones on EBAY aren't to be trusted.
Falcon DSO-025C1 display problem - Page 1
Forum section: electronics / repair

author: vish2207
author_rank: Newbie
timestamp: August 28, 2017, 10:34:00 am
content: I have Falcon DSO-025C1 with 25 MHz Bandwidth 2 channel. It doesn't show anything on the display.It was working in very fine accept one problem, the brightness on the LCD was randomly varying when just touching the preset of the brightness on the front panel.I am talking about the brightness preset shown in one of the DSO_OFF.jpg attached here on mid bottom horizontal right beside the label of company and model number.One of the image attached shows the DSO when it is on. It just shows some light purple screen and nothing else. Even changing the brightness preset doesn't affect.I tried to verify the operation of the DSO by connecting probe to test pin on the DSO itself which gives 5V 1KHz square wave output and pressed AUTOSET button. I can here some relays are switchin inside, so it seems it is working but there is nothing on the display.How should I debug? Which section of the DSO should I probe first to look for problems?
R4131 Advantest SPU failure - Page 1
Forum section: electronics / repair

author: Pete55
author_rank: Newbie
timestamp: August 27, 2017, 01:35:00 pm
content: After exchanging all electrolytic caps inside the SPU without getting it back to work I finally gave up.This is just a standard SPU with 5V +/-15V and +12VI have replaced it with a standard Meanwell SPU with 5V and +/15V and another small Meanwell with 12VBoth fit perfectly on top of the chassis. I would be more than happy to give more detils about types of SPU and some pictures.Peter
Repair of a Keysight E3633A Power Supply (new board layout) - Page 1
Forum section: electronics / repair

author: Magnum
author_rank: Regular Contributor
timestamp: August 25, 2017, 03:22:40 pm
content: Hello,in another thread I was looking for the schematics for a Keysight E3633A power supply. It seems Keysight doesn't make them public anymore.It is a unit off Ebay which had Error 631 (System DAC test failed) and 632 (Hardware test failed). I used the schematics of the old layout to understand how this thing works. Keysight put in a new processor, ADC (two channels now) and DAC (four channels). As they have more channels on the ADC and DAC they don't need the multiplexers anymore.The DAC was indeed dead (ADC measured fine the voltage, but setting the voltage and amp didn't work). I made sure that the DAC got power, had reference voltage and was receiving data from the main processor. But all four outputs were dead. As they go through 3k resistors into an opamp it had to be the chip itself.I soldered in a new chip and the unit is working now. But I have the following problems:Switching the unit on after it was off for a couple of minutes causes error 632, but the unit works fine. Switching of and on again gives no error, self test passes fine.With the output turned off the connectors have -150mV and -8mA current.I will calibrate it now to see if that problem goes away.

author: Magnum
author_rank: Regular Contributor
timestamp: August 25, 2017, 04:19:50 pm
content: Ok, calibration fixed the voltage and current problem with output turned off. Now I have to see if Error 632 is gone when the unit is cold.
Manual/Schematic Search - VIZ WP-713 Power Supply - Page 1
Forum section: electronics / repair

author: rfdes
author_rank: Regular Contributor
timestamp: August 26, 2017, 01:05:23 pm
content: Hi -Does anyone have access to a schematic/manual for the WP-713 power supply? I found a schematic for the WP-708, however there are significant differences between the two, I believe.Any help would be appreciated -thanksJim
Agilent U1232A problem - beeper almost silent - Page 1
Forum section: electronics / repair

author: mark41
author_rank: Contributor
timestamp: August 26, 2017, 12:32:21 pm
content: I've got this issue on the U1232A Agilent multimeter. The sound of the beeper is almost silent. I tried to change the piezo element with a new piece but it is still the same. Later I connected the beeper terminals to the oscilloscope. The screenshots are from the Power-On sound melody - with piezo speaker connected and without speaker connected. Probably something went wrong on the PCB, but I need a clue where to start. Thank you very much.Mark
Looking for schematics for Keysight E3633A / E3634A (new board layout) - Page 1
Forum section: electronics / repair

author: Magnum
author_rank: Regular Contributor
timestamp: August 24, 2017, 11:37:01 am
content: Hello,I purchased a very good looking Keysight E3633A which doesn't work. I have the service manual for the E3363A, but unfortunately they changed the board layout (switched to 3,3V processor, new ADC and DAC, etc).The basic operation seems to be the same, and I *think* I found the defect, now I have to wait for parts to check it out.Having the right manual / schematics would make things much easier if something else is wrong with the unit.So does someone have schematics for the new board layout?Thanks,Magnus

author: Samogon
author_rank: Frequent Contributor
timestamp: August 25, 2017, 02:42:24 am
content: I bet there is none in public access. Since E3631 has full service manual, rest is missing i gave up finding schematics. Corporations want you to buy new or use their repair service. Unfortunately Keysight is one among many.

author: Magnum
author_rank: Regular Contributor
timestamp: August 25, 2017, 02:55:19 pm
content: Thanks for the reply.First error (was the DAC) is fixed, now I might have another problem. I'll post the problem in a new thread with the correct headline.

author: ruairi
author_rank: Frequent Contributor
timestamp: August 25, 2017, 05:50:25 pm
content: Manuals.lib has the older version service manualwiththe schematicshttps://www.manualslib.com/manual/872509/Agilent-Technologies-E3634a.html

author: Magnum
author_rank: Regular Contributor
timestamp: August 25, 2017, 06:17:21 pm
content: Thanks, I already used this manual to repair the unit.

author: ruairi
author_rank: Frequent Contributor
timestamp: August 25, 2017, 06:32:38 pm
content: Sorry, misread your original post! I have a dead 3634 but it's missing a board, I need a second unit to get things up and running.
Looking for Schlumberger Enertec 5224 oscilloscope manual and schematics - Page 1
Forum section: electronics / repair

author: jloupdef
author_rank: Newbie
timestamp: August 25, 2017, 09:00:48 am
content: Hi,I bought a non working Schlumberger Enertec 5224 oscilloscope, hoping to repair it.I am going to open it for cleaning and inspecting if anything is visually broken.I am seeking forservice manual and/or schematics.Already have the user manual which can be found online (47 pages in french), but it is not enough for serious repair.Anyone with anything would be an amazing help !PS: I know i need be cautious when opening it because of high voltage.Thank you all !
Dead Brother DCP-115C printer control board - Page 1
Forum section: electronics / repair

author: rihardsppl
author_rank: Newbie
timestamp: August 24, 2017, 09:20:59 am
content: My old trusty Brother printer refused to show any signs of life on the control panel, although tests revealed that the main controller PCB is fully functional, I have narrowed down the search to this chip, have tried for hours to identify it, with no avail (See image). Help of any kind would be greatly thanked!Attached is image of the presumably faulty chip and image of the unit that is not functioning (the unit itself and its pcb from both sides)

author: Geerant101
author_rank: Contributor
timestamp: August 24, 2017, 08:45:37 pm
content: For a second there I thought the board was covered with PCB mount fuses but they appear to be jumper wires on the back of the PCB with white silkscreen on the top.I'm not sure what the chip is but it looks like it might be available from Alibaba:https://m.alibaba.com/product/60396135724/LG6154PNL9-TSSOP-30.html?spm=a2706.7843667/c.1998817009.4.vmDzauSent from my SM-G920I using Tapatalk

author: Whales
author_rank: Super Contributor
timestamp: August 24, 2017, 10:19:32 pm
content: Given the exposed metal tab out the end, my first thoughts were 'small motor driver', but this does not fit with its location.

author: sleemanj
author_rank: Super Contributor
timestamp: August 24, 2017, 10:28:26 pm
content: I think from memory that is just silk marking, not an exposed tab.I would fully expect it to be a custom microcontroller or similar, it will be interpreting the key matrix, and driving the LCD at a minimum. At best any replacement will be salvaged from another printer, if you do it yourself or if some fellow in China does it in a back alley, at worst the replacement will be some random chip with re-printed markings.I would advise to just give up on repairing it, it's not worth the trouble, strip the printer down for parts - motors, rods, encoders, gears, the power supply, you can even use that LCD if you really wanted (the BroLCD arduino library even exists, I am pretty sure I used an old single line DCP-115 LCD with it once). It's worth a lot more in it's useful components than it is as a faulty printer, or even as a working printer.
That MHS-5200A function generator - Page 1
Forum section: electronics / repair

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2017, 01:55:58 pm
content: Got one a few months ago. Seemed to work, so I stored it for future use.This morning, the display lights up but no characters appear.Voltages seem to be present inside next to the regulators. The STM processor has power, but scoping the oscillator I didn't see anything, it's a 16MHz crystal. I'd expect to see something there, no?Is there a known defect here? I've looked and not found anybody mention that it just stops working.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: August 24, 2017, 03:25:19 pm
content: Usually there should be something resembling a square wave at th crystal, but I found out that some processors that are advertised as low power do not show any activity at the crystal when probed with a passive scope probe.More telling is if there's something happening at the other pins.Also check the power-pins. If there's basically no noise, then the chip isn't working properly (no switching noise from the processor).What are the lights and buttons do? Is there a signal present at the outputs or at the input of the relays?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2017, 10:22:27 pm
content: Thanks, for now it's back in the box. I'm starting to re-think my "cheap Chinese test gear" philosophy.I might have to go back to "crusty long-obsolete 1960s stuff full of tubes and weird ICs".
Denon AVR-X500 repair! - Page 1
Forum section: electronics / repair

author: hamid.ilyas
author_rank: Newbie
timestamp: August 27, 2017, 01:47:34 pm
content: Hello Guys,So my Denon AVR-X500 AV receiver started giving me weird problems like no sound from some of the channels and intermittent video display problem and then suddenly it died on me about a month ago.It would turn on, do a system check and with a sound of a TICK, it would turn off itself with red blinking light. This was probably because of the safety circuit on board. Anyway, since I am not of a technical guru when it comes to electronics, I gave the set to someone for repair.The guy worked on it for quite some time (around two weeks) and then told me that one of the IC is faulty on the HDMI digital board. He took out the IC and the set came back to life but now there's no sound. The IC is CIRRUS LOGIC CS42528-CQZ which is a DAC as well as S/PDIF converter. This IC is not available in Pakistan and I would most probably be required to import it from either China or Dubai.Now the receiver is giving display, and all of the menu options are working, but no sound. even when I try to do the test tones. What I want to confirm from the gurus is that whether this kind of thing would happen i.e. no sound if you remove this IC from the board? even no test tones?I think I can get the IC quite easily from abroad but if this is something not confirmed, I might prefer to import the complete HDMI board. I would also request you to provide suggestion on where to can get this board?Sent from my iPhone using Tapatalk
Broken Scope CRT - dots everywhere - Page 1
Forum section: electronics / repair

author: szeloof
author_rank: Newbie
timestamp: August 23, 2017, 08:08:02 pm
content: Hi all,As seen below I have a Leroy scope with what appears to be a broken crt or driving circuitry (low voltage?). The display is dim with the grid lines barely visible, mostly made up of dots that flash rapidly and move around the screen (no one part of the screen always stays lit except the weird streaks in the center, other than it looks like its snowing...)Any advice on how to repair would be greatly appreciated. Thanks so much!

author: szeloof
author_rank: Newbie
timestamp: August 23, 2017, 08:09:04 pm
content: I should mention that the scope seems to respond to front panel input (AC/DC coupling leds change, etc.)

author: edavid
author_rank: Super Contributor
timestamp: August 23, 2017, 10:54:22 pm
content: There's no reason to think the CRT is broken.This is arastervector CRT monitor, driven from a frame buffer. Could be asyncproblem with the monitor, or a frame buffer problem, orYou really need the service manual and a working scope to fix this.

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 24, 2017, 05:54:24 am
content: Have you checked all internal supply voltages?

author: niekvs
author_rank: Contributor
timestamp: August 24, 2017, 01:15:38 pm
content: Quote from: edavid on August 23, 2017, 10:54:22 pmIf this is indeed a raster driven by a frame buffer, I would suspect the CRT or driving circuitry, not the frame buffer or anything digital, because if you look at the pattern (or lack thereof) on the display, you can see streaks of phosphor lighting up,seemingly not fitting into a regular raster.

author: grumpydoc
author_rank: Super Contributor
timestamp: August 24, 2017, 01:32:17 pm
content: I thought that the 9400 used a vector display.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 24, 2017, 01:37:38 pm
content: Is there a horizontal hold in the back maybe?

author: StillTrying
author_rank: Super Contributor
timestamp: August 24, 2017, 02:05:47 pm
content: Magnetic deflection vector graphics system 1024 x 1024 addressable points.Schematics appear to be on here:http://www.schematicsunlimited.com/l/lecroyOther than checking a few power supply voltages I wouldn't know where to start!

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: August 24, 2017, 03:42:04 pm
content: The dots look defocused and astigmatic. Might be an issue with CRT drive voltages, or could the scan coils have slipped back along the neck?Not that if it's colour then you should not disturb the scan coils needlessly as realigning them is a tricky job. If they're obviously loose though then that's your fault.

author: edavid
author_rank: Super Contributor
timestamp: August 24, 2017, 05:52:06 pm
content: Quote from: IanMacdonald on August 24, 2017, 03:42:04 pmThey look fine to me, considering the intensity is cranked all the way up.QuoteIt's monochrome.
Satlook buzzing no display - Page 1
Forum section: electronics / repair

author: gilly
author_rank: Newbie
timestamp: August 19, 2017, 06:32:18 pm
content: Hi , I have a satlook perfect 10 which is similar to the mark 3 and when i plug it in, it is making a loud buzzing sound and no picture. I tried it on battery only and the same thing happens.Please let me know if anyone has any ideas on what the problem might beThanks,Gilbert

author: Cyberdragon
author_rank: Super Contributor
timestamp: August 19, 2017, 09:32:17 pm
content: Probably the flyback circuit for that CRT.

author: gilly
author_rank: Newbie
timestamp: August 19, 2017, 11:42:47 pm
content: Thanks for the feedback I will check it tomorrow

author: gilly
author_rank: Newbie
timestamp: August 24, 2017, 06:50:35 am
content: Quick updateI checked all components in the flyback circuit as wellAs on the main power supply and all appear to be OKI noticed though that if I power up the unit on battery only,The display comes on with the buzzing sound still onAnyone else have any other ideas of where I should lookThanks againGilbert
Need help troubleshooting Melzi 3D printer controller - Page 1
Forum section: electronics / repair

author: CharlieWorton
author_rank: Regular Contributor
timestamp: August 24, 2017, 05:57:14 am
content: Yeah... this one is kind of a hail Mary pass, but I figured I'd try it.I bought a replacement electronics board and display controller for my 3D printer, after the original board died. The board I bought is this one:https://www.aliexpress.com/item/BIQU-New-3D-Printer-MELZI-Motherboard-Reprap-MKS-MELZI-Controller-MainBoard-2004LCD-Board-For-Prusa-I3/32760696867.htmlGot it all hooked up, plugged it in, got a red LED beside the power in port... and nothing else. Dead display, no activity when I rotate the controllers or push the reset button on the board.Checked the polarity on the 12VDC in power (it was correct) and tried it again. Same result. Disconnected everything except the power in, got the same result. There are two fans controlled by the board, and one should be spinning constantly. It was dead.So I don't know where to go with this. I tried contacting the retailer, but they haven't had the courtesy to respond. MKS doesn't really have an English component on their website, and certainly nothing resembling a help section.So, crap.Anyone have any thoughts?Thanks - Charlie
Repairing a LifeFitness Elliptical Board (SM8958AC25P (8052 Derivative)) - Page 1
Forum section: electronics / repair

author: Toadlips
author_rank: Newbie
timestamp: August 23, 2017, 09:39:10 pm
content: Good evening all,I'm very much a newbie to electronic circuit troubleshooting, but I'm willing to learn enough to become a comfortable hack. I have a LifeFitness Elliptical machine, and the console starts acting crazy after it's been on for a few minutes. By crazy, it "acts" like a key on the membrane keyboard is stuck down because it beeps as if a key were pressed when no keys are being pressed. It seems like the down arrow is being held down because it flips through the program options. If I press the up arrow, then the scrolling of the options will stop.So, my first inclination was to pry the membrane keypad apart and put a piece of plastic over the contact pad for the down arrow, but that had no effect so I removed the plastic pad. Indeed, when I do a continuity check on the pins coming from the keypad, each key appears to work properly, including the down arrow. So I'm thinking my problem may be elsewhere.The service manual says that when the console board starts acting strange, then it's probably the "memory or the clock". Now, this thing has an SyncMOS SM8958AC25P (8052 derivative) microcontroller, and I had a fantastic idea that I would get a universal programmer for this chip and get the program off of it in case the microcontroller was starting to flake out. I tried that, but when I read all 32K of memory, it's all zeroes...not "blank", but zeroes. Does anyone know if that chip somehow prevents the reading of the program? I "assume" that the program is stored in that flash RAM.Now, there is one hitch. Connected to pins 7&8 (SPWM channels), is an EEPROM AT24C02. Is it possible that that EEPROM is actually holding the program for the microcontroller? Would the microcontroller "know" to look to that external memory to get its program if there is nothing to tell it to do so in the flash RAM included with the microcontroller? Also, there is a crystal connected to the clock pins...should I be looking at that?Yes, I realize that I have two different agendas: 1) just fix the thing and 2) get the program so that I'll be able to repair this thing in the future if the microcontroller gets fried...if it's possibleThanks for any pointers!
MGL Avionics VHF Radio repair - Page 1
Forum section: electronics / repair

author: steve_w
author_rank: Regular Contributor
timestamp: August 22, 2017, 10:29:06 am
content: Can anyone identify the component with the hole in it? I am repairing an MGL Avionics VHF Transceiver from my brother's gyro copter.MGL have discontinued this model so I think manufacturer support is unlikely, but i'll try.My brother was charging the battery on his gyro, all plastic construction, with the radio on, yeah I know! pilots WTF.The component is either in series with or hanging off the 12V supply line.Any advice or circuits would be appreciated.regardsSteve W

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 22, 2017, 11:46:28 am
content: Does the top line say GGK? if so, 60V TVS:https://www.diodes.com/assets/Datasheets/ds19003.pdf

author: steve_w
author_rank: Regular Contributor
timestamp: August 23, 2017, 08:52:27 am
content: Thanks your answer is spot on.I identified a replacement at element 14 for the princely sum of 6 cents pity about the 25 bucks for delivery :-(regardsSteve W
Sencore PA-81 manual - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: August 22, 2017, 10:29:16 pm
content: Just acquired a Sencore PA-81. Does anyone have any info on this piece of test equipment? I am looking for a service manual and owners manual.Thank you for any help.Chuck

author: Toasty
author_rank: Regular Contributor
timestamp: August 22, 2017, 10:47:46 pm
content: My Google-fu only shows PAID versions in paperback available. $25-$30Even on Amazon! lolT

author: Bargainhunter
author_rank: Regular Contributor
timestamp: August 23, 2017, 12:34:37 am
content: wow.

author: Toasty
author_rank: Regular Contributor
timestamp: August 23, 2017, 01:45:45 am
content: Try contacting Sencore through their tech support. They might just send you a schematic.http://www.sencore.com/procare-support/service-repairThere are phone numbers on that page, might be worth a ring first.T

author: Toasty
author_rank: Regular Contributor
timestamp: August 23, 2017, 01:59:07 am
content: Also, do a search on eBay for "Sencore PA81". When you get the results page, scroll down and on the left and click on "Sold listings".A few listings down (probably you at the top) is a seller with a listing for "14 Sencore Manuals, 6 Catalogs on CD - SG165, SG80, PA81, TF40 manuals schematic"In the listing description it reads "PA- 81 Stereo Amp Analyzer – Instruction Manual "Operation, Application and Maintenance", Schematic and Parts List + the Application / Training Notes - "Sencore Tech-Tips - #179" - "Learning to Use the PA-81" (BOTH ARE HARD TO FIND)".He sold what he had, but you can do a "Contact the seller" via his eBay page. He might be able to create a new one for you.For $12.99 it's worth a shot.T
Toshiba LTM08C015KA LCD datasheet and reverse engineering - FPGA VGA output  - Page 1
Forum section: electronics / repair

author: adilmalik
author_rank: Contributor
timestamp: April 24, 2017, 10:16:06 am
content: Hi Everyone,Recently I posted about fixing my HP 54542Cs LCD, turned out to be something simple in the end. Due to the nature of the damage, I dont know how long the LCD will last, so I want to reverse engineer the protocol and add a custom FPGA based VGA output. This way I can also support other LCDs if this one dies.The LCD in question is a toshiba LTM08C015KA. This is used in the HP54542C and the Anritsu MT8801B Spectrum analyser. Unfortunately, I cannot seem to find a data sheet for it. At first glance it looks like a 18-bit RGB protocol. Does anyone have more info or a datasheet for this lcd?

author: marshallh
author_rank: Unknown
timestamp: April 25, 2017, 02:40:34 am
content: Very easy as long as you have a working example. Get a multichannel logic analyzer and tap everything while it runs. Once you find the digital RGB lines you can ignore all but a few of those, and focus your efforts on the control signals. Either it'll be Hsync/vsync controlled, or DE only.You could also use a FPGA with Signaltap based on the display's pixel clock to capture exact timings.

author: Testtech
author_rank: Regular Contributor
timestamp: August 20, 2017, 08:25:51 pm
content: It too have an HP scope using this display. Any progress on this retrofit?

author: Rasz
author_rank: Super Contributor
timestamp: August 22, 2017, 11:02:58 pm
content: might be similar to this onehttp://html.alldatasheet.com/html-pdf/143915/TOSHIBA/LTM08C351/1202/4/LTM08C351.html
Looking for Display Schematic for Agilent E3620A Power Supply - Page 1
Forum section: electronics / repair

author: ArcticGeek
author_rank: Regular Contributor
timestamp: August 21, 2017, 01:48:11 pm
content: Hello all,I purchased an Agilent E3620A power supply from our favorite auction site recently. I'm looking for the schematic diagram of the voltmeter/ammeter display assembly for this unit. I've found the schematic for the power supply in a few spots on the web (including this site!)....but I haven't found a schematic for the voltmeter/ammeter assembly. Does anyone know where I might find this?The unit works fine with the exception of the voltmeter display. The voltmeter works fine from 0V up to 19.99V, but once it switches to the higher range above 20.0V it goes wonky. Once it goes above 20.0V, the voltmeter fluctuates between the low range and high range, and flashes back and forth. Once the voltage is above ~21.5V or so the high range finally locks and the it works okay. But right around 20.0V - 21.0V the display is not usable. The power supply output is actually fine, no oscillations or anything weird if you look at it on a scope or if you connect a multimeter to the output. When lowering the voltage from high voltage (say 25V) downward, the range switch takes place right at 18V like it is supposed to and works good. But the range switch going up has a problem.I suspect that the TC14433 voltmeter IC is faulty, but I'd like to find a schematic of the display section to verify this. I have found sample schematics for that IC on the Microchip website, but all of the sample schematics I've found do not have the autoranging feature.Anyone know where I might find a schematic?

author: JoeO
author_rank: Frequent Contributor
timestamp: August 22, 2017, 03:11:10 am
content: Here are some previous places the schematic was discussed. No one indicated that they were successful in finding the schematic for the display.https://www.eevblog.com/forum/testgear/schematic-for-agilent-e3630a/https://www.eevblog.com/forum/repair/agilent-e3614a-repair/

author: ArcticGeek
author_rank: Regular Contributor
timestamp: August 22, 2017, 04:31:48 pm
content: Thanks JoeO.I had already found those other posts, but nowhere I have seen any proof that anyone actually had the schematic for the display board. A few people have indicated that they had it or had seen it, but I have not been able to find the actual schematic anywhere.I have also PM'd a couple people who indicate they have the schematic, but so far no response.
About Dell Vostro 1500 battery - Page 1
Forum section: electronics / repair

author: hispeck
author_rank: Newbie
timestamp: August 21, 2017, 05:32:38 pm
content: Hi, i have a dell vostro 1500 battery type fk890 that is fully charge but cant power the laptop, when i open the battery i discovered that there was no voltage output on any of the 9 terminals, but the battery has 11.1v, i think the fault is in the battery circuit board. any help on how to fix it?Hispeck

author: Zucca
author_rank: Unknown
timestamp: August 22, 2017, 10:29:27 am
content: replace the battery with a new one?
Help identifying this cable please?  - Page 1
Forum section: electronics / repair

author: Specmaster
author_rank: Super Contributor
timestamp: August 24, 2017, 01:36:11 pm
content: Hello, I love to try and repair older style test equipment and one that I'm working on is a Hameg 408-1A scope and it uses loads of this type of cable in both 3 and 6 cores as per photo. I thought it would be described as ribbon cable but on searching for ribbon I keep find the multicolored flexible kind which is not the same thing at all.The cable I'm looking is solid cores and has to pushed into self gripping sockets have a push to release the cables mechanism. The cable on my old scope has been disconnected so many times now that the cores are fracturing and also because of that, it has been cut back and restripped that the leads are not really long enough now either.

author: stmdude
author_rank: Frequent Contributor
timestamp: August 24, 2017, 06:14:03 pm
content: I have no idea what the proper name is, but a lot of people seem to call it "ribbon jumper cable".Example source:https://www.allelectronics.com/index.php?page=seek&id%5Bm%5D=pattern&id%5Bq%5D=ribbon+jumper+cable

author: Specmaster
author_rank: Super Contributor
timestamp: August 24, 2017, 06:28:57 pm
content: That certainly looks like it apart from its got more cores then I need and the other really big problem, I need long lengths, some maybe about 500mm.

author: JFJ
author_rank: Regular Contributor
timestamp: August 24, 2017, 06:53:24 pm
content: This looks similar:http://uk.farnell.com/molex/882060016/ribbon-cable-idt-6way-per-m/dp/1313458

author: stmdude
author_rank: Frequent Contributor
timestamp: August 24, 2017, 07:05:32 pm
content: Found it on DigiKey as well. Big selection:https://www.digikey.com/products/en/cable-assemblies/flat-flex-ribbon-jumper-cables/457?k=&pkeyword=&pv321=116&FV=ffe001c9&mnonly=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25Unfortunately, their longest (457 & 558mm) are out-of-stock with a few week lead-time. However, it seems like it's Molex parts, so maybe some light googling on their part#s might yield an alternate source.
CAVITRON BIOSONIC US100 - Page 1
Forum section: electronics / repair

author: quinoara
author_rank: Contributor
timestamp: August 20, 2017, 01:25:09 am
content: Dear foristas: I have under repair a SCALER ULTRASONIC PIECE (CAVITRON) equipment for dental use WHALEDENT MODEL BIOSONIC US100. The defect is that the handpiece does not work.In the routine review only 12V are present to feed the ICs. When activating the pedal it feeds some MOSFET transistors with 42V and there is not presence of any type of oscillation in any component.Diodes, resistors, coils, mosfets and the coil of the handpiece were checked and found normal. They changed all the integrated and remains the same.I have searched the internet for the scheme of this equipment and I do not find it. Make a basic outline of IC 34063AP1 which I suspect, but I can not interpret it, I request some guidance in a timely manner, thank you in advance for any comments.The Cavitron in particular has the following integrated:34063AP1 replace it with the MC34063CD40106BCNLM2907CD4027BCN

author: amyk
author_rank: Super Contributor
timestamp: August 20, 2017, 03:39:58 pm
content: Yes, the 34063AP1 is the standard 34063 SMPS controller.
Why did my new Hisense 43 inch TV fix itself after 12 days ? - Page 1
Forum section: electronics / repair

author: ez24
author_rank: Super Contributor
timestamp: August 21, 2017, 12:07:03 am
content: HiOn Aug 2, 2017, I bought a 43 inch Hisense TV (because it has 3 USB ports). When I turned off the TV, it would come back on aut after 20 seconds. Then it took me 10 seconds to turn it off again and it would NOT come back on by itself (the second time). The TV had to be warmed up for this to happen. This would not happen to it when cold.I got the last one at Costco and I waited almost 2 weeks to see if they would get another one and they did not. But other Costco's in the area have them so I was going to return it and get another one. The night before I was going to return it, the TV did not come back on.For a week now it has worked OK (stays off). How and what happened? How could it fix itself? The TV is not connected to the internet nor cable, just an antenna. There are no firmware updates.BTW technical help had me do resets that did not help. They said they never heard of this problem and the TV had to be returned. My guess it was a "whisker" in a logic circuit that disappeared after 12 days.TIA

author: RoGeorge
author_rank: Super Contributor
timestamp: August 21, 2017, 12:30:08 am
content: Maybe the TV has Wi-Fi and updated itself, or maybe you have a neighbor with a remote that interfere with your TV.It could also be because of dried/bulged/leaked capacitor. Temperature variation, or simply just the passing of time, can make the defect hard to reproduce.Replace it if you can.Even better, return it if you can.TV is really, really bad, a real life damager.

author: Electro Detective
author_rank: Super Contributor
timestamp: August 21, 2017, 12:32:19 am
content: Perhaps it tried to check for updates as some TVs do during long switch off periods at night, and it went south ?I had to dig deep into the menus on my Panasonic to disable this annoyance.If it happens again and you suspect a whisker, blow some air into the vents if possible with a vac in reverse and some light tapping etc, you may get luckyWorst case, take a video when it exhibits the bad behaviour as 'proof' for when you return it,otherwise you know the deal with that
UNI-T UT210E Problem - Page 1
Forum section: electronics / repair

author: HolidayBob
author_rank: Newbie
timestamp: August 16, 2017, 08:34:05 pm
content: Hi all, I have a UT210E which I bought from Asia a few months back. I have noticed that the AC/DC voltage it's way out. All the other ranges OHMs, current etc are working spot on. I have tried to do a re-calibration by holding down the Blue/Yellow buttons and switching on, it goes through and returns ERROR 0 which I assume is correct. So my question is are there any trimmers inside the unit I can adjust to sort out the voltage problem?I look forward to any help anyone can give.HB.

author: MosherIV
author_rank: Super Contributor
timestamp: August 17, 2017, 08:34:24 am
content: HiWelcome to the EEVBlog forum.There are no trimmer pots in the UT210E for calibration. The calibration is held in EEPROM.Details can be found in this threadhttps://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/375/

author: HolidayBob
author_rank: Newbie
timestamp: August 19, 2017, 06:53:30 pm
content: Hi MosherIV, Sorry for the very late reply and thanks for the reply and welcome. So if there is no way I can fix this easy looks like I will have to put up with it. I just checked a voltage fro my bench power supply which is set to 9V DC, measured on the 210E it reads 11.78V dc!HB