hybridfree/eevblog-posts huggingface dataset:
U3641 advantest Spectrum analyzer. - Page 1
Forum section: electronics / repair

author: Ken121
author_rank: Newbie
timestamp: March 06, 2019, 03:17:08 pm
content: Thank you for any and all help.

author: tggzzz
author_rank: Super Contributor
timestamp: March 06, 2019, 03:29:44 pm
content: Quote from: Ken121 on March 06, 2019, 03:17:08 pmWithout more information, I suggest you try Advantest.Alternatively, have a look athttps://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/Failing that, if you look elsewhere on this forum then you will see that replacing the electrolytic capacitors solves many problems

author: SpencerTC
author_rank: Contributor
timestamp: March 06, 2019, 04:32:53 pm
content: Well, without knowing a little more, there is little anyone can do.....you can't fix a problem that you have no information about.What is wrong with it? Will it turn on? Is there any obvious physical damage (evidence of impact/water/overheating)?What have you tried so far? Have you disassembled the instrument yet? Did you notice anything out of the ordinary when you looked in it (eg. vented electrolytics)?Have you searched the web for common issues with this particular model? Have you searched for the service manual?Do you have any experience repairing electronics at the component level or are you just asking if it's possible to just swap a module out and call it fixed?Next time you make a topic, I would recommend you explain whatever it is about a little more. People can't help (and often won't want to) if they don't know anything about the issue (or about you or your reasons for wanting to do what it is you're asking)Good luck!
help with 220v AC motor - Page 1
Forum section: electronics / repair

author: alah
author_rank: Contributor
timestamp: February 27, 2019, 04:00:55 pm
content: I have an AC motor, 220v, 1 ph. What if I power it with 220v, 2ph? Any problem?Its a mixed air blower, what does the SP meanin the specs?" 260cfm at 1.2in. SP "Thanks, Alberto.

author: duak
author_rank: Super Contributor
timestamp: February 27, 2019, 05:43:25 pm
content: Alberto, what do you mean by 220 V, 2 phase?Do you mean 220 V, with a neutral connection as well as the two line connections?Cheers,

author: eKretz
author_rank: Frequent Contributor
timestamp: February 27, 2019, 06:59:20 pm
content: 260 CFM at 1.2" Static Pressure.

author: Gregg
author_rank: Super Contributor
timestamp: February 27, 2019, 07:12:39 pm
content: SP means Static Pressure; 2 in. means 2 inches of water column. In other words when the fan is working in nominal conditions, the outlet pressure can be 2 inches of water pressure higher than the inlet side without overloading the motor. If you have a long duct on the outlet with some turns, it may give enough flow resistance that the fan motor could be overloaded which isn’t likely if you are just blowing soldering fumes outside. Restrictions on the inlet, like a partly clogged filter, will generally cause lower motor load as the fan itself is operating in a partial vacuum in such cases. Of course there are some exceptions.I’m not familiar with Venezuela electrical systems but if you have 220 volts potential and neither motor lead is referenced to ground, you should be OK if the frequency is suitable and the amperage is available. You could always try the “dim bulb” test with a fairly high wattage incandescent light wired in series with your motor for testing purposes. Please be safe

author: alah
author_rank: Contributor
timestamp: March 02, 2019, 02:22:17 am
content: It does have a groun lead, but its connected to the casing ( body ), so I think I'll be ok. I'll try tomorrow, thanks.
Xantrex XRF 60-20 PSU - Schematic or block diagram? - Page 1
Forum section: electronics / repair

author: Tracker
author_rank: Regular Contributor
timestamp: February 23, 2019, 09:11:11 pm
content: Hi Folks,I have saved a Xantrex XRF 60-20 from the dumpster.Anyone got a service manual / schematic or even block diagram of these XRF PSU's?I did an inspection and found a blackened Tantilum 10uF 25v cap on the input to a to LM317T (located close to where the fans are connected), so replaced that hoping that was the only issue.Power it up to see front panel display was flashing up '1' in both Amps and Volts followed by some random numbers.And fans were not running.After about 30 seconds there was a little puff smoke from a UF4004 diode which feeds the input to LM317T.The diode read less than 20 ohms so I suspected the shorted Tant had triggered the diode to fail, so I replaced the diode with a 1N4007 (which is all I had).On the next power up, all looked good!Front panel came up with a steady '0' and '0' (pots were turned down) and the fans were running... so progress, or so I thought.Within 30 seconds the previously replaced diode popped open and literally broke itself in two parts while also melting the solder on its pins!Oddly there is no other sign of overheating, nothing downstream looks baked or fried.I'm suspecting the LM317T is responsible but it's not shorted.So before I go any further a schematic would be really helpful, even if just to see what the LM317T is feeding etc.ThanksTracker

author: coromonadalix
author_rank: Super Contributor
timestamp: February 23, 2019, 09:55:44 pm
content: thoses xantrex psus never had any leaked schematics to my knowledge, ask Xantrex / Sorensen

author: Tracker
author_rank: Regular Contributor
timestamp: February 23, 2019, 10:29:33 pm
content: Thanks,I emailed them during the week but got nothing back yet.They seems a secretive lot.Tracker

author: factory
author_rank: Super Contributor
timestamp: February 24, 2019, 11:21:42 pm
content: If you can figure out the equivalent Glassman model, try asking them too.David

author: coromonadalix
author_rank: Super Contributor
timestamp: February 25, 2019, 02:22:56 am
content: I think there is an equivalent in TDK too ?? not too sure TDK / Lamda ??

author: Tracker
author_rank: Regular Contributor
timestamp: February 28, 2019, 09:26:45 pm
content: Yes thanks , the Gen 60-25 from TDK/Lamda is quite similar.I will try them.CheersTracker

author: Tracker
author_rank: Regular Contributor
timestamp: March 01, 2019, 12:58:48 pm
content: Good news, PSU is repaired.Replacing the LM317 regulator restored normal operation.Nice PSU, well designed and nothing but the best of parts used!CheersTracker
What are these LEDs called & where can I buy? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: February 23, 2019, 08:38:30 pm
content: Please see attached photos for this blue panel LED that has a sort of molded in 'light pipe' to carry the light thru the front panel.I've seen these for years but I do not know what they are called, so it's hard to do a search. Anyone know if this style has a formal name (or names)?I've included one photo of a similar red LED, from the same unit, for reference.Know of a US source for small quantities? Thanks...

author: SMdude
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:17:24 pm
content: What is the diameter of the bit that pokes through the panel?

author: pbarton
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:28:53 pm
content: Try searching for "Through Hole Leds" and look at Google images.

author: tsman
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:31:32 pm
content: Through-hole Tower LED e.g.https://uk.farnell.com/multicomp/mcl223gd/led-2mm-60-green/dp/1581106

author: jfiresto
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:34:01 pm
content: Trycylinder LEDs at Kingbright

author: cvanc
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:42:51 pm
content: Quote from: SMdude on February 23, 2019, 09:17:24 pm2mm.The total height of the molded part is about 5mm.Thanks.

author: eb4eqa
author_rank: Regular Contributor
timestamp: February 24, 2019, 12:10:40 am
content: Look for 2mm led in eBay. There are many, and cheap. Roberto

author: scl
author_rank: Contributor
timestamp: February 24, 2019, 12:35:23 am
content: They are called "taper body" LEDs.Digikey has red and green:https://www.digikey.com/product-detail/en/lumex-opto-components-inc/SSL-LX20465ID/67-1125-ND/270923https://www.digikey.com/product-detail/en/lumex-opto-components-inc/SSL-LX20465GD/67-1127-ND/270925Blue I did not find, other than a mention of a "super-blue" being a special order from the factory.

author: cvanc
author_rank: Frequent Contributor
timestamp: February 27, 2019, 01:09:05 pm
content: Thanks everybody. It seems that finding a blue LED in this form factor is the challenge.I actually reached out to the manufacturer of the product this LED is in and to my surprise they agreed to send me a replacement.

author: stj
author_rank: Super Contributor
timestamp: March 01, 2019, 11:38:19 am
content: Quotedrag your mouse over the link, dont click on it.now you have some part numbers

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 01, 2019, 11:55:25 am
content: That link will not load for me, but at the momentthis onewill.

author: stj
author_rank: Super Contributor
timestamp: March 01, 2019, 12:53:49 pm
content: repaired it, the forum software chopped the end off!--o.k. i give up, this shit forum software insists on fucking the link!it totally ignores things being in quotemarks and screws them up anyway.
Can I get a one-off PCB made cheaply? - Page 1
Forum section: electronics / repair

author: billbyrd1945
author_rank: Regular Contributor
timestamp: January 23, 2019, 04:37:59 pm
content: I've been working on a wine cooler for a couple of months now taking off components and putting them back on. So the pads and traces have taken a beating. Is there any one out there who makes replacement boards cheap enough for the hobbyists? I have searched Google, but haven't found such a source so far. Thank you.

author: ArthurDent
author_rank: Super Contributor
timestamp: January 24, 2019, 03:54:52 pm
content: It's not a pretty fix but where a lead goes through a hole with a lifted pad, instead of cutting the lead short you could scrape the resist off the run and bend the long lead to lay on top of the run. Then run solder along the length of the lead from where it comes through the pad to the end of the lead. If an entire run has lifted you can use an insulated wire jumper to replace the run. I've had to do this a few times. I don't think getting another circuit board made is realistic but perhaps finding another used replacement board is a slight possibility.

author: billbyrd1945
author_rank: Regular Contributor
timestamp: January 24, 2019, 04:19:52 pm
content: Thanks Arthur.

author: deskpro256
author_rank: Contributor
timestamp: February 28, 2019, 08:49:46 pm
content: Also, if the PCB isn't too complex, you could try reverse-engineering it, draw a schematic and trace a PCB yourself. Then order it from some cheap prototyping PCB house like JLCPCB, PCBWay or many others, look them up. Or try etching one yourself if you're up to a weekend challenge.That way you would have some spare boards already made for future problems or anyone else with the same problem could get your PCBs.

author: amyk
author_rank: Super Contributor
timestamp: March 01, 2019, 02:39:13 am
content: Quote from: deskpro256 on February 28, 2019, 08:49:46 pmThis. Also don't forget to share the results on the Internet with us.

author: billbyrd1945
author_rank: Regular Contributor
timestamp: March 01, 2019, 03:03:48 am
content: Will do. Thanks for the responses.
Dash cam repair/component ID request - Page 1
Forum section: electronics / repair

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: February 27, 2019, 06:01:42 am
content: Hey,Generic brand dash cam was fed with vehicle ACC+ instead of 5V into the USB mini-B socketSOT-23-6 "LPS 8W8" released the magic smoke - I can't find anything on google as to what it isAppreciate any help

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: February 27, 2019, 06:12:39 am
content: Assuming the silkscreen mark is for pin 1,pin 1 gndpin 2 gndpin 3 vinpin 4 trace leads to unpopulated footprint to the right of this packagepin 5 gndpin 6 gndGoing to try substituting a diode if I can find one to salvage

author: DaJMasta
author_rank: Super Contributor
timestamp: February 27, 2019, 06:14:38 am
content: Don't know if this is a lead, but you can buy similarly marked parts, at least:https://www.aliexpress.com/item/LPS-SOT23-6-SOT363-100-NEW-ORIGINAL/32825111244.htmlSeems like a lot of pins for a diode, but maybe, it does seem like some searches show up with that. Could be a LDO as well. Any others on the board? Could be a lead with how it's used there.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: February 27, 2019, 06:26:50 am
content: No others on the board, definitely looks like the same part and makes sense to be a vreg, was really hoping it was input protection but what can I expect from something mass producedWill have a play with my psu feeding pin 4 to see if there's any sign of lifeThanks for the link

author: fzabkar
author_rank: Super Contributor
timestamp: February 27, 2019, 07:17:05 am
content: https://item.taobao.com/item.htm?id=582236311639The text translates to "Screen printing LPS 8W5S3 8W6S3 8W6S0 8W7F1 SOT23-6 overvoltage protection IC chip".I would remove the IC and install a regular TVS diode in the unpopulated spot next to it (assuming pin #4 is grounded).LP5300B6F, LowPowerSemi, Overvoltage (6.1V) & overcurrent (2.1A) protection IC, 3V - 36V in, marking 8Wywx, SOT23-6:http://www.lowpowersemi.com/uploads/soft/20170926/LP5300.pdf

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: February 27, 2019, 09:05:21 am
content: Seems like the one, thanks a bunch

author: fzabkar
author_rank: Super Contributor
timestamp: February 28, 2019, 12:07:41 am
content: If the dashcam were mine, I would remove the IC and install a TVS diode between pin #4 and ground, and then install a polyfuse in the unpopulated location adjacent to the IC.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: February 28, 2019, 05:01:41 am
content: I bodged in a 500mA polyfuse, confirmed it still worksWill try and find a small enough TVS to salvage, the board has an LCD sitting directly on top of it so its a bit tight in there
EICO Model 460 Oscilloscope at 120VAC - Page 1
Forum section: electronics / repair

author: nexon
author_rank: Newbie
timestamp: February 26, 2019, 05:25:58 pm
content: Got my old EICO Model 460 oscilloscope running, mostly just bad filter capacitors. Here are some pictures of the 'scope in action:EICO 460I'd like to be able to run the 'scope at 120VAC, but the B+ current bothers me. Specifically the wattage on R77.According to the Instruction Manual, Maintenance Section:QuoteThat would be 4W (E^2/R) @45V, and a maximum of 5W @49.5V. OK, I guess: it's a 5W resistor...When I measure the voltage drop across R77 at 115VAC input, I get 50V, at the high end of the acceptable values. Raising the input to 120VAC, the R77 voltage drop goes to 53V, giving 5.6W.At the moment I'm running the 'scope at 110VAC, which gives a 48V drop and 4.6W on R77. Should I just replace R77 with a 10W, and not worry about it?

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: February 27, 2019, 04:19:31 pm
content: Great old piece. Got one a while ago, probably needs a good recap as well.I would replace with a 10W, but also install a carefully selected line fuse of appropriate rating to protect that transformer at the same time. That way, if something starts to draw more current, the fuse might go before damaging something else...
Toshiba laptop L300 backlight - Page 1
Forum section: electronics / repair

author: rfengg
author_rank: Regular Contributor
timestamp: February 27, 2019, 05:40:28 am
content: When my Toshiba L300 laptop is switched on , the display comes on fine for a couple of hours , but completely goes OFF after that.The video display output is allrite since I can see a very faint image on the screen......my guess is that its either the CFL inverter or the CFL itself that's on its way out.Any guesses on which I should replace first.....the inverter or the CFL itself?

author: Rasz
author_rank: Super Contributor
timestamp: February 27, 2019, 09:49:15 am
content: its a crap 10 year old laptop, you could probably buy perfectly fine X220/X230 cheaper than another screen for this toshibabut if you really want to, start with inverter
Slug Bird 43 (100A) Help - Page 1
Forum section: electronics / repair

author: bin10
author_rank: Contributor
timestamp: February 26, 2019, 11:21:23 am
content: Good morning,I received a Slug Bird 43 (100A) as a gift.Unfortunately it does not work perfectly.The Watt AWG reading is perfect, but the Watt PeP reading has gone crazy.I checked the few internal components, Trimmer is OK, Diode is OK, I think the problem is in the fixed value resistance but I do not know its exact value.Thank you.

author: rfengg
author_rank: Regular Contributor
timestamp: February 27, 2019, 05:32:20 am
content: Matey,Sorry but the Bird 43 is designed only for average power ONLY , so you should not be using the 100A slug to make PEP readings on a Bird 43.The meter needle will jump around with the carrier peaks if you use it this way......you need a peak reading kit for PEP or the 43P with the relevant slugs.

author: bin10
author_rank: Contributor
timestamp: February 27, 2019, 07:54:30 am
content: Yes, the PeP Reading Kit is installed and works with all other Slugs.only with this Slug the reading is very different.I have read the PeP USB watt of a RTX under test.all the other slugs indicate the exact measure (50 Watts PeP) while this slug even shows 100 Watts PeP.
Looking for HP 8341A / 8340A Service manual - Page 1
Forum section: electronics / repair

author: Mrt12
author_rank: Regular Contributor
timestamp: February 20, 2019, 10:10:09 pm
content: Dear colleagues,I am looking for the HP 8340A / 8341A Synthesized Sweeper service manual.Not a single copy which can be found on the internet is readable

author: pbarton
author_rank: Frequent Contributor
timestamp: February 20, 2019, 11:04:25 pm
content: If you are prepared to pay for readable manuals, then go tohttp://artekmanuals.com/Satisfaction guaranteed or your money back, no exceptions, no hassles.

author: Mrt12
author_rank: Regular Contributor
timestamp: February 24, 2019, 05:33:36 pm
content: Quote from: pbarton on February 20, 2019, 11:04:25 pmI know, but thank you though. I already have a big collection of manuals from Artek, for all my instruments.However, for the 8341A or 8340A, they don't have the manuals :-(

author: mftaylor
author_rank: Newbie
timestamp: February 24, 2019, 07:21:17 pm
content: Did you try searching on Keysight , they appear to have the manual for the 8340A

author: coromonadalix
author_rank: Super Contributor
timestamp: February 25, 2019, 02:27:40 am
content: Keysight will remove the schematics in the manual ... Artek is the best solution

author: Tony_G
author_rank: Super Contributor
timestamp: February 26, 2019, 06:30:04 am
content: I have the manuals for the 8340/1A I think. I'm on vacation right now in Aus so reply to the thread week of Mar 4th and I can follow up with some scans if you need a specific part of the manual (assuming I have it of course)TonyG
Apple cinema 24" display turning on/off - Page 1
Forum section: electronics / repair

author: maxigor83
author_rank: Newbie
timestamp: February 26, 2019, 05:25:26 am
content: Hi guys, have a known problem with apple cinema 24" with turning display on/off .It's connected to mini dsiplay port to mine win10pc and worked good for while, but when I go higher with brightness more then let's say 50% it starts blinking (turning on off).So I assumed maybe capacitor problem somewhere and I took it apart, and what I notice that on big capacitors (big white ones) on pics below when voltage goes over 64 V it's start blinking!?Any suggestions and ideas, or maybe schematic,boardview for it.Thanks for help!!Poslano sa mog MIX koristeći Tapatalk
does some one have the EFRATOM LPRO-101 schematic ? - Page 1
Forum section: electronics / repair

author: testpoint1
author_rank: Frequent Contributor
timestamp: February 25, 2019, 03:53:28 pm
content: I meet several LPRO 101 can not lock, lamp voltage, VCO circuit seems all OK, I need to check the servo circuit, but no schematic, if someone can share me, I can give you a LPRO-101 (can not lock), hehe.searched "http://www.ko4bb.com/getsimple/", no LPRO circuit, only have the old model's. FRS etc.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 25, 2019, 08:03:15 pm
content: Here's some info. I think I have a link to more complete info if I can find it.http://www.ham-radio.com/sbms/LPRO-101.pdfMorehttp://ftb.ko4bb.com/manuals/65.175.237.176/Efratom_LPRO_101_Repair_Guide.pdf

author: testpoint1
author_rank: Frequent Contributor
timestamp: February 26, 2019, 02:11:41 am
content: thank you, all have, maybe the author of the "repair guide" has the schematic, but have no contact.
Help with "complementary" SCR - Page 1
Forum section: electronics / repair

author: vindoline
author_rank: Unknown
timestamp: February 15, 2019, 03:33:20 am
content: Help, I have a Power Designs TW6050A supply with a non-functioning over-voltage crowbar circuit. Close inspection of the board shows that CR25 let out the magic smoke a long time ago. This is an old GE part number C13F. It's an odd "complementary" SCR. The gate is on the anode side. I found a reference to it in a1977 GE semiconductor data book.I've had no luck finding any information about a replacement. Does anyone have any ideas?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 15, 2019, 07:15:08 am
content: PUT.Any should do, which is fortunate because basically only one exists anymore: 2N6027.Tim

author: vindoline
author_rank: Unknown
timestamp: February 15, 2019, 01:30:25 pm
content: Tim, Thanks so much! Of course they changed the name

author: JoeO
author_rank: Frequent Contributor
timestamp: February 15, 2019, 03:51:43 pm
content: Quote from: vindoline on February 15, 2019, 01:30:25 pmThe GE Semi Data Book link in your first post has a lot of useful information.Thanks for the link!

author: vindoline
author_rank: Unknown
timestamp: February 15, 2019, 05:40:03 pm
content: Quote from: JoeO on February 15, 2019, 03:51:43 pmYou're welcome

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 15, 2019, 05:56:44 pm
content: Hi!There's also a Pro–Electron coded device called the BRY39 that used to be used in the field timebase oscillator stage of early s/s colour TV sets that had both an anode–gate and a cathode gate, you might be able to try this device with a 1k resistor between cathode–gate and cathode (use an ⅛W resistor) to prevent random triggering!The BRY39 shouldn't be too hard to find as vast piles of early solid–state TV sets used it!Chris Williams

author: vindoline
author_rank: Unknown
timestamp: February 16, 2019, 03:01:33 am
content: Quote from: Chris56000 on February 15, 2019, 05:56:44 pmThanks! It's great to have several alternatives. The BRY39 looks to be rarer/more expensive than the 2N6027. I'll give that a try first and report on its performance.

author: vindoline
author_rank: Unknown
timestamp: February 25, 2019, 08:56:05 pm
content: Just to wrap this up, I got the 2N6027 and replaced the blown C13F. The over voltage crowbar is now working fine. Thanks everyone!
release catch for Tek TM503 plug-in needed - Page 1
Forum section: electronics / repair

author: worsthorse
author_rank: Super Contributor
timestamp: February 20, 2019, 06:19:05 pm
content: Good morning, wondering if anyone has a spare release catch for a TM503 plug-in? This is the release that is two parts and slides; I think it is the newer version, photo attached. I'd be happy to get a junker plug-in and take the latch out myself, as long as the mechanical bits are there. The function generator would be especially awesome.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 27, 2019, 02:24:32 am
content: http://www.1sourcecomponents.com/availability/TEKTRONIX--366-1851-01.htmsays they have 6 available. You'll have to ask them the price.On your other thread I have posted an .stl file that will let you print one if you have access to a 3D printer.Or PM me and for $5 I'll print one and send it to you.

author: pbarton
author_rank: Frequent Contributor
timestamp: February 27, 2019, 04:51:32 pm
content: It would help if you provided the specific Tektronix part numbers that you are looking for.However, if you are after a Tektronix 366-1690-00 LATCH release, then there is one on eBay.co.uk.See eBay item number:333082055483, its more than half way down the drop down menu.You may have to ask the seller if they are prepared to ship to the USA. If not, then I will help.Is there another part number you are looking for?

author: worsthorse
author_rank: Super Contributor
timestamp: February 27, 2019, 04:56:08 pm
content: Good morning - Thanks for the offer to help. You are right, I should have tracked down the part number before posting.It looks like I can get a 3D printed replacement, which will work for now. If that doesn't pan out, I will check the part number, look at the ebay listing, and send you a PM.
CIC806 is 100% equivalent  to ICL7126 ? - Page 1
Forum section: electronics / repair

author: PKTKS
author_rank: Super Contributor
timestamp: February 24, 2019, 04:49:17 pm
content: I am having problems finding the CIC806 datasheet.CIC has absolutely no end user support with their chipsets.This old CIC806 chipset may find a use recentlyand I need to make sure it is 100% compatible with ICL7126 chipsAny hint or even the datasheet welcomeThanksPaul

author: coromonadalix
author_rank: Super Contributor
timestamp: February 25, 2019, 02:28:21 am
content: thakte the 7126 schematics / application note and try to see on your pcb if it match ?

author: PKTKS
author_rank: Super Contributor
timestamp: February 25, 2019, 02:59:54 pm
content: Thanx for you reply.I have even better alternative.The CIC came from an ancient dead DMMI have another old crappy based on the 7126 which probably needsto be replaced. I can try... but murphy said that checking it first is good ...The datasheet would clarify some doubts... as I have already heardthat CIC cloned the 7126 without permission... some time later it vanished.so far no datasheet published... or yet or never available.I will sleep on that testing bench gig..I have just ONE salvaged chipone shotPaul
Marshall JCM800 Lead Series Repair - Power supply Issues - Page 1
Forum section: electronics / repair

author: jcrubin
author_rank: Frequent Contributor
timestamp: February 18, 2019, 01:01:07 pm
content: This JCM 800 landed on my bench had cutout issues as reported and was apparently blowing out fuses. This sounded strange, but since it was blowing out fuses, this is going to have to be put into service position and troubleshoot with the power-off. This will start with a visual inspection. The visual inspection immediately reveals the first issue, which was expanding electrolytic capacitors. Also oxidation is exhibited in the tube sockets. The underside reveals capacitor leakage. During a fuse inspection it was found that the owner was attempting to put higher than rated fuses in the HT side in an attempt to keep the amp running. Hopefully this did not cause any internal damage. The tube sockets were all hit with deoxit after being individually inspected and each tube tested, one finals tube was found to be shorted, very interesting. A strategy is assembled to deflect the circuit board out of the way. This is required to reach one capacitor. With that, all of the caps are swapped out one by one.Part 1 of 2

author: jcrubin
author_rank: Frequent Contributor
timestamp: February 25, 2019, 01:18:59 pm
content: In part 2 we continue testing the caps that were pulled from the amplifier and come to find that while the capacitance was good (with the exception of one that exploded) what it does in term of leak-down and its quickly shown that these had an event that appears to be a condition caused by the amp being turned on after a long time being dormant.Continuing on fuses are re-added and the test speaker is employed, Variac is setup for a test run. With a good smoke test and voltage test, the bias of -37.4 is enough to get going. This gives 32.5ma to get started with 418V on the plate. With noise coming out of the speaker, cracking and cutout, I could quickly identify an issue in the pre-amp stage which turned out to be a failed tube. After this the hum pot is setup for minimum.Testing all of the control with the guitar shows everything to be in working order. Brings us to a first biasing event. I got actual matched sets which tube depot did a meh.... job on so i ended up having to mix and match all of the tubes to come up with something. With the bias completed everything is re-assembled. Everything completed.Part 2 of 2
Problem with TV Toshiba 50L7335DG - Page 1
Forum section: electronics / repair

author: preebi4
author_rank: Newbie
timestamp: February 25, 2019, 12:09:04 pm
content: Hello, I'am having trouble with TV Toshiba 50L7335DG. The tv turns on, backlights is starting but no picture. I think there is audio but not sure because cant test it. There is only noise like working but no input signal. The question is how to understand where is the problem - main board, t-con board or lcd panel. The power supply board seems to be working fine because all voltages are correct. Main board is 32L4300 rev 1.02a, t-con is v420hk1-cs5. I try to find schematics to check some control points but nothing came up ( maybe search wrong i dont know).Thank You!
Looking for a rare thermistency - Page 1
Forum section: electronics / repair

author: engavi
author_rank: Newbie
timestamp: February 25, 2019, 10:13:35 am
content: Hi guys,I have a electronic board from an ECU that has an NTC resistance that opens due to excess heat.In the picture can see two NTC equals, one repaired and other original.It is a typical fault in these plates due to bad design I have seen several plates, all with that problem.I have soldered it terminals several times with solder but it desoldered a few months, due to the great temperature in the componet.This resistance has 170 ohms at room temperature of 20 degrees centrigrados and low to 162 ohms when heated to 35 degrees.All NTCs that I had seen, have a bigger coefficient of temperature.I tried to look for that NTC but I do not find this value or that small curve of variation.Anybody know where get this thermistor or similar?I appreciate any help you give me.Thanks in advance.Regards
Fluke 89 IV not initializing - Page 1
Forum section: electronics / repair

author: psykok
author_rank: Frequent Contributor
timestamp: February 22, 2019, 07:49:37 pm
content: Hi,I have a strange error with a 89IV I bought.The MM is turning on correctly but is kind of not completely finishing the initializing ... It's not displaying 0 in any mode.I have also check current drop and it's okAfter a detailed visual inspection on both side I haven't seen any damages.Any idea what to check next?Alex

author: dacman
author_rank: Frequent Contributor
timestamp: February 22, 2019, 10:38:04 pm
content: First thing I would try is to clean the switch. (I'd use DeoxIT and a lubricant.)

author: psykok
author_rank: Frequent Contributor
timestamp: February 22, 2019, 10:46:49 pm
content: Quote from: dacman on February 22, 2019, 10:38:04 pmYes that is a good thing to do and I have already cleaned the PCB and all contacts.The rotary switch is working and also all function button.Was able to play with setup menu but measuring is still not working.

author: TopLoser
author_rank: Unknown
timestamp: February 22, 2019, 10:52:07 pm
content: I’d be returning it to Fluke under their ‘lifetime warranty’ if I were you.Never been asked for proof of purchase, sometimes they simply return you a new/boxed unit.Fluke are good, like Keysight.

author: psykok
author_rank: Frequent Contributor
timestamp: February 22, 2019, 11:15:50 pm
content: Quote from: TopLoser on February 22, 2019, 10:52:07 pmThe have lifetime warranty for such product? Worldwide?Alex

author: Samogon
author_rank: Frequent Contributor
timestamp: February 23, 2019, 04:03:26 am
content: First: you are measuring AC current.Second : could be switch i have seen same problem one of the contact springs was missingThird: could be bad ASIC, I have seen it too

author: psykok
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:05:24 am
content: The MM was in a position when I took the picture but it's the same for all positions AC, DC , ohm ...I checked the rotary switch there is no missing contacts. I tested also the rotary switch from my 187 and same result.I think the Asic is bad, I cannot imagine these issues coming from side components.

author: psykok
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:28:26 am
content: I had an additional attempt this morning by reflowing the Asic without result

author: Muttley Snickers
author_rank: Unknown
timestamp: February 23, 2019, 09:43:39 am
content: As Samogon already mentioned, the second image shows that your 87IV was set to measure AC current when it should have been set to measure the DC current draw of the 89IV, the selector switch was in the wrong location at the time the image was taken.

author: retiredcaps
author_rank: Super Contributor
timestamp: February 24, 2019, 05:37:15 am
content: Fluke's "lifetime" warranty is clearly documented in their manual. It's not lifetime as many would think in everyday definition of the word.However, as TopLoser suggested, some here have been lucky and gotten their meter repaired or replaced for free without having to meet the terms and conditions of the warranty.
Need help for wiring micro-usb 5pins for bluetooth speaker - Page 1
Forum section: electronics / repair

author: Oriel
author_rank: Newbie
timestamp: February 23, 2019, 09:02:29 pm
content: Hi,I have bluetooth speaker. The charging port has broken.When I opened it and in attempt to extract the old port, I lifted some pads by mistake.I attached some photos of the board.I need help to know how to fix this speaker. Also, I have looked for this part on the internet but I can't find it.This speaker model is "B29 Bluetooth speaker". I can't find any brand on it.Thank you very much.

author: SMdude
author_rank: Frequent Contributor
timestamp: February 23, 2019, 09:16:12 pm
content: It looks to me like only the outside pins are used on that connector. The pads that lifted off were not connected to anything in circuit.Just re-solder the original connector you have.

author: Oriel
author_rank: Newbie
timestamp: February 23, 2019, 09:23:04 pm
content: Just to be sure. Can you see it through the picture (That the 3 middle pins are connected to nothing). So what is their purpose?Another question: The power and ground connectors is the outside pins and that it all necessary?

author: Bratster
author_rank: Frequent Contributor
timestamp: February 23, 2019, 11:08:36 pm
content: The three middle pins are used for data lines. Your Bluetooth speaker only needs ground and 5 volts.you can see one of the outer pins is connected to the copper pour which also connects to The shield pads on the USB connector. That's your ground. The other pin would be your 5 volts.Sent from my Fi Moto x4 using Tapatalk

author: Oriel
author_rank: Newbie
timestamp: February 24, 2019, 12:00:23 am
content: Ok. connect it with those two pins and that all?

author: SMdude
author_rank: Frequent Contributor
timestamp: February 24, 2019, 01:28:11 am
content: Yes, that's it. It just needs power and ground to charge the battery.
Voltraft VC870  - Page 1
Forum section: electronics / repair

author: Sebo
author_rank: Newbie
timestamp: February 19, 2019, 09:20:04 am
content: Hello !I have problem with this voltmeter VC870All ranges auto/manual are ok, except when is on resistance (ohm) setting. Insted showing 0L, it shows 213,99 ohm. I tested every component and found nothing wrong. Sometimes, if you repeatedly short test leads a few times, it goes to autorange. Measure resitance ok except on lower ohm, then it shows again 213 ohm and stay there. If you short circuit test leads it shows 0 ohm, sometimes around 10-15. Manual range at kohm and higher is ok.I have two of these VC870. I got them very cheap, i repaired one, this second gives me headaches ... When you press second function on ohm setting ( beeper ) it is also ok.Both of multimeters on diode test position - test leads shorted, show 0.2470 V, which is also not normal. Must be zero. When measuring diode both show value higher, exactly +0.2470, compared to UT61E ...ES51966A adcAD737 rms-dcMSP430 Mikrocontroller for display/dataAny help would be appreciated.Sorry for my bad english.

author: PKTKS
author_rank: Super Contributor
timestamp: February 19, 2019, 10:32:26 am
content: Very frequently this little cheapos require care on the rotary switchor whatever they use as such to change functions...Cheapos and even some more expensive ones.Those switches are a source of bizarre problemsPaul

author: Sebo
author_rank: Newbie
timestamp: February 19, 2019, 11:03:11 am
content: Thanks for reply !The first one had problem with contacts on rotarity switch, i fixed that. The second one have more serious problem, i can not determine what...

author: Sebo
author_rank: Newbie
timestamp: February 22, 2019, 05:01:40 am
content: Hi !UpdateI have swapped eeprom from the second dmm. Now shows on the ohm range correct value 0L, before showed 213.99 ohm. Does anybody know fastest and easiest way to copy data from good eeprom to currupted one, or get new eeprom dump, or at least how to calibrate these dmms because both have problem on diode function test, when short circuit tleads, they dont show 0 or near it, they show 0,24 V ...

author: Sebo
author_rank: Newbie
timestamp: February 24, 2019, 01:07:47 am
content: I removed eeprom from one dmm, works fine without it, i guess it i for store data and/or calibration.But the problem on diode test remain, on both dmms. It still shows 0,24 V, when short circuited.Voltage on test leads ( both dmms ) in this position is a little more than 4 V. Is this normal ?On UT61E voltage is a little less than 3 V...
Where can I get Triplett VOM model 1200-F data? - Page 1
Forum section: electronics / repair

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: February 23, 2019, 07:45:00 pm
content: I've finally taken a meter I've had for several years off the shelf to see if I could fix and calibrate it. I would like it to be just as good as new again.It's a Triplett VOM model 1200-F in pretty good shape except for a lack of a battery box, a busted pin jack and a sticky push-button switch. I have Googled several times but can find nothing on this instrument. Does anybody know where I can get a schematic or specs on it?Thanks in advance, Tim.

author: barry14
author_rank: Regular Contributor
timestamp: February 23, 2019, 09:18:02 pm
content: Some information can be found at the following site:https://www.radiomuseum.org/r/triplett_volt_ohm_milliammeter_1200f.html
1l=1j gpu memory controller - Page 1
Forum section: electronics / repair

author: hercegovac
author_rank: Contributor
timestamp: February 23, 2019, 08:33:24 pm
content: Looking for help to identify memory controller on the gtx980 labeled 1l=1j?

author: fzabkar
author_rank: Super Contributor
timestamp: February 23, 2019, 08:49:21 pm
content: http://www.smdmark.com/en-US/search/code?id=1l%3DRT8811BGQW, Richtek, Dual-Phase COT Buck PWM Controller with Dynamic Voltage Control, marking 1L=xx, WQFN-4x4-24L:https://www.richtek.com/assets/product_file/RT8811B/DS8811B-00.pdf
HP Spectrum Analyzer 851D Display 8551D RF Unit - Page 1
Forum section: electronics / repair

author: Radio Tech
author_rank: Frequent Contributor
timestamp: February 15, 2019, 05:35:25 pm
content: A while back a viewer drove up and delivered this old HP spectrum analyzer to me. This weighs a ton so shipping would have been crazy.Good thing it was donated so I have nothing in it.I do not do many repair threads. usually just videos. But I want to document the repair in a thread along with videos on YouTube. I have one video on this already.It is #199https://www.youtube.com/theradioshopI have not set a time to start this repair as it will most likely be lengthy. So this is going to take a long time between other normal repairs in the shop.I do think the first order of business on this unit is get it cleaned up. Thing is very dirty as it appears to have set in a garage on a concrete floor for some time.Although in the video I did manage to get the display unit to come on and show a trace. All I did was replace two bad capacitors that was easy to spot. After that the display had a nice crisp trace.So I will start with tearing the RF deck apart, clean, and then start by pulling each board and replacing out of spec components. There is a lot of discolored resistors and most likely more bad capacitors. I also going to have to do a lot of studying on this circuit so I can find my way around it. One thing I noticed is the online manuals are a bit different than the way the unit is built. Specially the RF deck. The manual shows the HV timing circuit on a plug in PCB. This unit does not have that board and the relays and components are chassis mounted. Perhaps I need to find an original manual.Serial numbers:Display unit - 813-02273RF unit - 823-02266Below is some low res pictures of the unit.

author: AF6LJ
author_rank: Unknown
timestamp: February 15, 2019, 09:19:38 pm
content: Power supply issues are not uncommon with these units considering their age.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: February 15, 2019, 11:38:15 pm
content: Quote from: AF6LJ on February 15, 2019, 09:19:38 pmThanks for that tip Sue. Going to need a lot of tips on this one. I printed the manuals for both units. That should give me some good reading material to get to know them. The RF deck manual was 2.5 inches thick.

author: AF6LJ
author_rank: Unknown
timestamp: February 21, 2019, 11:08:51 pm
content: Quote from: Radio Tech on February 15, 2019, 11:38:15 pmI use to have to printed manuals origanials and they went with my 851/8551 when I finally got rid of it./Sue heads off looking for a decent online copy to play along with.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: February 23, 2019, 03:28:34 pm
content: Trying to find someone that has an original manual to see if it is like the unit I have. So far no luck.Really want the manual identical to mine. Will make troubleshooting a easier to follow along with.I got the unit moved over to the other bench now so I can start taking it apart to clean and rebuild boards.All I need is more time....
How to repair metex M 3850 m - Page 1
Forum section: electronics / repair

author: fles
author_rank: Newbie
timestamp: February 16, 2019, 07:05:03 pm
content: Hello Everyone.Today I connected a charged capacitor to the instrument, after which I only have a message on the display.Does anyone know how to get rid of the malfunction.Thank you.

author: Emo
author_rank: Regular Contributor
timestamp: February 16, 2019, 07:45:16 pm
content: Hi,Probably the maxim MAX130CPL or the equivalent intersill 7106A has been overloaded due to the capacitor still having too much charge. This chip is mounted just underneath the LCD display.Eric

author: fles
author_rank: Newbie
timestamp: February 17, 2019, 06:06:21 pm
content: There is a different situation on this type than with me.Is it possible that the marked elements in the images are damaged because they were first affected by a charged condenser?

author: fles
author_rank: Newbie
timestamp: February 22, 2019, 06:14:41 pm
content: Is there any idea?

author: Emo
author_rank: Regular Contributor
timestamp: February 22, 2019, 06:55:22 pm
content: Hi,Your version also has a service manual availablehttps://elektrotanya.com/metex_m3830_m3850.pdf/download.htmlAre all ranges faulty, or just the capacitance range?

author: coromonadalix
author_rank: Super Contributor
timestamp: February 23, 2019, 04:47:19 am
content: same as Emo saidStart with each range / function check the 2 fuses toochances ic4 may have busted and or the ic 5 too
When lever microswitches go bad.  - Page 1
Forum section: electronics / repair

author: wilfred
author_rank: Super Contributor
timestamp: March 02, 2019, 02:52:57 am
content: I am dealing with a set of new(ish) gate operators (Elite SGO-1) that are intermittently operating erratically. The two symptoms are the gates overlap, ie close in the wrong order, or only one of the pair moves.Now I have been told that this can be explained by faulty limit switches giving the controller a false idea of the position of the gate and that seems plausible. However my specific question is what is the failure modes of such microswitches and new ones in particular? And intermittent faults at that. The gates could work 60 or 70 times before showing a fault.New ones will be installed on Tuesday and I'll know one way or the other soon after. But I'm happy to take opinions. Remember these are new motors and hence new microswitches. The old units lasted reliably for 11 years and the motor brushes were the reason for replacing them.What are the chances a microswitch expert will read this and give me a link to some industry report on microswitch failures? I'd read it.

author: floobydust
author_rank: Super Contributor
timestamp: March 02, 2019, 04:01:03 am
content: The Elite SGO-1 manufacturer's service manual specifies"Zippy"brand microswitches VMH 15H 04 C they sound so reliable.Check the current rating on the replacement microswitches, as they widely vary.If the limit switches are in series with the motor, that might be why they don't last- carrying the motor's high current. Some machines do this with limit switches so that even a MCU failure will not cause troubles, the limit switches alone are a safety function.Zippy VMH I cannot find datasheets for. The VM is rated 5A, so the VMH might be a special version.Microswitch (Honeywell) V15 series have higher current 16A, 22A, 26A ratings or gold contacts for MCU logic inputs, if contact oxidation there is your problem.What goes bad - is it the contacts, the mechanical toggle etc. ?

author: wilfred
author_rank: Super Contributor
timestamp: March 02, 2019, 05:41:41 am
content: I'm pretty sure the microswitches are just to monitor the gate open and close positions. The controller has relays to drive the motors. there are three wires for the two switches and two wires for the motor.Thanks

author: Muttley Snickers
author_rank: Unknown
timestamp: March 02, 2019, 06:36:44 am
content: Quote from: wilfred on March 02, 2019, 05:41:41 amMany early gate openers incorporated adjustable cams which dictate the timing and limit sequence in regards to the microswitches, these switches were wired directly to the controller board as you mentioned. I would suspect a sticky switch which has been subject to contamination such as dust or lubricants, either that or they have been poorly aligned, mounted or tensioned.
Weller WCB2 temperature display adjustment - Page 1
Forum section: electronics / repair

author: carl_lab
author_rank: Frequent Contributor
timestamp: February 22, 2019, 10:30:29 am
content: Can somebody help me to adjust temperature display of a Weller WCB2?I turned the two pots inside, but display did not change.http://www.testequipmentdepot.com/weller/pdf/wcb2_data.pdf