hybridfree/eevblog-posts huggingface dataset:
TDA7492 Power - Page 1
Forum section: electronics / beginners

author: modernjack3
author_rank: Contributor
timestamp: July 06, 2016, 05:39:07 pm
content: So ist me , the car battery guy again and I am having a big Problem - I just figured out tht my battery guard isnt really made for Music use since this Is a Wave and no constant current - and I just wondered if I could do it by time instead - Can I use the datasheet of the TDA7492 and the 8 Ohm load curve ?I want to get my supply voltage for this board :https://www.amazon.com/KKmoon-Wireless-Bluetooth-2-channel-Amplifier/dp/B01BV8LM5Qdown to 13 V so it can Output a MAX of ~15 W per channel ( says the datasheet) is my thought correct ? Does the datasheet even fit to my board or is there a step up conv built in ?so many questions ...Datasheet :http://www.st.com/content/ccc/resource/technical/document/datasheet/f4/3e/da/a3/97/e7/4f/8d/CD00205863.pdf/files/CD00205863.pdf/jcr:content/translations/en.CD00205863.pdf8 Ohm caracteristics..Greetings Jack !PS : My battery says "650W if discharged over 20 Hrs" so id like it to drain about 32W
Adjusting TDK power supply above rated voltage - Page 1
Forum section: electronics / beginners

author: GG
author_rank: Contributor
timestamp: February 17, 2025, 09:28:18 pm
content: Dear EEVblog,The specs for the RGC4W300W008A DC-DC converter say the max output voltage it can be trimmed to is 48v but I'm wondering if I could safely trim it to 54v?I wouldn't be operating it anywhere near max load, it can sustain 300w but I would be using it around 80w tops.I've attached the manufacturer trim specs.Looking forward to what y'all think about this.

author: benj38
author_rank: Frequent Contributor
timestamp: February 17, 2025, 09:55:51 pm
content: The datasheet is very clear about 48V being the maximum. It is not just a question of power draw, but of maximum voltage rating of parts (e.g., capacitors) inside, and other factors.Without looking inside and analyzing the circuit and components used, my answer would be : "No, you can not operate this unit at 54V output, regardless of the current draw".

author: GG
author_rank: Contributor
timestamp: February 17, 2025, 10:03:53 pm
content: Looking at something like this from RECOM, the manufacturer actually says +15% trim over the top is allowed on page 1:https://recom-power.com/en/products/dc-dc-converters/dc-dc-converters-regulated/rec-p-REC300H-2448SW.html?6I'm checking if TDK says anything like this as well.

author: edavid
author_rank: Super Contributor
timestamp: February 17, 2025, 10:05:18 pm
content: Look at the equation - with a 0 ohm resistor you would only get 49V out.To go higher you would have to find the 750 ohm series resistor inside the power supply and reduce that.I agree, there's no way of knowing if that would work fine, blow up the supply, etc.P.S. Please try to make your thread titles more clear, like "adjusting TDK power supply above rated voltage".

author: GG
author_rank: Contributor
timestamp: February 17, 2025, 10:08:47 pm
content: Thank you I didn't think about checking what 0 ohm would result. Good stuff!For me "out of spec" is perfectly clear, but I adjusted the title just for you
Teac A-1200 Reel to Reel  - Page 1
Forum section: electronics / beginners

author: Johnny Pruett
author_rank: Newbie
timestamp: February 15, 2023, 11:24:07 pm
content: I have a Teac A-1200 Reel to Reel Im getting noise from the right side speakers like a off radio station noise The VU meter on the Right side is bouncing up and down like there music playing but its none playing And the Capstan motor runs constant is the Capstan motor for the pinch roller suppose to run all the time and like i mention the VU meter is steady bouncing with no music playing WHY i need help Thanks

author: james_s
author_rank: Super Contributor
timestamp: February 15, 2023, 11:30:11 pm
content: The service manual can be found here, that should get you started.https://www.synthxl.com/wp-content/uploads/2020/11/Teac-A-1200-Tape-Deck-Service-Manual.pdf
Teardown BWüE Platenspeicher MPS 90-160E and help identifying type of board. - Page 1
Forum section: electronics / beginners

author: jorgeh
author_rank: Regular Contributor
timestamp: July 30, 2022, 05:58:57 pm
content: HiI received last week more stuff from the army surplus. and im having trouble identifying the purpose of a board.the computer is a ATM Typ MR 8020.for example here is a component BWÜ Platenspeicher it would be army surveillance or biological weapons convention.Platenspeicher would be memory disk. although for the look of the board it looks more like a controller.Hope you like the teardown.the board in question it looks like a memory board im posting it under

author: jorgeh
author_rank: Regular Contributor
timestamp: July 30, 2022, 06:04:03 pm
content: This is the board
Teardown of a simple LED toy - Page 1
Forum section: electronics / beginners

author: echo34
author_rank: Newbie
timestamp: February 14, 2019, 12:49:35 am
content: I'm trying to understand the electronics inside this LED toy (please see attached photos of the device in operation, as well as torn down). The operation is very simple. A push button switches between 7 different modes of operation of an RGB LED, including solid white, flashing red, flashing blue, flashing green, flashing R-G-B in sequence, gradual rainbow color change, and off. It operates on 3 - 1.5V cell batteries in series (1 AG13 + 2 AG10's for a total of 4.5V). The only components on the PCB are a bare IC die, an RGB LED, and a pushbutton switch. There are no discrete resistors or caps.I'm trying to figure out what chip and manufacturing process was used, and how I might be able to do a similar project. It looks like the 1mm by 1mm bare die was directly attached to the PCB. I assume there were tiny bond wires connecting the pads on the die to traces on the single-layer PCB board that lead to the other components (RGB LED, battery terminals, and pushbutton switch), however I wasn't able to locate the tiny wires after I broke down the product. And then it looks the IC die and bond wires were altogether encapsulated in a blob of white resin/epoxy.Has anyone seen this type of manufacturing before? Do you think the bare die is a microcontroller or custom ASIC? I'm hoping it's an OTP microcontroller that can be pre-programmed with my own design at the time of procurement. Do you know a specific manufacturer who can make this? Fwiw, the toy indicates that it's made in China.Btw, first time poster here. I'd appreciate any advice. Thanks!

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2019, 12:58:07 am
content: That's chip-on-board, which is commonly used in very low-cost electronics, like toys and calculators.Take a look athttps://learn.sparkfun.com/tutorials/how-chip-on-boards-are-made/allAs for those specific chips, who knows. It's probably a custom chip (they make LEDs with a similar driver built right in!), but it could be a microcontroller.

author: mayor
author_rank: Regular Contributor
timestamp: February 16, 2019, 12:11:21 pm
content: Dunno anything about manufacturing processes for custom COBs, but check out this thread :https://www.eevblog.com/forum/microcontrollers/3-cent-mcu/Dave did a video of it. Seems this could be a good alternative driving an RGB LED through PWM or APA102C or whatever...
TecArc 206i Tig Welder - Cleaning & Setting The HF Electrodes - Page 1
Forum section: electronics / beginners

author: RichKem
author_rank: Contributor
timestamp: June 08, 2022, 05:07:12 pm
content: I have posted some photos below of a small procedure which should be of interest to some members who own a TecArc Welder.1. Remove the electrodes2. Clean the electrodes with a small file or wet & dry paper3. Re-install the electrodes4. Set the spark gap to 0.9mmSee photos below................................This is NOT engineering or welding advice so do not UNDER ANY CIRCUMSTANCES follow what I do
Technique for discharging an old Tektronix 5440 CRT - Page 1
Forum section: electronics / beginners

author: rpbale
author_rank: Newbie
timestamp: September 30, 2016, 03:25:57 pm
content: Hi, I have an old Tektronix 5440 scope and would like to know what technique the pros use for discharging the CRT on this scope. The CRT is hidden behind a shroud so getting to the HV line right on the CRT is difficult. There is access under the HV component area. I know that the fact that I'm asking such a basic question is a red flag in itself. But I do want to know how others tackle this on this unit. Thanks, Rick

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: September 30, 2016, 04:32:10 pm
content: 1) Join tektronix yahoo group,https://beta.groups.yahoo.com/neo/groups/TekScopes/info2) ask question there (or just search, lots of past info). There be videos.3) take my non-working 5440 off my hands.Insert emojis here

author: rpbale
author_rank: Newbie
timestamp: September 30, 2016, 05:10:47 pm
content: That's funny. I should as I might need your parts!Thanks

author: tautech
author_rank: Super Contributor
timestamp: September 30, 2016, 06:17:38 pm
content: As with all CRO's that have PDA, a well grounded screwdriver connected to the chassis, unpowered of course.More than once too.

author: David Hess
author_rank: Super Contributor
timestamp: October 02, 2016, 06:17:36 pm
content: I am not familiar with the internal arrangements of the 5440 but on other Tektronix oscilloscopes, there is a high voltage connector in-line with the high voltage PDA lead. This connector can be pulled straight apart leaving the pin going to the CRT exposed and this pin can then be shorted to the chassis to discharge the CRT. The side going to the high voltage multiplier is shielded deep inside the high voltage connector so it is safe to operate the oscilloscope when the connector is separated.If the oscilloscope is powered down for minutes to 10s of minutes, then the PDA voltage will discharge through the resistive coating to ground inside the CRT.
Techniques to reduce the input capacitance of an amplifier stage - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: September 15, 2019, 06:31:18 am
content: Forto reduce input capacitance, could anyone advise how to derive the equivalent Cbe or Cin for the first and last methods ?Note: I have drawn out the small-signal model for the first method, but it is not helping.
Techtronix 5110 - Page 1
Forum section: electronics / beginners

author: TerryCtjc
author_rank: Newbie
timestamp: May 17, 2020, 03:24:21 pm
content: I have a Techtronix Oscilloscope Model 5110 The display is restricted to the top right hand quarter of the screen and cannot be moved by the position controls to any other area of screen. When try to move display to bottom of screen trace stays at center and magnitude of waveform decreases. Any help or advice as where to look for problem would be most helpful.

author: perdrix
author_rank: Frequent Contributor
timestamp: May 17, 2020, 03:39:35 pm
content: You'll never pass a spelling test! Tektronix, not Techtronix!Anyway, the first thing to do is to get a copy of the service manual (try Artekmedia if you can't find a free copy) and to read it you may find that will give you the answer!It never hurts when dealing with these old 'scopes, to check that all the power supplies are correct (voltage and ripple).Other than that, you're likely to get the most help from either the Tekscopes or Tekscopes2 (a schism from Tekscopes) mailing list, both at groups.io.David

author: TerryCtjc
author_rank: Newbie
timestamp: May 17, 2020, 04:37:38 pm
content: Thank you for your suggestions.
Teflon (PTFE) Tefzel (ETFE) stripping? - Page 1
Forum section: electronics / beginners

author: wilfred
author_rank: Super Contributor
timestamp: November 06, 2013, 04:24:45 am
content: /.

author: Kjelt
author_rank: Super Contributor
timestamp: November 06, 2013, 08:43:00 am
content: if it is manual stripping and you are sure that it is exactly AWG28 this would be a good wire stripper but even these will from time to time nick the inner wire:http://uk.farnell.com/ck-tools/t3756-30/wire-stripper-0-30mm/dp/146420Also read this electrical wire stripper topic, however not within your price it still has some valuable manual stripper tool info in it:https://www.eevblog.com/forum/beginners/thermal-wire-strippers-are-they-good/msg320220/#msg320220

author: amyk
author_rank: Super Contributor
timestamp: November 06, 2013, 10:51:42 am
content: Thermal decomposition of fluoropolymers produces some rather nasty chemicals, including hydrofluoric acid.

author: F4CPY
author_rank: Contributor
timestamp: November 06, 2013, 12:39:29 pm
content: I often use #28 to #30 AWG wire (strain gages soldering) and mechanical strippers have never done the best job as a heat stripper (for PTFE insulating), but using an aspiration hood (don't know the right term in english!). I heat the strips below 300°C (melting point about 327°c) and only make a gentle mark on the vire.Some studies (look at wikipedia) said that PTFE starts to decompose near 200°C, so don't breathe the smoke!If someone have a good trick...

author: robrenz
author_rank: Super Contributor
timestamp: November 06, 2013, 12:56:16 pm
content: Theselook like the ducks guts for what you are after. Yeah a little more than what you want to pay but probably your best bet.Edit:Same tool lower price. picture says Clauss on the handle so it should be same stripper
tek 2215 crt shield - Page 1
Forum section: electronics / beginners

author: ME
author_rank: Frequent Contributor
timestamp: February 17, 2025, 11:15:04 am
content: I have a crt from a dead tek 2215 scope, would i be rite in thinking its metal shield id mu metal?,if so can it be used for rf shielding?.

author: jonpaul
author_rank: Super Contributor
timestamp: February 17, 2025, 12:14:23 pm
content: no the Netic/CoNetic high mu metal is only for magnetic fileds at low frewq.Any metal like aluminum can be an effective shield for RFSee Perfection Mica supplier of sields andTektronix circuit concepts books on CRTs.j
Tek 2225 cleaning - Page 1
Forum section: electronics / beginners

author: Http 418
author_rank: Newbie
timestamp: June 02, 2013, 08:31:34 pm
content: Hi allSo trying to setup a small home lab, since Dave inspired me. So surfing abit online turned up a tek 2225 at a desent price. Unfurtunatly it didnt come with any probesSo first newbie question; what probes do I need? I found a set of the probes the would have came with scope, but they aren't exactly cheap, so can I just get a set of 100 Mhz off ebay or is that bad idea?So as Dave allways say's, don't turn it on, take it apartbut the only revealed alot of dust, but not the good kind that you can get rid of with compressed air. Apparently it has been sitting om a smokefilled room and now all the dust is sticking to every thing.What is the best way to clean the interior? Iso alcohol and q-tips or is the another way? What is the best alcohol to use? Iso or denatured?Last question ( atleast in this post ) the channel 1 volts/div switch is really hard to turn and it isn't clicking into position as easily as channel 2, the problem seems to be linked. I'm hoping that the switch just needs a good cleaning. Would Kontakt chemie no. 61 do the job or would it be better to get a pure contact cleaner without any corrosion protection?

author: G7PSK
author_rank: Super Contributor
timestamp: June 03, 2013, 04:23:06 pm
content: I have just had a similar problem, the scope was full of toner from a photo copier or lase printer, I put the boards into a large container with a gallon of denatured alcohol (meths) and swirled it around then blew of the excess and allowed to dry.

author: c4757p
author_rank: Super Contributor
timestamp: June 03, 2013, 04:27:27 pm
content: Yes, most everything in there is safe to immerse in alcohol. I recently replaced a load of crusty capacitors in my 2445A, so the boards were thoroughly coated with flux, and I just took off the ceramic hybrids and the attenuator assemblies and dunked even the whole main board in denatured alcohol.

author: KJDS
author_rank: Super Contributor
timestamp: June 04, 2013, 04:16:04 pm
content: Quote from: c4757p on June 03, 2013, 04:27:27 pmHIC! just tried it and it's mostly good, buer my vsipons is wonly sldkfzsc dfxg sef

author: selkathguy
author_rank: Unknown
timestamp: June 04, 2013, 04:17:49 pm
content: Quote from: KJDS on June 04, 2013, 04:16:04 pm+1 good post

author: millerb
author_rank: Regular Contributor
timestamp: June 04, 2013, 04:42:19 pm
content: I wouldn't bother trying to clean it up unless it wasn't working properly. A dirty oscilloscope is more useful than a ruined clean oscilloscope.As for probes, the cheapies on eBay and Amazon are usually fine. A few months ago I picked up 2 100MHz probes for $20 on Amazon. They're labeled "Yang Xun". You get what you pay for. One probe was a little flaky to adjust and the 1x/10x switch was a little wonky.Then again, the guy who sold it, shipped it in a plastic bag so that may be the fault of being banged around in the mail.

author: houdini
author_rank: Regular Contributor
timestamp: June 05, 2013, 04:39:18 pm
content: yea i just got the cheap ones off eBay for my 2225 and they work fine.
TEK 2232 analog scope questions - Page 1
Forum section: electronics / beginners

author: cobbler
author_rank: Unknown
timestamp: December 11, 2015, 08:44:16 pm
content: Hello players, I have a very simple circuit where a line goes high to 5V for three seconds and then low to 0V for three seconds.I am trying to learn to use my TEK 2232 scope which has the Measurements feature while in STORE mode (digital storage). Having a problem getting the voltage measurement to read accurate on the scope.I attached the two methods the Operators Manual describes to read voltage.... in "normal mode" (the distance between Cursor1 and Cursor2), and "Referenced to Ground".I followed both procedures in the manual and no matter what settings I use,the cursors never display any voltage greater than 0.6V !In the attached screenshot you will seethe Fluke DMM is displaying correctly 5.0V but the Tek is displaying only 0.6VCan any old players help a young player out of this trap?

author: gmarentette
author_rank: Newbie
timestamp: December 11, 2015, 09:50:58 pm
content: It says to put one cursor on a low point and the other on a high point. Are you doing that?

author: cobbler
author_rank: Unknown
timestamp: December 11, 2015, 10:26:12 pm
content: Quote from: gmarentette onTodayat 03:50:58 AMYes you can see here in this pic I am using the "between cursors" delta method, it still reads incorrectly0.500V

author: w2aew
author_rank: Super Contributor
timestamp: December 11, 2015, 10:29:58 pm
content: You are using a 10x probe that does NOT have the sensing pin that tells the scope that it is a 10x probe. So, the scope doesn't know that the voltage scale needs to be multiplied by 10x, hence your voltage is off by a factor of 10.http://www.jmargolin.com/projects/TekReadout_files/image003.jpgYou can also tell that this is the case because you've got a 5V step, but the scope is showing 1 division of deflection and it shows that it is on a 0.5V/div scale.

author: cobbler
author_rank: Unknown
timestamp: December 11, 2015, 11:10:58 pm
content: Ok thanks w2aew, now changed it to 1X on my generic probe and it is reading correctly. BTW thanks for your great videos, today I finally figured out how to view "two waveforms" using the A/B delayed sweep from watching your video on that... the buttons/dials were completely different than your scope but finally figured it out! That has been puzzling me for weeks.Off to ebay to find some used tek probes!
Tek 2246A Sweep Problem: Bad Caps, Odd Voltages - Page 1
Forum section: electronics / beginners

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: April 02, 2015, 03:29:20 am
content: My Tektronix 2246A suddenly developed a sweep problem over the weekend. On some ranges, the sweep just stops and on others, it works OK, but sometimes can't make up its mind.First thing I did was check voltages and have some concerns there. But before we go into that, let's talk capacitors. I rigged up my HP 8648B sig gen and Tek 2236 scope to act as an ESR tester. All the caps in the machine look fine except C307B (0.0099 uF 50V) and C307C (0.1 uF 35V). C307A seems OK. Those are 2 of the 3 timing caps in the A Sweep circuit.Well, I can't find any direct replacements anywhere and started thinking about substitutes, but wanted some input before I make a less-than-ideal decision: These 3 caps appear to have been sold in the past as a set and are large axial devices. I'm wondering how well-matched they need to be and what types would make good replacements. I *think* they're non-polarized, so I'm thinking that film caps may be appropriate. Also, the 0.0099 uF seems quite specific -- would it be correct to replace it with an 0.018 uF and 0.022 uF in series?Next, the power supply voltages look a little wonky:PinSpecMeasured1130VAC116.2VAC2GndGnd3+130 V+135.1 V4+55+59.85-7.5-7.66+7.5+7.47+15+14.98-15-16.09-5-5.310GndGnd11Line TrigYes indeed12+5+5.213+5+5.2I'm wondering if those numbers are alarming enough to stop what I'm doing and consider this a bigger project than I first thought. Thanks in advance for your consideration.
Tek 2465A - Page 1
Forum section: electronics / beginners

author: gnif
author_rank: Unknown
timestamp: February 24, 2013, 06:02:35 am
content: Hi All,I bought a Tek 2465A a few years back which I like as it is a pretty nice CRO, I chose to buy it over a cheap DSO as at the time I did not know enough to be able to pick a DSO and had not discovered the EEVBlog.I bought this CRO for next to nothing because it was showing a fault code, which the service manual stated was a low battery. When the unit was delivered, it was working fine, I have never seen the fault code. My question is, was there calibration data in the scope that may have been lost? And if so, how would one go about having it corrected/calibrated, and what kind of cost would be involved?

author: c4757p
author_rank: Super Contributor
timestamp: February 24, 2013, 06:07:58 am
content: It runs a checksum validation of the calibration RAM when it starts - if it doesn't complain it's fine. You should replace the battery, though.

author: gnif
author_rank: Unknown
timestamp: February 24, 2013, 06:30:28 am
content: Thanks for the quick reply. I will have to check out what kind of battery it requires and add it to my list of things to order.

author: c4757p
author_rank: Super Contributor
timestamp: February 24, 2013, 06:34:35 am
content: LTC-7P (still available at Mouser - sit down before you look at the price). I replaced mine with a Tadiran TL-5104/P though - bit of a squeeze to fit it in, but it is cheaper and easily meets the specs of the original.Be careful about how you change it - if you let the RAM power down at any point you will lose your data.

author: gnif
author_rank: Unknown
timestamp: February 24, 2013, 06:41:03 am
content: Wow, it is pretty expensive. The alternative also has a much higher capacity, the meter should be long gone by the time it goes flat.I watched the recent videos of the DIMM tear-downs Dave did which goes into replacing these things thankfully, otherwise I would have just done it without knowing. Would unplugging the CRO be enough to isolate the positive side of the battery from my iron?

author: c4757p
author_rank: Super Contributor
timestamp: February 24, 2013, 06:46:26 am
content: Yes, but you will obviously have to patch in a third power source to hold it over temporarily. I recommend a battery, not a bench supply, and I recommend soldering all the temporary connections, so nothing can shut off or fall off.
Tek 453 Calibrator Fuzziness - Page 1
Forum section: electronics / beginners

author: Cranberry
author_rank: Contributor
timestamp: July 29, 2014, 03:06:17 pm
content: Hi Everyone,This is the first time I've ever used an analog scope or owned a scope before. I'm more or less new to it, but familiar based on my previous classes. I bought this tek 453 off of ebay and received it a week ago. I tested it by measuring some batteries and also the DC output from a wall wart. Measuring DC is fine, I also got the AC signal from the wall wart by not connecting the negative leg to the ground reference of the probe.Anyway, I don't have a function generator so I've been using this to test it. I was trying to follow the manual's instructions for first-time use by hooking up channel 1 or channel 2's BNC connector to the calibrator which should be a 0.1v or 1v peak-to-peak square wave (according to the manual). I don't get that. I notice a difference on the screen, a little bit of noise, but no square wave. It looks more or less grounded. I notice if I put my hand closer to the BNC cable or lift it up I could amplify the signal, but it still looks more or less the same way. I know this isn't right. What could be some of the likely causes of this? Could it just be a broken calibrator? Could this indicate something larger in terms of whether the scope is not in good shape?I tried with another probe (that doesn't hook like the probe I was using before, it's more of a needle), and I couldn't see a thing. With that being said, I don't know if it is a probe issue.I have photos but I have trouble uploading on this site without the entire post getting wiped out.

author: Wh1sper
author_rank: Regular Contributor
timestamp: July 29, 2014, 03:19:55 pm
content: Build a simple two transistor multivibrator using some spare parts flying around and try out.Something like this:http://www.electronics-tutorials.ws/waveforms/astable.htmlAND Read the manual for this scope.An scope is not for measure plain DC. With the built multi vibrator, there you have plenty of signals to try thing out

author: Cranberry
author_rank: Contributor
timestamp: July 29, 2014, 03:28:15 pm
content: I'll try that transistor circuit later tonight and let you know what happens. I have been reading the manual. Here is a picture of the AC signal I got from the wall wart. Ignore the uncalibrated lights, I didn't know what I was doing a few days ago until I read the manual, and asked questions.

author: Wh1sper
author_rank: Regular Contributor
timestamp: July 29, 2014, 03:39:46 pm
content: The signal is normal for just connect the probe with your finger tips.I guess your gear is quite fully functional

author: David Hess
author_rank: Super Contributor
timestamp: July 29, 2014, 04:10:12 pm
content: The AC signal from the wall wart will be distorted without a ground reference because it is isolated. What you will see instead is capacitively coupled noise.It does look like there is a problem with the calibrator output though. A relatively clean square wave should be plainly visible.
Tek 465B needs some minor fixes - Page 1
Forum section: electronics / beginners

author: bitwelder
author_rank: Super Contributor
timestamp: January 03, 2013, 07:01:40 am
content: Some time ago I finally became a happy owner of an old Tek 465B + DM44.I've been following W2AEW's tutorials to fully understand the potentiality of analog scopes. Thanks!The scope is basically ok, but it has a couple of minor issues:- one knob is slightly broken- the probe that comes with it (a P6105) has the pin for the 'Tekprobe' interface that has lot its spring.So my questions are:- where can I buy some replacement knobs at a *reasonable* price?- is there any way to repair the probe pin?- I'd like to get at least a second probe. Which model would you suggest me to get?TIA

author: BravoV
author_rank: Super Contributor
timestamp: January 03, 2013, 07:23:09 am
content: Quote from: bitwelder on January 03, 2013, 07:01:40 amApart from ebay, try here :http://www.sphere.bc.ca/test/index.htmlhttp://www.qservice.tv/vpasp/default.asp

author: aghp
author_rank: Regular Contributor
timestamp: January 03, 2013, 07:49:19 am
content: If you do not need very fast, I have some (also old Tek465) spare part units and some couple of mixed selection of Tek probes, some broken, some perhaps ok.But these old things are deep in my scrap storage ("spare part storage") and it may take time to find what you need becous this is not my primary work.You can PM by finnish.edit: as BravoV tell one source is Qservice, and with my experience it have been also reliable source.

author: w2aew
author_rank: Super Contributor
timestamp: January 03, 2013, 03:24:51 pm
content: Quote from: bitwelder on January 03, 2013, 07:01:40 amYou're welcome. You'll find that many of my videos feature the 465B, including the ones that discuss the triggering controls, AC/DC coupling, AUTO trigger mode, ADD/INVERT controls, Rear Panel I/O, etc.
Tek 465B Volts/div mechanical issue - Page 1
Forum section: electronics / beginners

author: Moose42
author_rank: Newbie
timestamp: December 26, 2024, 04:35:31 pm
content: Hi folks,I’m posting this in the beginner section as I’m an (old) beginner when it comes to scope repair… but I imagine it is a nontrivial problem. The Channel 2 Volts/div on my Tektronix 465B is stuck solid. The var spins freely but the main shaft is stuck. Peering inside, it seems that the grey plastic barrel around the shaft is fractured on the seam. It could be an easy fix if it weren’t for the access. How does one remove and repair the volts/div mechanical internals on a 465B? Thanks in advance!-Moose

author: Old Printer
author_rank: Frequent Contributor
timestamp: December 26, 2024, 04:54:42 pm
content: Do you have the service manual?If not, here is a link to it on the BAMA site:https://bama.edebris.com/download/tek/465b/465b_svc.pdf

author: Moose42
author_rank: Newbie
timestamp: December 27, 2024, 09:56:20 am
content: Hey thanks!

author: awesomechapro
author_rank: Contributor
timestamp: January 05, 2025, 08:37:36 pm
content: Zenwizard Studios on YouTube has a very good video on the disassembly of a 465B that helped me fix my 465B. Might be worth a look, just skip to the part you need. Good Luck!
Tek TDS 420A - 200Mhz Bandwidth having 100 MSamples/s? - Page 1
Forum section: electronics / beginners

author: pnm
author_rank: Newbie
timestamp: October 10, 2022, 12:45:24 pm
content: Hi,I'm just about to get my first oscilloscope kindly providedfor free by a friend of mine. It's an old lady, a Tek 420A,though I think it's absolutely sufficient to get me going.I wonder how this digital scope can be rated with ananalog bandwith of 200Mhz taking only 1 million samplesper second max?According to Nyquist's sampling theorem the frequency f_sampleshould be at least twice as big as f_signal to reproduce thesignal, and be my understanding that simply doesn't work out.Any ideas/thoughts on that?Christoph

author: Warhawk
author_rank: Frequent Contributor
timestamp: October 10, 2022, 12:49:27 pm
content: This is quite common for early digital oscilloscopes. The analog front-end has truly the given bandwidth, e.g 200 MHz. The signal-processing chain (ADC) usesequivalent time sampling. It generally expects that the signal is periodical and with every new trigger it adds a slight delay to the sampling point. It pretty much "scans" the periodical signal several times.This has, unfortunately, many limitations. Especially single-shot events are not friends with this approach.More on this here:https://www.tek.com/en/documents/application-note/real-time-versus-equivalent-time-samplingPS: Welcome to the forum and congratulations on your new scope. You can still have a lot of fun with it.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 10, 2022, 12:52:36 pm
content: Hi pnm, welcome to the forum.There is a thing called equivalent time samplinghttps://www.tek.com/en/documents/application-note/real-time-versus-equivalent-time-samplingand it might be used in the scope you refer to.I'm not familiar with the one you mention so can't say for sure that it is using this.Another point, you mention in your description 1 million samples, but in the thread title you state 100MSamples/s, so which is it.Warhawk beat me to the punch.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: October 10, 2022, 01:47:48 pm
content: Quote from: Warhawk on October 10, 2022, 12:49:27 pmThis is still a thing in new scopes for very high speed, where it can give both cheaper scopes for a given bandwidth and also a significantly lower noise floor.

author: Warhawk
author_rank: Frequent Contributor
timestamp: October 10, 2022, 03:41:36 pm
content: Quote from: TheUnnamedNewbie on October 10, 2022, 01:47:48 pmYes, you're right.

author: pnm
author_rank: Newbie
timestamp: October 10, 2022, 03:53:39 pm
content: Thanks guys, I learned something new today, never heard about ETS before ... makes perfect sense
Tek TDS744A  broken - Page 1
Forum section: electronics / beginners

author: Jeff5
author_rank: Newbie
timestamp: September 11, 2022, 09:09:41 pm
content: Hello everyone. I found a TDS744a for sale that turns on but screen does not work. I know nothing of Tek scopes and their value. Would this be a good find and what kind of support can I get to get the scope up and running again. price is about 200. May be just a screen and if so I might just run a VGA monitor for the scope. I saw on you tube issues with the memory and needing to create backups. Should I stay away from this scope or try my chances? Would some of you be willing to help me fix this scope? I know next to nothing on GPIB, memory of that era and writing scripts.Just a little background on why I'm interested in this scope. I do automotive ECU repair and looking to get a fast scope to play with automotive Ethernet. Plus I want to play with what Dave does in the videos. My budget is very low.Thank you, Jeff

author: CaptDon
author_rank: Super Contributor
timestamp: September 11, 2022, 10:38:16 pm
content: For you personally, probably not worth your time. I say this because the absolute cause of the screen being dark is unknown. Anything from main power supply board being dead to a locked up CPU board. The Dallas chips almost certainly need replaced. For people well versed in the 500/600/700 series it may be an easy fix. For someone with no experience it will probably be one of your worst investments. A working fully functional 744A is probably worth upwards of $500 USD. The external VGA is incredibly nice for classroom demonstrations on big VGA flat panel monitors!

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: September 12, 2022, 06:49:03 pm
content: If it is just the screen there are aftermarket LCD replacements, but the investment for that is more than the price of the scope. Also, I've tried using the VGA output and it is nice for demos, but aligning the soft buttons around the screen with what is on the VGA display is frustrating. Further, a working shutter display is just gorgeous on those scopes. Try to find one with a working display.

author: rooppoorali
author_rank: Regular Contributor
timestamp: September 14, 2022, 03:00:14 pm
content: Here is a tutorial series on repairing Tek TDS744A:

author: james_s
author_rank: Super Contributor
timestamp: September 14, 2022, 05:25:08 pm
content: Whether related to the display issue or not, the scope is probably going to need a pile of SMD electrolytic capacitors replaced. The leaking electrolyte does serious damage to the boards, these are complex instruments that can be difficult to repair. Great scopes when they work though.
Tekpower TP-3005D-3 - Page 1
Forum section: electronics / beginners

author: jobog
author_rank: Regular Contributor
timestamp: March 14, 2016, 02:08:37 am
content: Does anyone have or know where to find a manual for this power supply that isn't written in Chinglish? Really confusing trying to figure out what they are saying when using the supply in series or parallel. Also, is the Instek GPS 2303 similar enough to the Tekpower that I could use that manual? The Instek manual seems to be a little easier to understand.

author: jobog
author_rank: Regular Contributor
timestamp: March 14, 2016, 06:29:55 am
content: Thanks, but that is the manual for the single supply not the double. Doesn't address the series and parallel operation of the double supply.
Tektronics 2221A permanent horizontal line normal? - Page 1
Forum section: electronics / beginners

author: the1one
author_rank: Newbie
timestamp: November 05, 2023, 05:58:32 pm
content: Hi ! Got my first tektronics osciloscope yayi wonder if the small ca. 0.5 cm horizontal line is perfectly normal?the line is permanent in analog and digital store mode, but not in setup menues. Thanks !Please see attached picture.

author: BillyO
author_rank: Super Contributor
timestamp: November 05, 2023, 11:22:57 pm
content: Yes. it's normal and is mentioned in the user manual on page 2-7.https://xdevs.com/doc/Tektronix/TEK%202221A%20User.pdf

author: David Hess
author_rank: Super Contributor
timestamp: November 06, 2023, 09:36:43 am
content: The line is an indicator for the mode printed above the bezel in blue.
Tektronix 1002 Freezes prior to splash screen - Page 1
Forum section: electronics / beginners

author: KE4CDR
author_rank: Newbie
timestamp: July 23, 2021, 06:09:49 pm
content: I have a Tek 1002 and it started rebooting when I would push the auto button. Now, on startup, it lights the four LEDs across the control panel and then hangs. There was no incident that led up to this problem that I can tell. It just started freezing. No splash screen or setup screen. Anyone have ideas as to the cause for this? I just need a starting point or some actual experience with this problem. Thanks in advance for any help.

author: jmelson
author_rank: Super Contributor
timestamp: July 24, 2021, 12:39:14 am
content: Open up the unit. Figure out which board is the power supply. Reseat all connectors from power supply to other boards. I have fixed a bunch of Tek scopes that had trash on the display or would not start up that way.Jon
Tektronix 1241 - Page 1
Forum section: electronics / beginners

author: Dave Turner
author_rank: Frequent Contributor
timestamp: December 01, 2013, 09:48:35 pm
content: I picked up a Tektronix 1241 a few weeks ago un-working and without probes. The idea being to investigate it without any pressure, just for interest.I plugged it in to see what would happen,having first checked to see that it was set to 250V and not 120V. Not unexpectedly PHUT!. The Plug fuse blew (but not the back panel fuse) with nice sparks approx 3 inches from the back under the PSU, - so teardown time.With the exception of 2 boards visually nothing seemed to be amiss.The exceptions are the PSU board and the Control Processor Board (CPB) It is clear that the battery backup on the CPB had corroded and leaked. It is possible indeed probable, that this leakage may have affected the PSU board.I removed the PSU, and on an isolation mat plugged it in again - unsurprisingly the main fuse blew again, and yet again the back panel fuse remained intact. So currently I'm trying to figure out where the fault(s) are on the PSU.I did notice that there appeared to be diodes (possibly zeners or germanium) soldered on the back of the board as a later update one of which disintegrated on touch. Also one of the main power caps has a sooty deposit on its outside only.I downloaded the (pdf) service manuals and can identify the parts v the schematics, unfortunately as yet I haven't figured out how to post just the relevant pages as opposed to the whole manual to poinnt out where.I have only basic knowledge of how to fault find a switch mode PSU and since the main fuse blows on plug in other than disassembling each component and testing them I'm at a loss.Any suggestions? - and yes I know it's not a simple question.cheersDave

author: grumpydoc
author_rank: Super Contributor
timestamp: December 01, 2013, 10:34:28 pm
content: If it's blowing the plug top fuse violently but not the back panel fuse I'd check:- that the back panel fuse is the correct rating- that here isn't a short in the IEC inlet.Then I'd check the EMI filter components, initial rectifier diodes and the two smoothing caps for shorts - careful as there will be high voltages potentially present on those components even with the mains off (and even though the fuses blew quickly).Service manual here ->http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_1241/Tektronix_1241_Service_Manual.pdfif you haven't already found it.

author: trackman44
author_rank: Regular Contributor
timestamp: December 02, 2013, 06:18:45 am
content: I would also check the mains power cord for shorts, since the fuse blew at the plug and not the back panel.Will

author: Dave Turner
author_rank: Frequent Contributor
timestamp: December 02, 2013, 11:22:15 pm
content: Thanks for the pointers.The power cord is a known good one. Nice point about the back panel fuse, as far as I can determine it's an original, though I'll order some more.Ok so it's desolder and checking. Going to take some time.
Tektronix 1720 vector scope - Page 1
Forum section: electronics / beginners

author: mylesoreilly
author_rank: Newbie
timestamp: October 30, 2020, 12:41:42 pm
content: Greetings!I am the proud owner of the Tektronix 1720 vector scope. The amber light/backlight for the waveform graticule information (pic attached) does not work when I turn it on, only sometimes flickers on. How do I go about fixing this issue?I would super appreciate any guidance on this matter!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 30, 2020, 10:43:10 pm
content: Start by looking for a service manual.These are often available for old Tektronics stuff.Or just open the thing and start poking around.If it's only the light, then it's very likely a loose wire or a dirty lamp socket.Sometimes the filament in a light bulb break in such a way that you get intermittent contact.But be careful when poking around. Even long after (hours) you pull the power plug there still may be 15kV or so on some parts of the circuits. The most obvious part to stay away from is the wire between some big ferrite core and somewhere halfway on the CRT tube.
tektronix 1741 waveform vector monitor - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 05, 2013, 05:20:46 pm
content: I've been offered one of these,tektronix 1741 waveform vector monitor ,what are they used for and would it be of any use to me as a hobbyist

author: SeanB
author_rank: Super Contributor
timestamp: May 05, 2013, 05:23:29 pm
content: Normally they are used to check video signals in broadcast television. They work with the standard test patterns and the chroma and colour burst signals to show up imperfections in a broadcast path like non linearity, bandwidth limiting and losses with frequency, as well as drifting reference frequencies in the originator.They are also a nice very accurate video monitor.

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 05, 2013, 05:32:03 pm
content: Quote from: SeanB on May 05, 2013, 05:23:29 pmThanks Sean, having only limited space ,think I'll leave it, I really want to save my money until I get enough for a Tektronix TDS420, which I have on my radar., thanks for telling me what they do.

author: SeanB
author_rank: Super Contributor
timestamp: May 05, 2013, 05:35:34 pm
content: Buy it if it is cheap and send it to W2AEW as a gift, he can definitely use it, or restore it.

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 05, 2013, 06:13:50 pm
content: Quote from: SeanB on May 05, 2013, 05:35:34 pmHe's just put it on e-Bay uk starting price £20:00phttp://www.ebay.co.uk/itm/190833810648?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

author: w2aew
author_rank: Super Contributor
timestamp: May 05, 2013, 08:37:03 pm
content: Quote from: SeanB on May 05, 2013, 05:35:34 pmThanks guys, but I don't really have a use for it in my lab.

author: ivan747
author_rank: Super Contributor
timestamp: May 06, 2013, 12:31:23 am
content: Quote from: w2aew on May 05, 2013, 08:37:03 pmI think nobody has a use for this at allThey are being sold on eBay for $50 -probably to pay for the freight and storage of these

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 06, 2013, 07:11:53 pm
content: Quote from: w2aew on May 05, 2013, 08:37:03 pmOK alan as your the Tektronix man thought I should let you know, I didn't even know what they were used for , until Sean said,I have my ey on a Tektronix TDS420, I think will out last me, but they still are expensive, quality always costs,i'm only interested in Tektronix I'm looking at the bandwidth, as I was once told the more the bandwidth the more use you get out of it.Maybe for a hobbyist it to much, but that's what I'm aiming for, unless there is a more useful Tektronix anyone can think of.

author: c4757p
author_rank: Super Contributor
timestamp: May 06, 2013, 07:24:55 pm
content: Quote from: ivan747 on May 06, 2013, 12:31:23 amYes, it looks quite useless to me. Specialized equipment for a technology that's on its way out.
Tektronix 200 / 300 series - Page 1
Forum section: electronics / beginners

author: dtRCasa
author_rank: Newbie
timestamp: January 21, 2015, 08:12:01 pm
content: Did anyone else besides tektronix ever make small portable DC powered scopes like the tek 200 / 300?

author: ion54
author_rank: Contributor
timestamp: January 22, 2015, 03:58:44 am
content: Right now you can get Owon brand with battery option.
TEKTRONIX 2211 CH1 1 NO SIGNAL - Page 1
Forum section: electronics / beginners

author: beanhauler
author_rank: Contributor
timestamp: November 11, 2020, 12:28:42 am
content: For anyone having a problem with a channel missing on one of these scopesOn the main board change U130 AND U180 Which are SL2364'SAlso Change U601 CA3054 and on the mainboard also U600 74LS05 HEX INVERTERBit of a job as you have to remove the storage board and also the overlay board.Also watch the ribbon cables they do not always plug into pin one on the socket itself although the PCB markings identify pin 1.The front panel has seven ribbon cables which are likely to snap off if disturbed. Check all the pins for continuity and resolder.Found an old stereo with the same ribbons internally to replace the ones that were too short.These silicon cables are expensive.I had to strip the complete machine down and rebuild it. Couple of weeks work but now works a treat.Also had to replace some knobs which are as rare as hens teeth so i drew on cad and having them printed.First batch not quite right but next batch i am hoping will do the trick.

author: tautech
author_rank: Super Contributor
timestamp: November 13, 2020, 08:34:38 am
content: Rather than in General Chat you should've posted in the Repair board:https://www.eevblog.com/forum/repair/But hey as the OP you can shift this thread there with the Move Topic feature at the foot of the page. Only you as the OP have this functionality.When you have your model for the knobs sorted post the files here:https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/
tektronix 2215 sweep mode - Page 1
Forum section: electronics / beginners

author: soldo63
author_rank: Contributor
timestamp: April 05, 2014, 05:06:50 pm
content: I am having a problem with a 2215 I am trying to get goingI have it set up for both channels and alternate mode, but will only display 1 or 2 channel sweeps not both at the same time.switching through ch.1, both, ch.2 and back. In both mode it stays in the last channel that it was in. never displays bothat the same time.can someone give me any hints?soldo63

author: w2aew
author_rank: Super Contributor
timestamp: April 06, 2014, 12:23:32 am
content: Quote from: soldo63 on April 05, 2014, 05:06:50 pmUse CHOP mode. The ALT mode is good when using faster sweep speeds. CHOP is used for slower sweep speeds.