Finally a repair vid again! It's the segment I'm most interested in. Tear down&, Mailbag comes 2nd and 3rd for me. Learned some handy tricks throughout the years just by watching Dave's his approach to repairs

@svampebob007

7 жыл бұрын

the repair videos compared to the tear down are like game-play vs review videos. That's why I enjoy Louis Rossmann's videos, although he keeps it to Apple repairs it's basic electronics repair procedure. 1. Check voltage 2. Check if you didn't miss anything about the problem (ei Aux vs Probe) 3. fuck that's where you have to do all the probing and trouble shooting

The motorboating at 27:40 sounds like the WiFi beacon packets. They're (usually) sent out at a rate of 10Hz. I just confirmed with a function gen set to 10Hz @ 10% duty cycle, square wave. The cadence matches what we hear in the video.

Hey EEVblog, I worked for REI for several years on their more modern products. Very interesting seeing you play around with an old CPM. I think the CPM was one of the first products the owner and founder of the company helped to develop. The CPM was just a broadband receiver, which may not be as useful as a spectrum analyzer in today's world with electronics everywhere, but there were still a lot of customers for the CPM up until just a few years ago. It looks like the CPM has been discontinued.

@charlespatt

Жыл бұрын

One of my first REI units was the white-box CPM700 back in 1996. They constantly made improvements, switched to a black case too (that's one way to date a unit). It was replaced with a much newer unit, the "Andre", a little while before this video came out I think.

@alanmccormick6911

Жыл бұрын

@@charlespatt I've seen the Andre, still friends with a few people that work there.

@charlespatt

Жыл бұрын

@@alanmccormick6911 that's great. I'm in touch with many of them regularly. I was surprised to see the old white box cpm show up here on eevblog! I think i saw a date on one of the circuit boards as 1988!

Thumbs up for the 121GW Multimeter!

@jaccurtis5789

7 жыл бұрын

Rachel Maxwell Uses rather a lot of power, doesn't it?

@Gameboygenius

7 жыл бұрын

Depends on whether you mod it with a flux capacitor or not.

It's a licensing issue, you need to connect it to the Internet so it can check you have a valid license to use the probe.

Now ... teach us how to build one of these with an Arduino, a paperclip, and some gum!

@yurikirsanov8763

4 жыл бұрын

Arduino is much more complex than this thing!

That multimeter model number is awful suspicious considering Dave's affinity for Back To The Future ;)

@Direkin

7 жыл бұрын

Hah! I didn't even notice that until you mentioned it!

@Gameboygenius

7 жыл бұрын

I didn't understand what you were saying at first, but then I realized that that's a G, not a 0.

@mikgus

7 жыл бұрын

good catch, had to rewind and have another look

@ChipGuy

7 жыл бұрын

I know for a fact that it is no coincidence :)

@flyguille

7 жыл бұрын

that model number increases the sales by itself!, just appealing the subconscious.

love your repair videos! really shows the best way to diagnose issues in unknown devices

Not to familiar with REI products, but when we used to decom our old scanners / sensors we would change random components to render the device unusable upon purchase but still usable after repair. :)

@Guppzor

7 жыл бұрын

Just out of curiosity, what was the reasoning behind that?

@ccish8098

7 жыл бұрын

We did this for a few reasons. The big one is it would allow us to donate the hardware to nonprofit orgs as it was considered faulty and could be resold as such. Also at the time it met our Certified Destruction policy which required us to destroy equipment considered EOL or OOS. It keeps average Joe from using the equipment for nefarious purposes. The equipment could be purchased as faulty and repaired and resold as fixed or refurbished. Aside from storage devices we would try to donate all our old gear. Honestly most of the equipment is of no use to the average consumer.

@marshaul

7 жыл бұрын

Well, that would explain what Dave saw here.

@Guppzor

7 жыл бұрын

Thanks for the reply. I thought that would be the case, although I didn't consider the donation/refurb side of things.

One of your best Dave. Thank you.

repair videos are awesome sir

I really appreciate the honesty in these repair blogs. It would be easy to edit out the first 11 minutes of the video and start with your discovery to make yourself seem super-human and magically able to notice subtle things. But this goes far more in line with what I experience when troubleshooting - a lot of time investigating nothing, and then an "aha!" moment with something you thought was unrelated.

The 2.7 volt "rail" is most likely the "mid point" for the various op-amps. If you were using normal supplies, you would have +v, -v, and ground. They used 0, 2.7, 5.4 instead. Since you measured something over 6 volts for the high supply, the mid point may be off a bit, and thus the problem. I'd trace back the 2.7 volt rail to find its source and look there for a problem. Good luck.

I was taught the first step in troubleshooting: Verify the thing is actually broken. Pilot gripe "radar does not work in O.F.F. mode." (But, noting works in the off mode, duh!) Second step verify power supplies.

I do enjoy these repair videos, you share your approach and reasoning, as well as the process itself. Resistors do drift over time, so it could've been just out of spec.

Excellent episode, Great to see the CPM700 repaired. I can't wait to see how you get on with the resistor conundrum. :)

Very nice detective work.

Great one Dave! I, too, love the repair vids.

THE EEVBLOG METER!!!!!!!!!!!! 5:45

@PBGBen

7 жыл бұрын

I noticed that too :P

@EEVblog

7 жыл бұрын

That is a figment of your imagination

@davidmaiolo

7 жыл бұрын

what the hell ya'll talking about

@davidmaiolo

7 жыл бұрын

Lucas Berezy ahhh... donyk...I see it now

@kkuukkoo2

7 жыл бұрын

I think it detects some type of antenna :D

i don't remember how i stumbled on to your vids but after watching a few i love you vids they are really cool and in depth on how things work keep making more plz

great video. the repair ones are the best

Loved this - thanks!

Loving the new meter 😂👍🏻 Awesome

Miss fundamental Fridays. Don't forget about us newbies and hobbyists Dave, please.

Real world troubleshooting videos are fascinating.

Love it! Dave gets schooled by the circuit he said was so simple in the first video. I wonder if he'll balk at right angle traces so easily next time.

30:56 Never heard that part of the male anatomy called a nerd before!

Watching someone brain working is so much fun, and we got a result to boot. I think I was one of the annoying fix it guys. Repairs, or attempted repairs, are the best.

Hi Dave, I bet you dollars to donuts, someone turned up the the VCC regulator and it's supposed to be lower than 6.5v. If you turn that down, I bet the probe detect circuit starts working again with the original values.

@Ingineerix

7 жыл бұрын

And as a bonus, the battery life probably gets a lot better =)

@EEVblog

7 жыл бұрын

Nope, see my reply below.

@Ingineerix

7 жыл бұрын

Hmm, looked at all the replies and don't see anything except someone else suggesting the same thing and you also replying "see below". No biggie!

@EEVblog

7 жыл бұрын

Already tried that and: a) The adjustment range only goes down to 6V (6V to 6.6V) b) TP2 changes ratiometrically with supply voltage, and the probe gets it's voltage direct from the supply voltage.

@cedricvillani8502

3 жыл бұрын

@@EEVblog not going down a rabbit hole, (makes second video) consumer electronics and military use electron flow differently

Awesome you did decide to fix this. :) And for the solid state pinball machines I get in I always change out the electrolitic caps and the bridge rectifiers as most SS pins are 30 years old. Speaking of pinball machines I am making my own with tiny boards in it. Using Open Pinball Project boards right now that are on a PSOC controller. :) I just streamed yesterday putting another of my pinball boards together. Was about 5 hours of soldering components and wiring and pinning stuff. And I'll go to it again cuzz I am not going to give up even with the last psoc/coil test blew up the psoc. :|

perhaps it was adapted for the phone line and under certain circumstances would change back to probe interrupting tue monitoring process, therefore it was adapted to avoid that.

That new resistor has turned the bug detector into an angle-of-the-dangle detector!

I think Dave went pretty good there in repairing it without any repair circuitry diagram

Looks someone bugged the bug detector.

Good hardware debug video!

yay a repair!!!! more please!

Great vid', but my eyes popped out when the 121GW appeared at about 5:17!

Go the Zellweger tones at 26:08. The great dialup-killer.

At first i suspected the detection of AUX input was based on the AUX plugs having two poles, but the socket having 3, so two of them are bridged when the plug is in. But they actually did something completely different here.

Love the Thunderbirds t-shirt.

That multimeter is beautiful.

So it detects prosthetic body parts even at no touchy-touchy zone. 30:56

The moment it started working was magic.

THE EEVBlog METER HAS LANDED !!! Very good news, wooooooo hoooooo. After that first product crash landing this year (Eagle) I needed that to cheer me up, thanks a lot!

That's a neat device. Also stupid that you cannot use End Cards if you use Annotations.

Dave, you could save "some" time by simply reading the manual. You`ve just had it in front of your eyes :) 13:04 "NOTE: The Auxilary Input will not function if any Probe is connected to the Probe Input"

You have to let Segan hide the test bug in your house and try to find it!

nice one !

I'm at 20 minutes in the video where you find the probes detection at 2.71 volts. Before I go further, I'm going to make a guess. The Vreg adjustment should be brought down to 5V, and then the voltage levels when the probe is plugged in will shift over the proper range. That's my guess. The higher rail is shifting everything up and throwing off the automatic detection. Ok, now to watch the rest and see if I'm right. EDIT: Watched the rest. I don't expect you to want to do it, but I'm betting that if you put the 680K back in and drop the voltage rail down to 5V, it will also work. What do you think Dave?

@EEVblog

7 жыл бұрын

Already tried that and: a) The adjustment range only goes down to 6V (6V to 6.6V) b) TP2 changes ratiometrically with supply voltage, and the probe gets it's voltage direct from the supply voltage.

@moshly64

7 жыл бұрын

Is VREF is too low ? If TP2 is virtual ground, shouldn't it be half VCC ? 3.25V Maybe something is loading it down ? Also, the audio sounds distorted ? sign of DC clipping ?

@1djbecker

7 жыл бұрын

My guess: TP2 is the virtual ground, and it should be half Vcc. But the regulator circuit went wonky. The trimmer should adjust over a 4.7-5.3V range. When the regulator failed, some other part of the circuit started loading down the virtual ground to under 50%. This changes the detection threshold enough that the probe detection stopped working, but only degraded the rest of the analog section.

@marcelotheeyeman

5 жыл бұрын

I guess there's a dying MMIC in the probe. That's why it is draining less current and I'm sure sensitivity should be degraded. Tha's a typical failure with MMICs.

"Nerd Detector" thumbs up on that one , can be use as an pickup line for sure

Early in the video I noticed that the gain LCD says "high" but the gain switch is not depressed. Later around 19m into the video it is working right (low and switch not depressed). Then at 21:33 Dave plugs in the probe and it is wrong again. Maybe there is an auto detect going on there also. But maybe I am just seeing that wrong.

Nice repair video even if fault was not what originally expected...

Nice! 👍

I noticed the AUX input on the FIRST video. but I thought nahhhh, davie is too smart for that!

Anyone notice that the mast-head amplifier PCB seems to be a homemade job?

It took me a couple of seconds to work out what the "ox" input was lol

It's "Danger, Will Robinson!" not warning.

WAIT!!! You can add cards and annotations, just not annotations and end screens.

I too agree with some other viewers about the voltage rail setting. Has the device got any TIL chips in the circuit. If it does this would give a clue as to what the Vcc rail should be. I think it should be 5 volts. As it has a preset pot, this could be faulty.

What if the supply voltage was too high? 3.8 volts seems high for the micro. Drop supply down to 5v -> micro goes to 3.3 -> resistance values back in spec? Just a thought.

Perhaps it was modified to work with a non-standard probe (with a different impedence). The inclusion of original parts may have been done later out of a bin of similar units before being auctioned off as untested surplus.

Will DaveCAD get a library update for 2017?

@renoflash06

7 жыл бұрын

Probably not. DaveCAD 2017 is only available as a subscription license.

Your voice sounds really neat with auto gain on, if a bit loud.

Out of some reason, I have the bell activated and still didn't get a notification.... Great video though!

I was just wondering about that dodgy resister....could it be that it was part of the decommissioning of this detector? I don't remember if you stated the exact origin of this unit, but I would think that a "agency" that was retiring the unit would render it inoperable some how when it was taken out of service to prevent the misuse of it. But do it in such a way that it would be easily reversible if they did have to bring it back into use.

Is that new EEVBlog multimeter available yet?

I don't see those card pop-ups on my tablet. Think it must be ad blocking. Better to put links in the description, who knows what KZread might 'fix' in future. ;)

That 2.7 volt level -- Vcc/2 would make more sense given a bunch of op amps, yes? So if Vcc/2 has shifted (bogus divider?) then the comparator for probe sense would also go out of whack. A wild guess based on doing designs running op amps off a single power source...

That was fun :)

That DIP16 could be an LM13600 or LM13700 OTA, possibly used in the gain circuit?

1st rule of troubleshooting is gather information.

That thing kind of reminds me of mr. Carlson's super probe. It's on Mr Carlson's youtube Channel.. you can buy the parts and he will teach you how to assemble it and use it for electronics repair. I don't know Maybe it's a completely a different thing? It just kind of reminded me of it...... pretty cool old technology.

wonder if maybe the home made job was a prior repair for the same issue and the resistance wasnt high enough causing it to not detect

@ianc4901

7 жыл бұрын

2 resistors in parallel with different values is very strange to see. Normally you would expect them to be the same so they split the load equally.

@FindLiberty

7 жыл бұрын

Yea Ian, that's when providing extra power dissipation capacity. These two are used as a calibration adjustment using *different* standard value, fixed resistors to get to a non-standard result... I'd prefer it if one was a "low" standard value that was selected just above the desired final resistance result, and other one is a much higher resistance range *linear trim pot* wired in parallel to slightly (gradually) adjust down to the final desired resistance value. * USELESS BONUS INFO* Don't tell anyone that ~40 years ago I made a few "specially-cobbled" 75 Ohm terminators that worked the same way. They were needed to magically "calibrate" several odd video sources selected at a single waveform monitor station (used to make *precise* remote adjustments - compensating for various video router paths, short and some very long cable lengths, etc.). lol Freq compensation tricks, video delay lines and cables cut to length for timing discrete drive signals... Today, that's all as obsolete and/or specialized as knowing all about various length nails required to attach horse shoes (to a horse's foot).

more like "Thou shall look at the front panel" :D

Clearly the NSA disabled it before letting it out into the wild for the espionage enthusiast collectors. * wink, wink *

what does the pot do that is next to the aux input? maybe it is to adjust the auto input switching.

cool!!

The manual says "when there's a probe connected to the front, the Aux input will not work", so what about input detection on the probe circuit? Edit: There I wrote it, and right then you arrived at it by deductive reasoning as well.

facinating :)

Can you have a look at a rack delay called the Deltalab Effectron and maybe do a video. I have the version 3. How could I and other owners improve it so it doesn't overheat and is more reliable.

My guess is the power supply voltage drifted a little and was effecting one side of the comparator more than the other. Could have been fixed with a tweak on the voltage POT with just the right tongue angle.

@EEVblog

7 жыл бұрын

Nope, see my other reply below.

Something far more economical and portable... El cheapo CC308+ on Ebay. Used the darn thing to show a customer how their RF transmitter was interfering with their on board DC regulators during manufacturing test. Major yield problem! Made a nice video of when the cell phone chipset started transmitting (detected on the CC308) simultaneously, my cheap TDS2014 showed the LDO power dropping out! I remember a crazy friend demonstrating this on a Harrison Labs power supply with his Amateur Radio "handy talkie" in college during a lab. Wasn't funny then!

As far as I know, cards can only be added at the end of the video, in the last 20 seconds or so.

THE EEVBLOG REPAIR CURSE HAS BEEN BROKEN!

Is it my imagination, or has Dave been uploading fewer videos of late (taking into account his holiday as well)?

@EEVblog

7 жыл бұрын

Correctamundo

32:03 Could the 6.5v main regulator voltage have something to do with the threshold not being correct if someone had played with the voltage adjustment pot ?? Perhaps it was at a slightly different required voltage. BTW these are $2600 USsd on Amazon.

Could it be that they've been using some kind of custom probe there that needed the resistor change to detect?

What a smexy multimeter.....😊

Are you sure the RC circuit at 8:20 is not a reset delay for the MCU?

Video about the meter possibly?

2.5 is usually the threshold in micros...

Did they play Lost in Space on TV in Australia? I guess that's possible we got Skippy in the US of A

@kwils6685

7 жыл бұрын

But I never saw it! I'm not that old.

you didn't show us the wall adapter one!

LOL i noticed the AUX input in the first vid...but thought you'd know better so i didnt comment!

What was the measured voltage on those two resistors dave?, no where near 2.7v i suppose, The chip has to be a Lm324 or similar. You have a micro controlled meter too close to that unit, noise source?

Tear down video is coming for new EEVblog multi meter. Don't turn it on, take it apart!

Is that a new multimeter? You decide to show it?

Could you use the device to listen to the RF patterns emitted by common devices like, Wifi routers, Bluetooth, smart phone, wireless mouse and smart meter etc.

@BlackEpyon

6 жыл бұрын

Potentially, you could, but you'd have no way of identifying the specific frequency, and thus channel within the band range that it's using. I keep thinking a bug sweep like this would have been useful in diagnosing wireless VHF lav mic troubles in some of my live audio setups years ago. I was quite happy to upgrade to UHF models with switchable frequencies.

@desmondallindrallintscmint7479

2 жыл бұрын

U would. But no ID of frequency. One can find, detect and pretty much locate all forms of transmitting signals including wifi or BT etc signals …. Once the signal source is located, Its a physical search and or, then supplement and use latest modern tscm equipment to ID the signal and frequency before you disassemble the innocent microwave ;-)

I would have tried lowering the 6.5v rail, if the 2.7v didn't fall with it that alone may have fixed it.

@loughkb

7 жыл бұрын

Ha! I had the same idea. Didn't read down the comments far enough.

@mariolohajner1022

7 жыл бұрын

Right, lower that to 5V (more-logic-like level) and see what happens.

How does one repair or replace the LCD screen (leaking ink symptoms), on the CPM? Are there off the shelf LCD screen / parts available?