Welcome to offkafka! On this channel you'll find videos of me at my bench using Tektronix, HP, Fluke, and other test equipment to troubleshoot and repair electronics -- sometimes successfully!
-About- I am an electrical engineer with twenty-five years of experience in the defense and aviation industries.
Nowadays there is a great way of doing calibration on your own bench - just get one, or preferably two of the reference boards built around an Analog Devices chip.. They give you nominally 2.5, 5, 7.5 and 10 V with an 8 digit factory calibration document. I bought two of them and compared them. Nearly perfect! Then I checked my Agilent 34411, 6-1/2 digit meter. Perfect agreement 3-ways within my Agilen resolution. I have forgotten the price of those references, but the two of them together were well below your stated outside service quote. Of course, you still need your 15 V DC bench supply.
Nice repair and a satisfying result. In the days when hot air guns were exotic, you could use a fine tipped pair of side cutters to remove these chips. Another thing to always check are the smd 3.3v zener diodes- a common failure point. Thank you for sharing.
Hello, I have the same measuring instrument but the 252, can you please help me? I want to replace the Kelvin clips with new ones, and cut off the old ones without thinking. I have not loosened anything on the connector and it is still original. when the connector is plugged in, two black wires come out of the right side, they are underneath each other. Can you tell me whether the red or the black Kelvin clip which is on the top wire please ? I did find in the description that the red Kelvin clip must be attached to the Hi drive, but don't know the difference between Hi drive and Lo drive with these identical cables. Do you perhaps know the solution, thanks in advance. Greetings Patrick.
Hi Patrick. I disassembled the connector. There are six contacts and two posts for each contact inside the assembly. With the plug facing away from me, left to right, the two signal wires from the red kelvin clip connector to the far left two pins (red on top, black on bottom). The two signal wires from the black kelvin clip connector to the third set of pins (red on top, black on bottom). The shield wires from both clip wires connect to the second set of pins (in between the two signal pins described above). Finally, there is a small white jumper from the second pin to the fourth, and from the fourth pin to the left screw hole of the assembly. Here is a quick and dirty diagram: i.imgur.com/tJZXdCc.png I hope this helps!
You did a great job! Throwing things away is always an option. Getting this Yammy back to work is the real value and the fact you did it gives a great feeling of satisfaction. Economic value in this case plays no role. About the loudness, it's how it works with Yamaha's. The Yamaha friends/members on Audiokarma are the most helpful people I have ever seen on a forum. They were immensely patient with me and learnt so much of them, when restoring my CA1000.
Great job and interesting to learn from you. Hope you don't mind, but you resemble Brad the Guitologist from his channel. I'm checking out your other videos as well.
Good for you! Watching this waiting for my new bathroom faucet to get here. It never ends ;). I have a 70 yr old house that had ungrounded outlets and cloth wrapped wires all the same color, black :). Hired an electrician to do all the grounding too.
Love all the “you should’ve” and “I would’ve” commenters. Hey know it alls, where are your RU-vid channel and your videos? I for one appreciate your video, keep em coming, don’t listen to keyboard warriors.
nice video, comment, never use sand paper on relays. soak some paper with DEOXIT and move it between the contacts. Sanding them like that will cause the to fail again. my 2 cents.
I'm wondering if there's a way that you could send the bad circuit boards to a place that makes new ones and ask them if they could make a duplicate of the bad boards minus the broken traces and potential other broken parts.
Very nice. It's always satisfying to bring an old amp back from the dead and hear it play music again. I miss those old devices that you could actually get into and fix. Too much stuff today is throwaway. I have a house full of these old electronics and I also like to restore them to working condition. I have everything from a 1914 Columbia Grafonola to 70's Telefunken and Grundig. I know you are doing this for a hobby, and the amp has a nostalgic value to you. So whatever time and money you spent on it was worth it. Thanks for sharing.
Great video. Glad you didn't give up on it. I don't have a wire wrap tool. I prefer to just desolder and remove the posts with wires attached. Keeps it looking totally original that way.
Just take a picture of the bad PCB, put it in a PCB or cad design program and redraw a new PCB by tracing over the picture. Then have it made by pcbway or jlpcb or one of the many others for a few dollars. You hardly need a second receiver to fix this. Buying a second unit is a major cop out.
Just had a 70um Cu 2layer PSU board made, 100x160mm came close to $60, once you take the time of "putting" existing pcb into KiCad into account, the donor receiver is actually the cheaper and quicker solution.
@@bzuidgeest Have you ever ordered a board? Have you ever designed one? I do not think so, regardless of the notion, that it would make any sense to spend more time and effort, so that you can remove and solder all the elements, once you finally get a new one made. No, there were no mistakes, not my first rodeo, every single pad, via, track, silk screen, clearance, were spot on. You've suggested it would have been BETTER to design and have one made and you are clearly wrong. Finally yes, a single PCB is a few dollars, but the minimum is 5 and unless you're willing to take a trip to Shenzhen, China to collect, you need to actually pay for delivery half way across the World. That's why I'm sure your knowledge of the entire process is based on nothing else, than assumption and advertisement.
Nice Job It is very satisfying when you can make a useful device from a mess. I typically remove the wire wrap posts and solder the wire straight to the board . the less connections the better
It looks like the loudness control makes it go into oscillation on the square wave. Faulty cap in that circuit. The power miss match is due to poor tracking on the volume pot as it's fine on max rotation of the pot. Probably always been like that!
I remember this amplifier well. It was always an entry level product. It is what it is. By modern standards you will find it lacks detail, the slew rate is poor as shown on the square wave. The mag input is also noisy. I think if it was mine, rather than spend money on the second unit I would have replaced the complete power amplifier board with something like an LM1875. This will sound better than the original amplifier, easy to fit, give better 4 ohm power. Only problem, it will not be original internally. Externally it will look the same, all preamp functions will be original. Make sure the LM is genuine not one of the many fakes from China.
I wasn't particularly married to the idea of keeping things original, but I knew cannibalizing was something I could fumble my way through. Your alternate path would be one heck of an overhaul. Very cool idea!
On the DVM option, did you check if the leads just unplug from the board inside? HP often used pins on the boards and heat shrunk sockets. LOOKS like it's soldered, but often just pulls off. I think the reason they did that aside from serviceability is that this was often a user installable option. I have a 5335A and installed the DVM option the same way. The OFL..... could be "overflow". But I'd put an external 10Mhz reference in and see if it persists. Seems a few on ebay with that same error on a regular basis.
I first thought OFL stood for overflow too. I was also thinking oscillator frequency loop or lock, maybe. I recently had this unit on for a while and of course there was no OFL message the entire time, so who knows. If it comes back I'll open it up and take a look at the connection you're talking about. I don't use the DVM option anyway, so if disconnecting it internally stops that message I'm all for it.
Donor unit came straight from an E-waste yard. Cut cord for the copper is the first thing they all do. I used to work at one. Well, at least ebay recycles trash, instead of it going in the landfill. Like me, the seller probably got it free. It's the ebay way! 👋
I'm glad you doubledown and picked up the parts machine. Of coarse that was a gamble. It made a great video on repair. Thks for taking the time to record through the repair process
Own 20 FM Tuners and 11 Integrated Amps, 4 Monster receivers so enjoyed this. Granted bottom end receiver and only $75, some Joker got inside that and ruined it, too bad for my taste. Have learned to stay away from cheap.
I got mine since 2013 . Still going . The small aligator are due to low inductance wires . On high frequency counts allot . Comparing de5000 against a proper tool Bode 100 Vector Network Analyzer for hobiest the de5000 does just fine .
I did not want to buy yet another OEM wall wart, for my DE-5000; I wanted to repurpose one. But, the DE-5000 uses an odd power input pin size. I determined that it is 1.35mm x 3.5mm (at least that worked for me. I could not find such a ready-made connector plug, so I made my own, from a bare pin. P/N 490-PPM-2-35135-S1 at Mousey. HTH.
Dissipation factor! A very important measurement..... This measurement is referring to how much DC current is passing through the capacitor! In a perfect world, a capacitor should only pass DC current until it reaches operating voltage of the circuit it's in or its maximum rated voltage printed on the side of the capacitor. There should not be any measurable DC current across the capacitors, unfortunately we don't live in a perfect world and capacitors will leak DC current, some will be worse than others, you want this figure to be as low as possible! Decoupling capacitors with a high dissipation factor will act as a load on the power supply, causing the power supply to work harder and hotter while pulling down the voltage rails for the rest of the circuit. In the case of coupling capacitors, like for example between audio stages, a capacitor that is passing DC current onto the next device in line which is usually a transistor will bias up or down depending on the actual transistor used and cause a failure which sometimes ends up being a cascading failure which takes out many components.... Most people just check for ESR, while bad ESR can cause issues, a capacitor with bad ESR shouldn't cause a failure! It's the capacitors with bad dissipation or as known by Drain factor that is responsible for delivering component failures.... I prefer to test capacitors by putting them in series with a μA meter to measure for DC current leakage, slowly bringing up the voltage to what the capacitors are rated for. Sometimes I see leakage slowly creeping in but after a short period of time sitting with the same voltage applied, the current drops and I can continue doing this until rated voltage. Note that this only applies to new capacitors! The longer a capacitor sits in your parts bin, the more it will dissipate and for longer.... They do stabilise but if the capacitor has a critical role in a circuit and you can going to use something that you have had in stock for ages, it's most likely gone into what I like to call a comma, it's going to need some time to wake up! Applying full rated voltage after sitting around unused for years is the equivalent to someone giving you the biggest slap just as you have gone into deep sleep! Not good! You too will probably blow up just like a capacitor does LoL.... It's advised on the Panasonic capacitor datasheet to reform their capacitors if they have been sitting around for a year or more.... Never reform used capacitors to use in new circuits! While if you suspect that a device has been sitting around unused for an extended period of time, before applying full rated voltage, plug the device under test into a wattmeter and a Variac and slowly begin to bring up the voltage in jumps of 5 or 10V at a time, allow the device to rest after each jump with the voltage constantly applied while keeping an eye on the wattmeter for any drastic changes, if you see a wattage increase after a jump but it slowly goes down and settles, this is a clear indication that the capacitors are either slowly waking up or they are nearing their service life expectancy.... After reaching the full operating voltage of the device, another test should be completed on another day or if possible a week later, if the device under test has returned to the same behaviour, the capacitors are bad and will need to be replaced! If not, then all is well and the capacitors have returned to provide a good service life.... For testing capacitors for DC current leakage, I use my Variac which has a full bridge rectifier that also has a resistor and a switch so that I can bleed off the charge on the capacitor under test while at the same time the bleed off resistor can be taken out of the test circuit so that it doesn't interfere with the results, an analogue μA meter and shunt to see what the capacitor is doing, and that's it! I can dial in almost all voltages that I come across.... This test procedure should only be done by competent persons! A fully charged capacitor isn't something to be reckoned with! I would advise to construct a test jig with a clear cover hinged over the capacitor on a base, I'm currently working on an idea that includes a switch that is activated when the clear lid is opened which will short the capacitor to a bleed off resistor just in case this test jig ends up with someone who could forget to flip a switch to discharge the capacitor under test and find out the hard way! Other than that, I find that it's a cheap and good way to both test capacitors and wake up new old stock... Or test old one's to see if or how bad they are! I have many different types of purchased capacitor testers but I favour the simple and possibly dangerous way that I have described above.... Capacitors Ah! You can't live with them, you can't live without them! You just have to try and understand them as much as possible..... To make your life just a tad bit less painful 😖...
Very interesting information Peter! I don't often deal with high value capacitors, but I did build a discharge wand for the times I do. Clip one end to chassis ground and touch the cap terminals and the voltage is bled off through a resistor. So far so good!
@@offkafka A discharge wand is a must! A charged capacitor is a snake waiting to be stepped on! They bite! But the fact remains that the majority of people don't understand capacitors! I have seen people test a capacitor for ESR and the measurement returned to good result but.... I could see from all the way over here in Australia that the top of the capacitor had bulged and had leaked it's electrolyte..... The person in the video said that the capacitor is good! It's definitely not good! I also saw someone else test capacitors for capacity and the results showed that they somehow had more capacity that what they were rated for.... This is clearly a dry capacitor! The capacity of a capacitor should always be just below it's rating! No exceptions! If it's over, it's bad! If it's too low it's also bad! A good capacitor should have low AC series resistance! Should have high DC series resistance and it's capacity should be as close to its own rating but never over! Stick to this and you will always know if a capacitor is good or bad! I test capacitors by stepping up the voltage all the way to their rated voltage because a capacitor can test good a low voltages... By stepping up the voltage you get to see where the capacitor is beginning to go bad, you get to see how much life it has lost! You just don't get that sort of confirmation when using any of the capacitor testers made today! It's either good or bad and you don't know why! The old Heathkit high voltage capacitor testers were great at teaching by showing you how a capacitor works when I has begun to fail..... Mr Carlson's Lab channel has done videos using these old vacuum tube capacitor testers.... I highly recommend watching it if you haven't already....
it is a very nice meter. It even beeps at you after a couple minutes if you forget to turn it of. The longer leads will influence the capacitance measurement, especially the small value's. Could you please make a comparison of much lower value capacitors, something like in the pF and 1nF; 10nF.
I really want to try this but I suuuuuuck at soldering. Every time I try I just end up with a mess of nothing works.. maybe I just can't read schematics lol
