This Proton receiver operate the same way has a Nad.

Thank you for the video, I found it most educational. I liked seeing the four different configurations. What size isolation transformer are you using? Do have a recommendation for as to a minimum and maximum size to look for? Thank you.

Up here in Canada I had an Adcom. I really found the sound cold and uninteresting. Well built. Perhaps even very well built. Just I look at sound from being expressive and yet delicate. I mean I could push the amp to it's max and it had no distortion. One other amplifier circuit was not as simple but was effectively more robust while able to produce very high quality sound. Rebuilding a damaged amplifier takes knowledge of more than reading a schematic diagram. Understanding

Do you take new projects? I have a Spectro Acoustics 210 in working condition…no obvious distortion…but I’d like to get it “recapped” and with new sockets as you did on this one. At the least, can I get a list of the parts you purchased and replaced?

Excellent teaching video.

Hi thanks again for the video it’s very helpful I am going to start repairing av amplifiers and tube amplifiers and before I even start to repair amplifiers I want to get a setup like you have and be safe in doing so can you recommend All the equipment I would need to be able to put together on a bench permanently mounted like all cables and thicknesses and ground wires and the type of bulb holder and switch onto the bulb holder and a Schematic of the equipment on how it should be put together then I can safely work on the amplifiers thank you Mark

It's not only RIFAs blowing up though. I've had old 80s WIMA X2 ones (silver color) release phenomenal clouds of white smoke just as well as the RIFAs do. Which makes me wonder: Which brand/model safety caps are actually safe to operate after 40 years?

Erik's work bench is so clean & organized he's a real professional tech. And Thx for uploading these videos for us.

This might be heresy, but when restoring an instrument for use, leather cases and handles that aren't in pristine condition are something I just let go of - impossible to really clean most of the time, and mold magnets....

Might be prudent to insulate the inside of the battery lid, and even the bolts - if any of that retrofitted battery wiring shorts or arcs to the case, it could result in a live case when measuring high voltages.

Which of those is C3 in your (anyone's)

Just discovered your channel. This ans. All my questions about how to set up a safe work bench.

Useful video. Might explain current is measured in series voltage in parallel when you go the 'leads' explanations.. Wise about pulling the tubes....sometimes they twist and break the spigot....repairable with superglue but still a nuisance.. Make sure the electro's are discharged before checking with multimeter....and I can't abide digital meters for general work too 'fidgety..I prefer analogue. ' As the demonstration progresses..if not viewer really experienced there's a risk with exposed B+ levels on terminals whether bias of other... The demonstrator takes risks around terminals and resistors which will be greater than for you... A couple of the resistors were too far out in my unit .also the 1K shows signs of overheating even though reading 1K on meter. Unfortunately my set (yours too?) was built with component wires curled around tags than all later soldered....damned nuisance when replacing components...if doing 'properly' and not cutting the leads and soldering new component to old leads. ...we don't all have solder suckers...If one goes that way wind the new component leads into a spring-like appearance doe a few mm (or say about 3/16th inch) as a close diameter fit to the cut lead. Slide over and solder .It's neat and secure. I think I'll use a voltage limiting cct independently...This is the second supply which has blown an electro with runaway voltage....the other was a BWD...with expensive pots....one of which blew also. The BWD is more complex than this unit and uses early model IC's. BTW you talk about ';soddering' in English the word is solder...with an "L" not 'sodder 'as in French. Pronunciation is soul-der. I wonder why Americans pronounce it as 'sodd'...('off with the pixies' distraction!!) Ok on th 470K resistors and equal value...but they are +/- 10%. The designer took that into account...I like perfection too but one can get 'neuro'...and the values will change again over time and maybe not change equally. Did you adjust the calibration pots?.to show how it should work?

Can you do a video explaining the load meter

I have a Soundcraftsmen EQ that also used the 4136 chip. It's basically a quad 741. It's an inferior sounding low-fi chip. That EQ used only one per ch. So I replaced them with LM837's using a DYI adapter (daughter) board.

if they were TRW sockets always replace them

Oh I remember also in the early 1980s I had to replace the sockets for the ICS because they use those really crappy CA sockets that developed a four connection. The symptom was that the equalizer began oscillating like this one is.

I bought mine new in 1976. I got the 210r rack mounted model. The potentiometers got pretty scratchy after about 4 or 5 years. And after 40 years I had to recap the unit.

Perfect👍

*5* Stars easy to follow along and learn how to repair.

Excellent

Good Job.

Kilroy Was Here

Excellent troubleshooting and repair skills.How do you match a complimentary pair of NPN and PNP power output transistors?Thanks in advance.

I just repaired my 5334B just before watching this. One of my 0.1uF Rifa caps had seemingly violently exploded, it literally looked like it was hit by a bullet.

So many gems in this video! Thanks for sharing knowledge and expertise. Well done.

Is this similar to the MEP803A regulator?

Hi Erik, You have explained everything in great detail in your video and you would be the best Electronic Tech on this planet. Thank you very much for all your time.

Bad design? They only offer a 2 year warranty.

Bad design? They only offer a 2 year warranty.

Hi from Norway! From your first name, are you of Scandinavian origin? That is a very versatile, and complicated power source, must have been very expensive new. Nice!

Great video, just one remark: Y-capacitors are often even more safety critical than you described. Nearly every class-II SMPS uses Y-capacitors between the primary and secondary side of the transformer to surpress EMI. If a Y-capacitor fails in a class-I device - like you have shown in your sketch - then usually the failure current is going through PE and the RCI or even the circuit breaker trips. But if a Y-capacitor in a class-II device fails, then you have mains voltage directly on an output that usually is not earthed - e.g. on the output of your smartphone charger. An electric shock is more or less unavoidable in that case.

I worked on an Oscilloscope in high school that had 48 tubes besides the crt. Tektronics made it Motorola donated it. I found out why Dad told me to use the high voltage probe for voltages over 300 volts. Ouch! 😅

Terrible device?

Great Video! Thanks for sharing your knowledge! Is that fuse that is mounted across the selector switch factory or an after-market repair/modification?

Wow. Module is quite quality

Great video and well done trouble shooting!

Great Erik .

Really very helpful diagnosis !

Great diagnosis! Lambda made some great supplies

Excellent !, I love your videos, thanks .

Thank you for another great video! One minor note for someone trying to replicate the high frequency AC voltage measurement: The 34465A is specified for up to 300kHz, but most hand-held DMMs are much more limited, e. g. Fluke 179: 1kHz, Fluke 87V: 20 kHz, Brymen BM789: 100 kHz. An isolated oscilloscope (consider max. voltage) or a HV differential probe can help here. One more thing: Did you happen to measure the waveform/peak voltage at this cap afterwards? Would give some peace of mind that the selected capacitor with its voltage rating is properly chosen. (I'm pretty confident it is...)

Hi Eric, interesting and informative video; thanks. I see the logic in arranging the items as you do on your bench and indeed i used to have mine configured in the same order but, quite frankly, I couldn't put up with the noise. Since moving house, I now have the space to move the 'lab', such that it is, from a very drafty, cold garage to a nice warm ground floor room in the house. Whilst setting up, I decided I needed to do something about the 'growling' noise emanating from my toroidal iso-transformer: it really is quite offensive and not the sort of thing one would want next to their ear for any extended period!! I it put the first in the chain originally since it is a 2kVA unit and my mechanical engineer's logic suggested it would be better to put the 50VA variable behind it. Anyway, long story short, when I started the new setup I reversed the positions and had the variac first in chain. Lo & behold, the horrendous 'growling' ceased. It does return to a degree when I give it full mains voltage but below about 90-95% full power it is almost unnoticeable now, though I do not have the bulbs in circuit yet. They have always been last in the chain. Any ideas as to what the cause may be? I surfed the 'net' for hours trying to find clues as to what aggitates the toroid enough to make it angry, though without noticeable success. It does seem voltage dependent but I am at a loss with this one. Any advice or suggestions would be much appreciated as I do not like being 'growled' at by 240 of His Majesty's finest volts. Keep up the good work. 👨‍🎓

Is there a simple analog soft start circuit?😅 plan to use for angle grinder

Good job Erik ! Imagine measuring 4000 volts with the meter, who does that ? Do you know where these meters are still professionally used ? As someone mentioned in the previous video, they are still available on the market, made where !

What are these things used for?

Thanks!

so I assume your secondary stage of the iso transformer has no ground reference , therefore the variac will have no ground reference and neither will the dim bulb and device under test. so besides placing two ground probes on the dut which can cause voltage potential if not in the same place, are their any other vunerabiltys , can yo be shocked by touching the metal casing of the Variac as it is not grounded or something of that sort. thank you.

Your 'test cord' has a name. It is called a suicide cord. It should have a fuse wired in it!!

You only had chan 1 selected on your scope