dose it go into protect or just not turn on at all?

Come to think of it, is there a guide somewhere on what to change/upgrade on these things?

@@alexandruc.5128 As to soldering, i highly reccomend the videos series on soldering made by the company Pace, found here on youtube. Its called "Basic Soldering Lessons 1 - 9" by the channel (and soldering iron maker) paceworldwide. As for a guide on what to replace when doing a restoration, well there arent any im aware of, there are many schools of thought on this matter. When i made this video, i replaced all electrolytic capacitors, since they tend to try out. Or at least so i believed at the time, since learning museum level restoration and conservation of electrical equipment, i no longer just replace everything, but instead test each one, or just leave it as is, then test the circuits as a whole (listening to music through it in this case, as well as using a tracking generator and spectrum analyzer to measure the performance to find possible faults in need of repair. Some capacitors that have not been used for a long time, i generally try to reform if possible. And replace if not. Sine you will likely not have the test equipment i now have access to at the museum, you wont be able to fully judge the state of the capacitors. Thus its probably a good idea to replace all but the main filter capacitors. For the audio path i recommend either Elna Silmic II (if they still make them), or Wima MKS / MKP capacitors. IIRC, i used MKS4 for the amp shown. For the non audio capacitors i recommend Panasonic FC capacitors. They have proven themselves quite good over time. I usually order these parts from Mouser electronics or DigiKey. Unless there is distortion present after the recap, excessive noise, or the transistors don't match those in the schematics, you wont need to do much else to get the amplifier back up to full spec. The main filter capacitors (the can contains 2 internally) is a bit more tricky to replace. I still have the original capacitors in all my Optonica Amplifier, and they still measure within acceptable levels. Replacing them with a new one is difficult, as it will require putting two capacitors in a space meant for a single large one. If i needed to replace one right now, id turn a custom can out of Aluminium using a lathe, and place a PCB assembly (or insulated rod assembly, id need to measure which is better in this case) feeding through a screw on cap in the spots where the original leads would have been. Making such a thing would take some time, effort and access to a lathe, not to mention the cost of materials. A site that got me started, but pointed in the wrong way a lot of times, was AudioKarma. They do however have some nice write ups of restoration projects and how problems like the dual capacitors in the optonicas where overcome. You will end up with a functional decently working amplifier if asking for advise there as well, but the way to get there might not be the best, or fastest, but usually one will be figured out over time. Ill be here for advise, but may take some time to respond.

@@lbochtler Thanks so much for taking the time to write that reply. It actually got me thinking if I should even "restore" it at all, considering that it sounds perfectly fine and none of the components appear to have damage. In my mind putting all new things in it was like giving it the royal spa treatment :) And if I ever do it, I will make sure I can solder properly beforehand because I don't want to ruin this amp. Thanks again. Cheers!

@@alexandruc.5128 i recommend practicing to solder now, so you are good at it when its needed, rather then starting when its already needed. Use leaded solder with rosin core. I personally use 60/40 and 63/37 depending on what part im working on. The Pace video series gives good insight on the choice of solder. Avoid lead free solder, its not worth using and should not be used for anything important (a few exceptions exist, but not many). As for the capacitors, do a visual inspection of them from time to time. The cans (the round metal components) should not be bowing out at the top, nor should there be residue or liquid under them. the lable should also not be shrunk due to heat. They should look similar to modern new ones. If they do not, or some do not, they should be regarded as potentially damaged and require further testing with a LCR meter (if present), or directly replacing if not. Id need to look the circuit over again to check if there are capacitors whos failure could cause damage to the output hybrid, but i suspect there are few if any that could. Over all, i recommend you do some reading on electrical engineering and component aging and failure modes. I recommend the electrical engineering basics from the channel EEVBlog. But based on your description of it still sounding great, i don't think it will need servicing within the next few years. However, the capacitors will likely fail in 5 to 20 years from the time of this comments writing. That is the nature of imperfect components. The channel Curious Mark has some videos on recapping vintage electronics. Also, watch the video "Recapping: It's the New Bloodletting" from the channel Ray Gianelli

@@lbochtler oh definitely. I was ordering pcbs as we "speak" and breadboards as well. I already have a soldering iron (which needs a new tip) but I literally was not able to solder two wires not two hours ago. So... Definitely need practice. _definitely_ will not start learning in this Amp. As said, i love it to bits. Might start searching for one of it's big brothers.

I do indeed still have it, though its currently in storage. Ill have a look in a few days (currently very busy) and get the pinout. If i don't respond by the end of the week remind me again to look it up. (that is assuming its not at my grandparents house, in which case it might take a bit longer to look into it)

@@lbochtler Thanx , but i did manage to figure it out. I did made a power supply for it and some repairs , it works fine. For others whoo will try to find pinout : GROUND is obvious just use multimeter , and there are two power in one is for battery charge and second for PC , both will work fine on 12V and you only need one , i assume battery will be long gone like in mine. PS , remove BIOS battery before it leaks

@@AVErsiv I do have the battery somewhere as well. As for the bios battery, i suspect its already too late. on my 486DX2 laptop, i have already replaced it, im not sure if i did on this one as well. worst case i just need to repair traces, though without schematics, its a bit more difficult. Thanks for reminding me!

i am working on bettering myself, i feel like i suceeded in the later videos about the marantz amplifier.

@@lbochtler Thank you for not getting mad. I really want to hear what you say.

interesting, ill try it next time i play anniversary

I recall having done so, its been a while since i made the video. I do recall that a few things where not shot when i made the video, so its possible the bias was done but not recorded. Another explanation that might explain it, is that bias and offset are among the first things i check when doing a repair and or restoration of amplifiers. Heck, i even do it when testing amplifiers i have designed and built myself. The diagnosing for the pm350 was done long before the video recording was done. If you need help with your amp, i can try to help, though im incredibly busy at the moment so its likely to get drowned out by all the other stuff i have to do.

do you want the part number or just the general capacitor type and or series i used?

@@lbochtler Anything that will help be buy the right replacement capacitors, really.

@@Sladovsky1 i used the UKW1H682MRD capacitor from nichicon. they are now a retired part but are still available from mouser electronics at least as of writing this comment.

@@lbochtler Great, Thanks a lot.

nicht gantz richtig, sie sind für 100V gemacht. der kern hält aber das feld von 220V aus ohne zu sättigen. Toll ist es nicht, aber sie funktionieren damit.

It was DC current. The center electrode was a pointed copper wire (the tip was electrolytically etched to a point), the outer electrode was just a wire loop. As for the plasma, if you apply enough potential difference and current to an electrolysis setup it will cause breakdown of the hydrogen and or oxygen gas formed on the electrodes. This is what is seen in the video.

that dose explain things. thanks for letting me know. I knew of these chips existing but did not realize that one was in the server

I do indeed still respond to comments. Very interesting information, thank you for sharing!

Contamination of the waveguide cover likely started this. The magnetrons reflector cap had at the point in the video already become the arc starter

How is your amp now? Did you find the fault?

I will look into the schematic for you and see if i can find an Exploitation for you. From what you have described thus far its either a short in the output transistors (i don't have the schematic committed to memory anymore, so this is based on my experience in amplifier repair and design), a bad power supply capacitor (the big ones). However it seems likely is a short circuit in the output transistors. Check those with a multimeter on ohms and see if it reads below 1K ohm between any of the transistors terminals. Ill try to get back to you regarding this, if i dont respond in a few days notify me via comment again, since that likely means i forgot about it due to the amount of workload im currently under.

ok, so correct me if im wrong, you English isn't the best, thus the clarification. The experiment you are performing is to place a copper coin into a mixture of water with the fabric whitening agent "ujala colour remover" correct? Since i have not yet found the MSDS for it, i will have to work based on the composition of similar products. there are a few things i could be, that is creating the white coating. With just one experiment it is hard to determine what it is that has formed. my first guess is Copper(I)Chloride, as it is a white, mostly non water soluble salt of copper. This can be created by the bleach present in the water. To confirm if it is copper(I)chloride (CuCl) you would need to place the washed coated coin into hydrochloric acid, or in water mixed with sodium hydroxide (drain cleaner). If placed in the hydrochloric acid, it should stay as it was and not dissolve. If it dose, then it is either a salt of a weaker acid, or an alkali salt. If placed in the Sodium Hydroxide solution, it should dissolve away, if it dose not, then it is a salt of a stronger base then sodium hydroxide. If placed in a solution of Sodium Carbonate or Bicarbonate (washing / baking soda), and it is a chloride, it should slowly dissolve away to form a brown precipitate in the water. If it dose not then it is an alkali salt of copper. With the results of the above experiments we can narrow down what you are looking at. Once we have identified what it is, we can then determine the reaction that formed it. Without more information there are just too many possibilities.

a few fun overkill options (more expensive and time consuming then its probably worth) are the fallowing (in order of feasibility): -placing the coin into a secondary ion mass spectrometer -placing the coin into a electron probe microanalyzer -placing the coin into a Scanning Auger Electron Microscope -using reflected light spectroscopy and or ramen spectroscopy, referencing against a known pure sample of the possible compound. The above will determine the definitive composition of what ever the white stuff is. Though its far faster and easier to do it via analytical chemistry as described in the below comment. I mention the above mainly because they are interesting subjects to read into

@@lbochtler sir if u don't mind can I get ur contact details..

Sir I AM not hable to understandable can u tell me short... Formula

@@uls345 i do not have enough experimental results from you to identify it. There are too many possibilities. I described a method by which it can be identified in a previous comment. Perhaps try using google translate if English is not your first language, it might be good enough for you to understand.

i dont understand what it is you want to know. perhaps rephrase it?

i assume you want the name of the chemicals used, as well as their reaction. I should probably put that in the description at some point. Basically the input are Copper(II)Oxide and Ethanol. They form Acetaldehyde, watter and copper CuO + C2H5OH ---> Cu + C2H4O + H2O

@@lbochtlersir anti iron camical name please Sir

@@Praveenkumarkn7510 you want to turn iron oxide to elemental iron, and would like to know the chemistry involved?

@@lbochtler sir camical name

@@Praveenkumarkn7510 if my assumption is correct, then you can reduce rust back to elemental iron by means of hydrogen. One method is to heat the rust under hydrogen atmosphere. The other more safe and easy options is to use an acid such as phosphoric or hydrochloric acid. careful with hydrochloric as it will start to dissolve the iron as well, but much slower then the rust.

pro

I can try, though without access to the amplifier its self it is a rather difficult task. I am currently downloading the schematics to take a look. First off, some diagnostics questions: - Is there a popping sound heard from the speakers when the amplifier is switched to them? If yes, disconnect speakers IMMEDIATELY else damage to them may a occur! - is there a smell? - is it present on both channels, or just one of them? - is the distorted sound (assuming no pop is heard when engaging the speakers) effected by the built in Equalizers?

Thank you very much for your reply.have to say tho mate.you put the word pro in professional.such quality in your work.amazing....there is no clicking or strange noise coming from my speakers..have also tested the speakers to illiminate those as the problem..there is a warm burnt electric kind of smell tho....its like i need to turn the volume up full blast to hear anything and it comes over like a radio channel not tuned in correctly..kind of staticy.i know its not the best of situations for me to be asking advice thru messaging but any help is very much apreiciated

Also.1 set of speaker channels doesnt seem to work.only one side

@@waynegwayneg5159 OK, assuming that the equalizers do not appreciably change the sound, there is a rather good chance that the problem lay within the preamp power supply. Do you have a volt and or multimeter? If so, check the voltage across pins 8 and 4 of opamp QE01 located on the main circuit board around the front left area. (front referring to the control panel). Pin 1 on the opamp is designated by the small circular cutout on the package. The pin to the left of this, is pin 1, the one to the right is pin 8. Assuming you do not have an oscilloscope we will have to resolve this by a process of elimination. The voltage measured across the above mentioned pins 8 and 4 should be around 30V DC, if this is not the case, measure from pin 8 to the chassis as well as pin 4 to the chassis. The voltages should be 15.9 and -14.9 volts respectively. If one of these measured anything deviating more then 1 volt from the above figures the problem lies within the power supply. I would suggest that you check the voltage across Q818, the zener diode located on the top right of the main circuit board. The voltage across this zener diode should be approximately 16V. If this is not the case, replace this diode with a 16V 500mW zener diode. The original part number is HZ16-A2L though any 16V 500mW zener diode will work. For further repair report back the findings from above.

Hi...me again.....hipe you are well..thankyou again....ive just got back from a local repair shop that i took the amp to. Basically i had to read off the last message that you sent regarding checking across certain positions with the voltage reader..they all came back to be the correct voltage ect...after checking those things he basically told me that he wouldnt be able to fix it for me because i dont have the manual with wiring diagrams for him work from.also i could end up throwing loads of money at it for no reason...me personally want to keep it because of sentimental value and quality.just wondered what you could sujest.sorry for taking valuable time up