SONY TC-K520 - Electronics is going crazy soon after inclusion / strange behavio

Hello
I have a SONY TC-K520 tape recorder, which soon after switching on (2-6 minutes) starts "crazy electronics". Symptoms: fading display (partial / full), previously incorrect display of the tape counter, automatic activation of "MEMORY" idt. After starting the playback, when it is "mad", the tape recorder continues to play despite being turned off by the main power switch. Only pulling the plug from the network interrupts this "suspension". I also have a second SONY TC-RX70 tape recorder, in which similar symptoms have appeared recently. Reading the posts in this topic, he concludes that such ailments are typical of the disease of the equipment of the company, after all, 25 years of operation is still good durability. Unfortunately, the posts do not have a specific solution for this state. Maybe, however, someone managed to dig deeper into the topic and solve this problem?
From a layperson's point of view, I would replace the electrolytes (aging), which only because there are over 60 items in all?
Thank you in advance and best regards.

Hello, if you have an oscilloscope, you can see which electrolytes are not what it is difficult to say to them and usually (at least in my case) electrolytes stabilize during long work. First, I would look at the voltage supplying the control system, stabilizers, etc.

Thank you for the hint. Unfortunately, in my case, it will not help me much. I am sorry, but my resource of knowledge and instruments is negligible. He treats this more as a new hobby, for the last two years he managed to restore two motherboards from the computer (fused capacitors) and a pair of Chinese led bulbs (exchange of blown diodes). He feels better in precision mechanics, but he knows how to hold the soldering irons in his hand, I also support the multimeter. Unfortunately, lack of knowledge interferes with a deeper search for a problem. That's it when it comes to me, so you understand, without giving any approximate details, it will not help much.
I am trying to further explore the topic, because I see that the same problem applies to many similar models of this company. I read several posts, among others: https://www.elektroda.pl/rtvforum/topic1930210.html, and: https://www.elektroda.pl/rtvforum/topic1349166.html. I have also found on the German website: http://www.hifi-forum.de/viewthread-185-268-24.html for information on the replacement of capacitors in the power supply system. In any case, I'm looking further, I'm sure in my free time I will be tempted to exchange them in the TC-RX70 model. Still, I am thinking about the TC-K520, someone is writing "disconnect" the transistor in the IR system. "This is a minor problem (apart from the demolition of the panel with the panel) to be soldered out, if you still know what it will be according to the marking on the tape deck. , castration of infrared control in order to "repair" the whole is a rather bad idea, and not for a long time (if it works at all.) I bet on capacitors, especially those with higher capacity in the power supply system, but it will be difficult to replace them after each such attempt. Who started this model knows what I'm talking about (it's necessary to start up everything including the mechanism and the front panel to get to the plate.) Recently, I've replaced the two drive belts, and that's just a fraction of the difficulty waiting for the board main, which runs in the housing at an angle and is inseparable from the front panel ste (unless you de-sold it).
Summarize, maybe someone of you repaired this model and could give "on the tray" which elements he exchanged ?. I know that he waits too much, but sometimes miracles happen, and restoring any device (without specific knowledge) is a great satisfaction.
greetings

Hello, there is another method for people who deal with electronics from time to time, I am a watchmaker myself, but with electronics I'm from elementary school, but back to the topic - thermal method; maybe weird but it's a topic for those who can not locate the damage in a standard way. Check which of the elements heated up after a certain time and then you can cool it, you need to buy a freezer in the aerosol, occasionally cool the various regions of the plate, of course, at intervals of time

Hello, each method is good if it has a specific effect. I will try instead of a freezer (moisture and water is an adventure with the current) to use a cool air. For this occasion, I used an 8cm computer fan connected to an external 12V power supply. Blowing in the area of the power supply on the recorder's motherboard definitely delays the "advent of the fault". Therefore, he will remove the main deck of the tape recorder (unfortunately, demolition of the whole, including the mechanism, panel / display). And what's next? Measure the power transistors, rectifier diodes ?. It plans to prophylactically replace the power supply electrolytes. By the way I bought occasionally the second identical Sony TC-K520 (damaged). I will have a pattern for connecting a tangle of cables from the board. It is a pity that no one on the forum has ever worked on this topic before, fell on amateur

PS maybe someone has the TC-K520 scheme? I would like to locate transistor on the recorder (Q ***?) About which Andrade's colleague wrote "I had exactly the same problem with my Sony TC-K520. After removing the transistor on the line the IR-microprocessor receiver stopped and I have no problems with it at present "

Hello, the freezer has been specially created for the location of damage by the thermal method, the only water that will be the condensation of it from the air "cold beer in a warm environment", of course, when you overdo it with the amount of the measure is a normal reaction

Please, service:

Thank you very much, my colleague cookie cookie for the service. If I am still able to identify this transistor on the line of the IR-microprocessor receiver on the record, it would be a small success (if the exchange of electrolytes in the power supply does not help, you can try and ultimately castration). Magical Q and three digits, oh knowledge that tends to me (as hell)
Colleague1 showed me the way of locating the fault (thermal), I used a fan because I had it at hand, and the freezer in store . In addition, these three transistors (they look like transistors - I am an amateur) were covered under large sheets of the heat sink (transistors in the middle between two sheets) and it would not be very much a "trick".

Admittedly, I will not answer which element is the one you are looking for but you can still turn the plate over and watch it under the account of so-called cold solders, it would be useful to have a magnifying glass

Hello
At the moment I have replaced all electrolytic capacitors in the power module on the recorder's mainboard - unfortunately it did not do anything. Replacing everything in a tape recorder (about 70 electrolytes) would be time-consuming and unprofitable, especially since there is no guarantee that it will help. There is a malfunction.
I would like to thank my colleague Andrei, who advised me about the number of the transistor (Q811) removed in the IR system (Sony TC-K520 tape recorder). Castration will be a "B" plan, for the time being a few more times, maybe some of your friends will suggest some sensible solution. It would be a shame to lose service with the remote control.

@wojciechkrak Changing electrolytes on the is not a repair. The more so that you can probably put Chinese bugs in there from an electronics store.

Just the right note, I watched the 25 years of desoldering, no symptoms of electrolyte crystallization. I also made a "short circuit" check with the multimeter - ok (I can do that). They look better visually than the new ones bought. Of course, I do not throw it away, put it away in the bag. I still have a second tape recorder (damaged) maybe one day I will be able to do something.

I do not have technical knowledge in the matter of repair, and it is unprofitable to give service (it will exceed the value of the same functional equipment). I treat it as a hobby, recently I "revived" the LCD monitor - it helped to replace five electrolyte fused in the converter. So why am I taking it if I'm green? I hope that someone has successfully fought this problem and may want to share the solution. Maybe...?
And by the way for the offspring and to take advantage of the possibilities Electrode gives the markings of rubber strips for the Sony TC-K520 tape recorder, the same also fit the model TC-RX70 with an autoreset (I also mentioned in it):
flat belt
original symbol
335946701
67x4x0,5mm

square bar
original symbol
335946601
22,5x1,3mm

It's time to close the topic - unfortunately unresolved. The real value of the equipment is so low that all attempts to support (repair on the website) are not common sense. The only reasonable solution in this matter was the advice of colleague Andrei. After removing the Q811 transistor pointed by him in the IR system, the device really regained its efficiency (at the expense of no pilot control). Once again, I am very grateful to Andrea's colleague and all the others who have spoken on the subject.