The oil on the old clear PVC tubing is the plasticizer leaching out. This is the same substance that "melts" hard plastics when soft PVC cables are left sitting on them for too long.
Thanks for all your superb videos and the time you take to explain issues, procedures etc. I've learned a lot and currently fixing an amp for a friend after learning the general how to from you 😊 Regards Brendan
Bias current is for the A part of class AB amplifier, working in class A at low level, thus avoidind crossover distortion. You can test if your bias current is not too low by measuring distortion at low level.
I would also assume it would be a typo for 30mA bias for each channel. Perhaps the spec is poorly written to mean 30mA for both combined. Nice job however Trevor. Always excited for your videos!
There is usually a multiplex level adjustment for the stereo decoder to kick in only when the 19khz level in the carrier is high enough. Might need tweaking to make the stereo light behave.
Using 100V caps instead of 35V is no issue....as long as same capacitance value and that they fit. That being said these replacement caps were sloppily installed, probably what the pevious tech had in stock. And the main filter caps, I would remove the old and replace with a similar diameter form-factor cap. Nice vintage Rotel.
I have a Rotel RX602 which is similar to your RX802. The power button playing up. Can switch on but difficulty switching off. Need to give a hard push with the finger. Would appreciate your expertise.
I saw that those 2 carbon comp resistors on each side of the power amp board were still there. Did you check them as you had mentioned? Enjoyed the work on this Rotel!
I enjoy seeing these old Rotel's getting the love they deserve to continue on with life. Very thorough t'shooting and problem solving. You and family have a Merry Christmas!
The manufacturers of capacitors agreed very early on the international SI units, which is why the temperatures on electrolytic capacitors are given in degrees Celsius
Nice video. I'm working on the same receiver that kept on blowing the power transistors on one channel because the temperature skyrockeded. Found out that the stabistor on one channel was fried, but on the other channel the bias voltage could be adjusted to be bang on 30mV. It turns out the stabistors are impossible to find, so one solution is to put two tN4148 diodes in series which ain't the best solution. Someone are talking about making a resistor circuit instead but there is no description to be found. Other say a green led diode painted with nail polish to make it voltage stable might work. Does anybody know what is the best solution to replace the stabistors?
I have read on some commments that people say that you can go higher on the voltage on the caps but don't go higher on the mfds to stay with the recommended? so now i am confused? What happens when you go higher on the voltage? Thank you
Really, there no harm in it, just wasteful. Those 100v audio grade caps were not cheap. The proper replacements were probably 1/10 the cost. Using caps that are wildly overrated in voltage will not form properly during their service life, not sure if that makes any difference in their performance, just sayin
Happy Holidays to you Trevor. Yes, the width is eye catching along with the color contrast of the Face plate, hard to believe 1975 (except green lighting) looks more 1980. Service Caps look good. Enjoyed the BIAS fiasco.
This ass-clown has been doing this to Trevor’s channel for quite some time. I don’t know, maybe Trevor stole his girl in junior high school or something like that. Probably should get some professional help.
Wow very nice video as I always watch your all video I must say that you are master of the master professional electronics engineer 🎉🎉 you must be rocket science 😊 and you are the best on RU-vid no one can beat you 😊the best master professional guru and merry christmas and happy new year to you and your family ps if need help I will it you know and please kindly don't forget me 😊I am from London England thank you
