Made me dig out my b750 which I pulled to bits 20years ago I had forgotten it was easy to work on and think I will finish it now. One of the capacitors you changed (the one at the front) has split so that seems like a good place to start.Thanks for taking the time to video this.
No working used a variac and slowly bought up the voltage then watched replaced the two capacitors which smoked. I will have to change or clean the vol pot and expect to do all the capacitors and tidy the case thanks for giving me the confidence, The b760 may be more of a challenge.
Hello, my name is Armando Addati. My receiver's fuse blows (250V AC 5ST 0.25A slow). To look for what part of the system was causing the short and do a basic plug and play test I toke the power supply off the system. I had it stand alone totally disconnected from the receiver. In fact the fuse of the power supply still blows, so my guess is that the problem is in the power supply. History: I bought the three systems in Boston in the 80's. In year 1990 when I moved from Boston to Rome, I had to convert it the receiver from 110volt to 220volt by moving a bridge into the power supply. So I did change the configuration on the power supply and it worked. Changed the fuse to the new config. The system worked until a few years ago. Then I had to move houses and I left the system in a box for many years. Now I moved to Canary Islands (Lanzarote) and in my new house I reinstalled all my parts (BB225 and B215 apparently all working). Unfortunately the receiver shorts. What can I do? Is there a way to repair it or a new power supply to replace it? If it can be repair, do you have a list of technicians in Spain or in Italy I can contact?
Hi Armando, if you have some experience with electronics, I guess you can get a spare power supply for your receiver (or even make one). If you are not sure, though, I highly suggest you bring the receiver to an expert tech for repair. There're quite a few repair centers scattered around Italy, expecially in Milan I think. Unfortunately I have never brought anything for repair, so I can't really say which is the best... Hope it helps! Ciao! Dave
@@DaveElectronics Do you think I am using the wrong fuse? is it maybe 2.5 amp what I need? the manual says 250 mA and that is 0.25 amp.... in your experience should I try a 2.5 amp fuse?
I checked the manual and it says 0.25A, so that’s the correct fuse. A 2.5 amps fuse would be way too much if the power supply has some shorted components, you could fry everything…
Thank you for another great video. I recently bought a beautiful B780, but unfortunately, it has a little problem: When I power the unit ON, I see weird partial numbers on the various displays. But after cycling through ON-OFF,s multiple times and letting it rest for a few minutes, the unit starts to function properly. Would you know what may have caused this? Thank you in advance for your advice.
hello, I have a B780 which was completely overhauled in 2016, and which works wonderfully. For a month now when I turn it on it works perfectly for 35 to 40 minutes then a fuse blows and the sound is full of distortion. I turn it off letting it cool and I can listen to it normally again for 35 minutes until the fuse blows again! what do you think could be condensation or another cause of the problem??? thank you in advance
Hi sorry for the late response. It could be a bad capacitor that is turning into a resistor, thus heating up and then shorting a part of the circuit, but I suspect there’s something else in your machine. These amps are exceptionally well constructed, but the board assembly, although very easily serviceable, means that you’ll have a ton of contacts that with time can oxidise and not make good connections anymore. They sometimes can move a little and short something too. On the unit I had there were a lot of contact problems due to bad storage conditions. In your case it seems that a component or some contact between boards or components may heat up and then short something somewhere. I would reseat all the connectors and boards and test the unit taking measurements of temperature around (even better with a thermal camera). Hope it helps!
