Tweet
anyone out there have a cambridge 30 reverb schematic? i am not talkign about the twin... am not interested in the twin either, i need the single speaker one. the fuse in this amp keeps blowing, what should i do? anyway, need schematic, and if someone could help me with my problem, thanks!!!
-
-
Like any small amp blowing fuses, the primary suspect is the power amp IC - TDA2050. After that the main rectifier bridge. Those should be easy to spot in there.
Using the search function above, I find this thread among others. Scroll down to post #4.
http://music-electronics-forum.com/t13531/Education is what you're left with after you have forgotten what you have learned. -
thanks, i was wondering... is the 2050 the transformer? because all the circuitry tests good except the transformer... i am kinda new to this amplification circuitry so i was just wondering...Comment
-
How can you test all the circuitry without a worming transformer?
The TDA2050 is not a transformer, it is as I mentioned - your power amp IC. It is the five-leg thing on the heat sink that looks like a transistor. Says TDA2050 on it.
They happen, but transformer failures are rare. The test would be to disconnect the transformer secondary wires from the board and just ap[ply mains power to the transformer primary. If it still blows fuse, then it would be bad. I bet my lunch money it is OK.Education is what you're left with after you have forgotten what you have learned.Comment
-
okay... i am not even seeing anything 5 pronged, i only see a 4 prong and 8 prong, along with all the 2 prongs...Comment
-
nevermind... found itComment
-
okay... new question... if the 2050A is done for, it shouldn't produce any resistance should it? or would it? also c48 is a 100v 1 mf ... is this a problem?Comment
-
i wish i could think of all questions at once... yet another question... will it matter if the new 2050 is a TDA2050A or just a TDA2050? and where is a good place to buy them?Comment
-
Whatever comes out of the catalog will work. I'd try Mouser, Allied, Digikey, and any other large parts house.
I don;t know what you mean by produce resistance. None of the five legs should be shorted to any other. SHorted means very low resistance.
What is your question about the cap? I don't know if it is bad or not. Only you can tell. Does it belong there? I assume the amp used to work.Education is what you're left with after you have forgotten what you have learned.Comment
-
blown 2050 again
this time i looked at the board, so far, the only thing i have found that is missing is C78... would this be a problem in the single reverb?Comment
-
it would be a problem if the part were bad. it needs to be there for stability.also c48 is a 100v 1 mf ... is this a problem?
One very important part is the 10 ohm R84, connected to the output of the 2050. This is your stability network resistor. if it is open, your 2050 can turn into a power oscillator.
C78 looks like something in the channel switching circuit that could be left out easily.Education is what you're left with after you have forgotten what you have learned.Comment
-
how can you tell if it is open... i mean, it doesn't look like it is open, and another thing... diodes d5 and d6 don't give any resistance, so, i am going to replace them as well... and, when i installed the new 2050, it just kinda made noise and started smoking then, next thing i knew, the 2050 was cracked again... so...Comment
-
You use an ohm meter. The resistor should measure about 10 ohms.
That resistor is extremely important. Honest.
What do you mean the diodes don;t give any resistance. DO you mean they show zero ohms resistance? Or do you mean the meter doesn;t react to them at all - as if your probes were not connected to anything? Zero ohms means they are shorted, and no reaction at all means they are open.
However, using the ohms scale, your meter might not be able to turn on qa diode. It would detect shorted diodes though. That is why many meters inculde th dioed test function. But diodes are cheap, so better safe than sorry.Education is what you're left with after you have forgotten what you have learned.Comment
-
okay... found the problem... it was one of the legs from the transformer had gotten disconnected, but somehow was still feeding energy to the amp... anyway, and found out that the diodes are good, so... anyway, going to replace the 2050 and rewire the transformer back on... thanks for the help, and R84 reads 10 ohms... thanks again for the help...Comment
-
transformer
one question... where would i find a 066-CVU transformer? i have been searching but i am not able to find one...Comment
Comment