Problems with a Sansui 3000A amp

[bobwilson77]

Hi all,
I wasn't sure if this was the right place to post this, but I recently bought a Sansui 3000A amp. I saw that others have asked some questions about these on this forum and figured I'd see if any of you had some ideas.

Long story short, I screwed this one up via a stupid mistake. One of the dial lamps was burned out. As I didn't have any of the style of lights these were I decided in the interim to wire another one in. Now- I have no clue how I managed to make such a ridiculously stupid mistake, but I somehow managed to basically run a solid wire from each of the lamp holders and thus created a short ( don't be too hard on me) But anyhow, after I did this, this caused a bank of four fuses that are each linked to an output channel to blow. Even after correcting my mistake, the fuses continue to blow. So something bad happened in there.

I have a few guesses. First of all, I don't have a schematic but from looking at the chassis it seems that each channel is connected to an output transistor and these are connected to the banks of fuses. I measured the voltage coming to the fuses, which is around 37-40 volts. So I am guesstimating the problem is somewhere in there.

Secondly, this has all of the original electrolytics and I would assume that at least some might be either bad or getting that way. The capacitance is massive on some, as in 3,000uF or something. They store an enormous amount of current because when I discharge the static buildup after unplugging, this creates a rather nasty SNAP! and spark.

Does this set contain output capacitors? Its hard for me to tell.

Anyhow, I will delve into this further tonight. But I was seeing if anyone had some initial thoughts.

[Electronic M]

There is a MUCH larger knowledge base for these on the separate but affiliated Audio Karma forums. You might want to post or just search threads there.

[bobwilson77]

Yup. I just realized I got these two forums confused, Whoops.

[walterbeers]

Most likely you blew (shorted) one or more of the output transistors. Many times it also blows the transistors driving the outputs that are shorted. Check all output transistors, and driver transistors with an ohmmeter, or transistor checker for shorts, replace all that are bad. Probablly can find ECG equivlant transistors on the net.

[zenith2134]

mine was a '68 and had the mods done by, (I'll never forget it).. "Dok Dillard's" repair shop. Used to power a couple of bass reflex cabinets with it.. and not for the radio either. it had a kickass line level portion. never tried tape head or mm phono much.

[zeno]

The good news is Sansui 3000's were common. Just
avoid the 5000's like the plague..........
Good luck

73 Zeno