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Marantz 2230 Blowing Fuse Immediately on Power Up

I desoldered all 7 wires and taped up the ends connected up the dbt (with 40watt) bulb and get no light whatsoever. Just to be sure I tested another function unit and bulb went half dim, so I know the dbt unit works. So no light is ok, or?
 
izman23 said:
I desoldered all 7 wires and taped up the ends connected up the dbt (with 40watt) bulb and get no light whatsoever. Just to be sure I tested another function unit and bulb went half dim, so I know the dbt unit works. So no light is ok, or?
Click to expand...

No light sounds normal if the transformer is working. There is no load on the secondaries , no caps to fill up and cause that light to go from bright to dim. Proceed onto reconnecting each set of secondaries, go green-test, then orange-test, then the remaining, testing in between reconnects. Probably gonna end up being the output unless of course that recifier is indeed shot.
 
The DBT light on like crazy when... blinded me. Connected greens, tested, no problem, connected oranges, tested, no problem. At the bridge rectifier I still had two wires disconnected the Red positive, and White negative. Connected the Red, tested, no problem. Connected the white, tested. BIG BRIGHT LIGHT... I notice the red and white wires from the bridge rectifier go to the large cap. Is the BR bad or can it be the large cap?

Thanks again!
 
I would replace both.
Nichicon Fine Gold caps are a good replacement for these, they are the same size and you can find them in solder-lug style for most values, which makes them a drop in replacement.
Get them from partsconnexion or michael percy audio.
Post here if you need help selecting parts.


Also, you can replace the two smaller (but still large) caps next to the biggest (power supply filter), it is a good idea to increase the capacitance of these caps, you will get deeper low bass.
 
Sir. Byrd,

Yes will replace all three caps and BR. Would love help with the correct part numbers. Will order right now.

Thanks!
 
izman23 said:
ok, I do have the fail pointer light. Just no stereo light...but I think that shouldn't be concerning...right?
Click to expand...

Stereo light would only come on after the unit is up and running but it could be burnt, who knows. As for the rectifier do you have a radio shack near by? They sell square rectifiers with 4 leads, I know when I did replacements on boat motors I used a 30 amp, way overkill but it works. They have markings for AC and +, the other non marked is the negative if memory serves. As for the caps, digikey or mouser probably sell them, just go with the same size and same physical size so they just drop in, nichicon is what I would use.


Question is- what took out the rectifier.
 
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If your DBT brightened with the red and white wires connected, you have a shorted output module. Desolder the red and white wires from one channel at a time, when the shorted module is out of the circuit, DBT will return to normal.
 
Aha! I bet on one of the PNP outputs now!! I doubt the cap is bad, but ohm it out looking for a very low reading that's steady. If it's at least halfway normal it will start low and climb.
 
I removed one of the output transistors off the amp board... tested. Bult glows dim then out. And, all my fuse lamps light up. Did I locate my problem?
 
That sounds right, the bulb will dim after a short time because the filter caps are charging.
Test the output transistor just to double check though.
 
testing the output transistor with DMM I get .60 across two C & B I think and then nothing else. I think I should have .50 at other point too. I will pull the other and test and report back.
 
Great, now you're getting somewhere! For a "fuse blower" one or both outputs are usually shorted C to E which is a zero or near zero diode test reading. Also pull out the other output and check it regardless.
 
Here are the readings for the (r) side amp output transistors
 

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