Bridge Rectifier question

[hotscot]

The Bridge Rectifier in the power supply of my Marantz amp is physically damaged. It's a square shaped part from Shindengen, 200V, 4 amp.

Could someone with more knowledge than me tell me if I have to replace it with the exact same value? I see for example that Radio Shack have a 200V 6 amp rectifier. I just want to put something in the circuit to see if it will work.

Regards
Alan

 

[poobah]

You're fine, and thinking correctly.

You do have to ask yourself though... why did the rectifier blow? You might want to probe around on the rails and look for more shorts/failed comps...

 

[hotscot]

Probably my fault

Well...I'm embarrassed to say that at one time I took the two large caps out of the board and then replaced them..don't ask...and at that time I knew nothing about polarisation. So if I had them in the wrong way could that have damaged the rectifier?
I'm taking baby steps here

Schematic attached.

Regards
Alan

 

[Christer]

Did you replace the caps with larger ones (ie. more uF)? In that case you get higher charge currents and may need a bridge with higher rating.

 

[hotscot]

In fact...

If I'm going to stay bitten by this bug are there any straightforward guides on how to test individual components. I understand I'd need a meter.

Alan

 

[poobah]

Well,

I won't ask then... you are on the right track. I know the bigger caps opened up your soundstage and gave you fast bass...........................................................................................................................

 

[poobah]

Fess up,

Tell us what you did to the caps...

 

[hotscot]

Different values

Good question...


I replaced 12000uF 56 V caps with 10000 63 V Caps.

Should I adjust the Bridge Rectifier..I was going to use a 200V 6 Amp from RadioShack.

 

[hotscot]

See reply a few posts back..

About how I messed up. I'm not an electronics person..this is all new to me...but with all your help I'm learning fast
And I'm grateful.

 

[Christer]

Well, since you replaced with smaller caps, that is probably not the reason, although it could be if they are better (lower ESR) and the bridge was designed on the limit. However, that is probably not the cause of the fault in this case.

 

[Karakacha]

rectifier

please my friend ,as per the circuit ,the caps that you replaced could have worked though the problem could have been the generated noise due the ripple factor on the supply, but try to confirm the functioning of other components.

 

[dnsey]

If the polarity of the caps was wrong, that might well have damaged the rectifier. Unfortunately, it might also have damaged the caps

 

[poobah]

If the polarity was wrong... it may take 20 minutes or more but he caps would have exploded! You would have known!

This could be just a simple rectifier problem... but you should look for other problems first...

Ping anatech, he is an amplifier doctor of many years.

 

[richie00boy]

20 minutes! In my experience incorrectly polarised caps blow at switch on, and what a bang and mess they make!

The bridge rectifier you intend to use will be fine. I would look to increase the capacitors back to the original value of capacitance though, usually going down in capacitance is worse for performance.

 

[Cortez]

4 MBR10100 in a rectifier bridge will be enough in current
to charge a 33000uF/63V cap in the starting phase ?
With a soft-start circuit of course (relay + timing + resistor).