Realistic sta-2300 burnt bridge rectifier

I dont see any thing else looking bad in this receiver.
Is it possible the rectifier was defective, or is it likely something else is wrong.

Thanks.
Srinath.

First remove all leads, check resistance between B+ and ground and B- and ground, and between each other. Should be some resistance, cap charge and discharge, but no dead short. Then check resistance betweeen AC leads from transformer to Ac line input, should be no resistance, then use a dim bulb tester and check ac going to the bridge, if all looks good, then replace the bridge and try to start the receiver with the dim bulb tester. Hope this helps.

I'm not saying they're bad but it has 40 year old electrolytics in the PS. Even if they're good (which I'm thinking one or more probably aren't). Its time to replace them!. my 2c

Stillspin'n: You're asking me to test for downstream and upstream resistances at the 4 terminals of the bridge and to ground - of course after getting the thing removed ? OK I'll do that tomorow.

nj_phoenix: I thought that right as I picked up the thing. From his description I expected to find swelling and waxy caps. In fact I have found that in 3-4 yr old chinese kits. However - all that was dry as a bone and clean as a whistle.

Caps may have taken a dive, but that isn't the primary reason there was a volcano inside the amp I'm thinking.

Thanks.
Srinath.

Is it possible the glue holding the .047uf caps collected up enough moisture and conducted through the body of the ceramic cap to ground.

I once had a mica sheet show conductivity on an old amp like this.

Thanks.
Srinath.

you can get a used one here.. have them check it to make sure it's okay.

http://www.oaktreevintage.com/Realistic_Stereo_Parts_Units.htm

If no fuses blew then caps are probably fine.. but might ask about caps..

bink.

btw.. don't like that 2 point terminal/ soldering on the right with the phillips screw down. I went through mine and cleaned up a lot of what I'd call poor solder connect/ wire terminations.

I have em

I have new diode bridges. Pretty cheap.
The whole deal was why it blew out the diode bridge.
It blew the fuse as well. But not as spectacularly as the diode bridge lol.
Thanks.
Srinath.

Just tired parts just like any component diodes go, too. and that amp they would go pop. back from the power in those big caps!

See if it holds.. same link has the whole p.s. /rect./fuse board, too.

... (where did you get your part?)

bink;

I bought like 20 of em from either parts-express, mouser or MCM or Mat electronics at some point to pad an order for some stuff I was needing or such ...
Its also on ebay.
Cool.
Srinath.

Tested

stillspin'n said:

First remove all leads, check resistance between B+ and ground and B- and ground, and between each other. Should be some resistance, cap charge and discharge, but no dead short. Then check resistance betweeen AC leads from transformer to Ac line input, should be no resistance, then use a dim bulb tester and check ac going to the bridge, if all looks good, then replace the bridge and try to start the receiver with the dim bulb tester. Hope this helps.

Click to expand...

Trafo is reading 4.5 ohm on the secondary.
Trafo is putting out 90v AC.

The wires to the caps are reading like caps - a pretty high resistance (like 165 or something) and immediately open - like huge caps do.
I'll move on down the line and clean and test it and post.
But with the crispy rectifier bridge out of the way and all the wires capped off the safety's pull in and seem normal.
I'll go on down the line and test it before switching it on and cranking it he he.
Thanks.
Srinath.

Its in and working.
The on/off button has some weird behavior. Its crooked, something knocked it out I'm guessing. However, electrically the thing seems to not go off.
So Its crooked and goes in and out at an angle.
In Off: The button light is red, panel is lit, the input selector Led is lit, and no sound comes out.
In On: The button is lit green, panel is lit, input selector is lit and sound.

I have to check what the tuner strength meter does when on and off.
I also have no other led's, no power output, no signal strength, no tuning " >|< "

Cool.
Srinath.

The picture of what caught fire:

DO NOT MESS WITH THE TUNER.

You have a bad power switch. It's just going. (very popular amp for many probably been turned on and off 1000 times? = 2000? lol

Get a separate plug in extension with an on /off switch till you can locate a switch.. (like hens teeth and I'm very conservative playing mine, but they do come up.) don't forget to put all the switches and button in the off position and volume down every time you power up and off. (trust me on that!!)

AM FM... Fm? get a good dipole and hang it vertical outside is better.. These tuners came in tuned for long distance and local. FM mute auto lock features won't work..

I had mine hooked up to a good elevation and when you're talking about 300 miles or a good skip to Montreal or Toronto and sometimes chicago? That's when the AutoM and mute circuits really kick in to cut out poor signals.. then the signal gets lock.

maybe get another tuner and plug into the Aux. or get a decent antenna set up.

bink

Oh cool, thanks for the info.
The on/off button is crooked - is that just wear ? I can straighten it, but it seems to drift away to the angled position.
Thanks.
Srinath.

http://www.ebay.com/itm/Concept-16-...pt=Vintage_Electronics_R2&hash=item58b21dcd48

Is that the right part ? or wont work ? Where is the LED in that ?

Thanks.
Srinath.