Salvaging Transformers

[jleaman]

so there are 2 power amps in this amp 5 channels 2 for main and 3 for center and 2 for rear ? right.. so this proves me right.. when i get home ill use photo shop and draw it out on your pictures provided..

 

[kneadle]

I'm not sure that's right. It's early surround sound technology, so be careful in your analysis. There is no provision for a center channel, and I'm not sure how the channels were powered.

There are outs for 4 main speakers, Left and Right A&B. There are two outs for rear speakers, Left and Right.

Dave

 

[planet10]

Would you please elaborate after you finish celebrating?

Yea annoying him acting 10 yrs younger than he is... but he may be right, which creates the mystery of how the AC gets into the mains transformer (and what the purpose of the transformer on the main board is)....

in the pic i have circled two connections... if the red one goes to the AC mains connection then Jason is right. The yellow one would be the 120VAC from the wall... where did it go?

dave

 

[planet10]

oops the pic...

The black block next to the transformer on the board is likely a relay that acts as the power switch.

dave

 

[jleaman]

the yellow goes to that little tranny sitting beside it as it is the soft turn on. the amp is on but not fully on. Meaning the power amp part is off but the rest may be on. this is how these recievers work..

so.. when i get home ill outline how this is setup.

J

 

[kneadle]

the yellow goes to that little tranny sitting beside it as it is the soft turn on. the amp is on but not fully on. Meaning the power amp part is off but the rest may be on. this is how these recievers work..
J

That makes sense. When it was plugged in, it was in "Standby" mode if the amp wasn't powered up.

Will post more pics in a sec. I'm terribly intrigued by all this, and it started only as passing interest...

Dave

 

[kneadle]

Here are all the boards inside the Pioneer VSX-402, except for the one attached to the front face, which I presume is the switching module or whatever.

Let me know if you want to see one of these boards in better detail, and I'll post it.

Dave

 

[planet10]

the yellow goes to that little tranny sitting beside it as it is the soft turn on.

No the yellow goes somewhere else -- it could well feed the mains transformer (it is after the on/off relay)... it can clearly be seen on the trace side of the board where the standby tranny gets its AC.

dave

 

[planet10]

Dave,

can you take a pic of the trafo in the same orientation as post #2 but zoom out... also a pic such that the text on the top & bottom of the trafo circuit board can be seen.

dave

 

[planet10]

Also, what is mounted on the heat sinks?

dave

 

[jleaman]

No the yellow goes somewhere else -- it could well feed the mains transformer (it is after the on/off relay)... it can clearly be seen on the trace side of the board where the standby tranny gets its AC.

dave

that is what i ment. the yellow goes to the mains on the *BIGER* tranny : O )

 

[kneadle]

First, the requested angle of the tf

An externally hosted image should be here but it was not working when we last tested it.

 

[kneadle]

Now, when I first took it apart, I thought the heat sink was attached in some sort of heatsink "extended" way, never thinking that the chips were bent backwards....

An externally hosted image should be here but it was not working when we last tested it.

So I figured out how to unscrew them from the heatsink and bent them up. There are SIX chips, 2 each of these (=4)

An externally hosted image should be here but it was not working when we last tested it.

And these two:

An externally hosted image should be here but it was not working when we last tested it.

Do you want to see the board they are mounted on?

Dave

 

[kneadle]

Transformer board writing

Missed that request till just now

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[planet10]

First, the requested angle of the tf

What i was trying to see was the other side of the pic below... but when i adjusted the gamma on the pic the two bright spots turned into pins... perchance do you have a cable that connects these pins to the yellow pins on the main board?

 

[planet10]

Is the bridge on the trafo board smaller (or the same) as the one on the main board? What voltage ratings are the 2 sets of caps on the main board?

dave

 

[kneadle]

What i was trying to see was the other side of the pic below... but when i adjusted the gamma on the pic the two bright spots turned into pins... perchance do you have a cable that connects these pins to the yellow pins on the main board?

I was hoping you wouldn't ask that one. I have two wires which I certainly disconnected from something--the only two wires in the whole blasted amplifier, but I can't for the life of me remember if they went from those two pins to the two pins we observed on the main board earlier. They're still shaped so that they do fit the pins without my manipulating them; so that's a really good guess, eh?

Those pins, by the way, have the op-amp "triangle" symbol near them, identical to the symbol on the tracing side of the Tx board.

Is the bridge on the trafo board smaller (or the same) as the one on the main board? What voltage ratings are the 2 sets of caps on the main board?

dave

The bridge is much smaller on the trafo board than the one on the main board.

The voltage ratings are: 71 V and 8200 mF for the biggies, 42V 3300mF on the smaller set.

Dave

 

[kneadle]

and by "bridge," we mean that gangly-looking black thing, like a tall waterfowl, attached to the board at 4 points, with straight-line demarcations on the outside pins and squiggled-demarcations on the inside pins?

Dave

 

[jleaman]

yeah i think i'm beginning to think i'm right after all because A the whole amp does not run off one secondary. way to hi of a voltage for the amp. 2nd it costs to much to put in a regulated psu for the amp to run into a lower voltage.. so my best suggestion is to use a set of alligator clips with a inline fuse 2 amp. it is not going to blow a breaker or any thing just connect it. if i'm wrong it will blow if i'm right you can use your dmm to check the voltages..

 

[kneadle]

yjust connect it.

connect it to...? Those pins you identified several pages ago?