Pioneer SDP5073 capacitor gets warm

[James Sweet]

So I've been working on this nice 50" RPTV on and off now for about 2 years,
*finally* made a bunch of progress. Power supply had blown up, fixed that.
Audio amp chip was shorted causing shutdown, HV was excessive causing
shutdown, finally found a shorted transistor and now the HV seems to be ok.
Now there's a 10uF 250v electrolytic over near the flyback that gets quite
warm, this is a replacement since the original was bulged. One side connects
to ground, the other connects to the flyback and a diode nearby. Diode
checks good, I thought maybe it originally blew because of the excessive HV
but it still gets a bit warm, any suggestions? This has been quite a
project, I don't think I've ever replaced so many components in a single
unit.

 

[John Del]

Subject: Pioneer SDP5073 capacitor gets warm

From: "James Sweet" [email protected]
Date: 7/31/04 5:27 AM

Now there's a 10uF 250v electrolytic over near the flyback that gets quite
warm, this is a replacement since the original was bulged. One side connects
to ground, the other connects to the flyback and a diode nearby.

What is the DC voltage on the capacitor? It should be at or below 200VDC.
If the voltage seems ok, scope the pos lead and look for a pulse. Any hf crap
on the cap means a bad diode.

BTW, these caps do get above room temp, but not HOT.


John Del
Wolcott, CT

"I'm just trying to get into heaven, I'm not running for Jesus!"
Homer Simpson

(remove S for email reply)

 

[Leonard Caillouet]

Which transistor was shorted? I had one last year that had an intermittent
arc in the Red CRT that was causing it to eat transistors and shut down. It
was a bear to track down until I got lucky and saw it arc. I'd hang a probe
on the diode and see if it is leaky or slow. You might have some spikes
causing the cap to get warm. Of course, you might have installed the cap
backwards (I still do that occasionally), but you would probably know that
by now.

Leonard

 

[James Sweet]

Which transistor was shorted? I had one last year that had an intermittent
arc in the Red CRT that was causing it to eat transistors and shut down. It
was a bear to track down until I got lucky and saw it arc. I'd hang a probe
on the diode and see if it is leaky or slow. You might have some spikes
causing the cap to get warm. Of course, you might have installed the cap
backwards (I still do that occasionally), but you would probably know that
by now.

Leonard

I don't recall the board location and it's not convenient to yank it out at
the moment to look, but the transistor that was shorted is a TO-220 case
darlington transistor mounted on the big heatsink near the front of the
board (front meaning towards the screen when installed.) Took me forever to
track that one down, checked it several times and figured the apparent short
was the internal resistor that the nearby HOT has.


I haven't run it long enough to find out just how warm the capacitor gets,
figured it it was getting warm at all something was wrong but perhaps not.
My replacement is physically much smaller than the original, I'm hoping
there wasn't anything special about the one that was there.

 

[Leonard G. Caillouet]

I don't recall the board location and it's not convenient to yank it out at
the moment to look, but the transistor that was shorted is a TO-220 case
darlington transistor mounted on the big heatsink near the front of the
board (front meaning towards the screen when installed.) Took me forever to
track that one down, checked it several times and figured the apparent short
was the internal resistor that the nearby HOT has.


I haven't run it long enough to find out just how warm the capacitor gets,
figured it it was getting warm at all something was wrong but perhaps not.
My replacement is physically much smaller than the original, I'm hoping
there wasn't anything special about the one that was there.

That is the one that I had bad, but it also had a bad HOT. When I replaced
both and fired it up it would eat the smaller one almost immediately. Hope
you don't have this scenario. I doubt it because these CRT shorts are
catastrophic, your hot cap is likely due to something else, unless the cap
itself was leaky. Don't you just love how they designed these to be so easy
to access to troubleshoot?

Don't forget to resolder virtually every joint on the board, BTW.

Leonard

 

[James Sweet]

That is the one that I had bad, but it also had a bad HOT. When I replaced
both and fired it up it would eat the smaller one almost immediately. Hope
you don't have this scenario. I doubt it because these CRT shorts are
catastrophic, your hot cap is likely due to something else, unless the cap
itself was leaky. Don't you just love how they designed these to be so easy
to access to troubleshoot?

Don't forget to resolder virtually every joint on the board, BTW.

Leonard

Well I ran it for about 20 minutes and the capacitor gets quite warm to the
touch but not incredibly hot, the original diode was a bit leaky so I
replaced it quite some time ago with a horizontal damper diode from a PC
monitor, figured that should be fast enough, anyway one more problem I can't
figure out, the remote doesn't work, I know it's not the remote because it
works on another similar set.

 

[Bill Jr]

James,
Doesn't that model use a keyboard/IR detector processor IC?
I know the SD-P5062 does but the 5191 doesn't.
Worth a look.

Good Luck,
Bill Jr

 

[James Sweet]

James,
Doesn't that model use a keyboard/IR detector processor IC?
I know the SD-P5062 does but the 5191 doesn't.
Worth a look.

Good Luck,
Bill Jr

I sure don't see one, there's only a few IC's on the whole board aside from
the micro and I've been able to find datasheets for pretty much all of them.
I'm looking at the ANP1685 board, I believe the three large vertically
standing boards in the stack are all AV processing stuff.

 

[Joust]

Bill,
would you please drop me a mail at [email protected]
remove REMOVEME to reply.
thanks
its about a mutual friend.