Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Floyd Gilmour
 
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Default Mitsubishi CS-3506R PIP Beyond capacitors.....?

Hi, I have read a bunch of posts about the capacitors on circa 1990s
Mits but this set is different from most of the posts I've read. This
one has the 930B436 PIP (no bypass?) which does NOT have the surface
mount caps and I've replaced just about all of the electrolytics in the
set, I think I only have a few BP I can still replace. I have been
battling the inverted video (no luma high chroma) on my set now for
about 6 months and it seems to get better for 30 days at a time. Since
the failures started I have also had another symptom which is a fairly
loud audible buzz not from the speakers, but from the neck of the
picture tube. I have found that if you swith the channel back and forth
several times you can get something to sync and the buzz goes away.
Reseting the power also seems to work sometimes. On my last round of
capacitors (about 30) I again have a great picture but I still get
that buzz intermittently. I have a few areas where the traces were
compromised by the acid and I've had to make repairs but everything
seems sound. I read on a couple of posts about the neck of the picture
tube actually cracking which concerns me. This set came to me used with
a vertical problem (fixed with 5 capacitors) and I only have about $50
in caps in it plus the picture is great when it works, so I definately
want to get it fixed. For anyone reading this take the time and check
ALL of the capacitors as in every section there have been many "fishy"
caps if not just plain gunk leakin'! The condition of some of these
caps was so bad, it's surprising that the crazy thing could run at all.
If anyone has any tips to get rid of this buzz for good I sure would
appreciate it. Thanks!

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There is a bad capacitor in one of the video switch circuits. The ic
and parts are near one corner of the small signal part of the board.
It has been 6 years since I saw this problem. It was a video signal
coupling capacitor as I remember.

David

Floyd Gilmour wrote:
Hi, I have read a bunch of posts about the capacitors on circa 1990s
Mits but this set is different from most of the posts I've read. This
one has the 930B436 PIP (no bypass?) which does NOT have the surface
mount caps and I've replaced just about all of the electrolytics in

the
set, I think I only have a few BP I can still replace. I have been
battling the inverted video (no luma high chroma) on my set now for
about 6 months and it seems to get better for 30 days at a time.

Since
the failures started I have also had another symptom which is a

fairly
loud audible buzz not from the speakers, but from the neck of the
picture tube. I have found that if you swith the channel back and

forth
several times you can get something to sync and the buzz goes away.
Reseting the power also seems to work sometimes. On my last round of
capacitors (about 30) I again have a great picture but I still get
that buzz intermittently. I have a few areas where the traces were
compromised by the acid and I've had to make repairs but everything
seems sound. I read on a couple of posts about the neck of the

picture
tube actually cracking which concerns me. This set came to me used

with
a vertical problem (fixed with 5 capacitors) and I only have about

$50
in caps in it plus the picture is great when it works, so I

definately
want to get it fixed. For anyone reading this take the time and check
ALL of the capacitors as in every section there have been many

"fishy"
caps if not just plain gunk leakin'! The condition of some of these
caps was so bad, it's surprising that the crazy thing could run at

all.
If anyone has any tips to get rid of this buzz for good I sure would
appreciate it. Thanks!


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Floyd Gilmour
 
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Default

Thanks! I'll check that! Any ideas as to why that would cause a buzz in
the neck of the picture tube? tia
wrote:
There is a bad capacitor in one of the video switch circuits. The ic
and parts are near one corner of the small signal part of the board.
It has been 6 years since I saw this problem. It was a video signal
coupling capacitor as I remember.

David

Floyd Gilmour wrote:
Hi, I have read a bunch of posts about the capacitors on circa

1990s
Mits but this set is different from most of the posts I've read.

This
one has the 930B436 PIP (no bypass?) which does NOT have the

surface
mount caps and I've replaced just about all of the electrolytics in

the
set, I think I only have a few BP I can still replace. I have been
battling the inverted video (no luma high chroma) on my set now for
about 6 months and it seems to get better for 30 days at a time.

Since
the failures started I have also had another symptom which is a

fairly
loud audible buzz not from the speakers, but from the neck of the
picture tube. I have found that if you swith the channel back and

forth
several times you can get something to sync and the buzz goes away.
Reseting the power also seems to work sometimes. On my last round

of
capacitors (about 30) I again have a great picture but I still get
that buzz intermittently. I have a few areas where the traces were
compromised by the acid and I've had to make repairs but everything
seems sound. I read on a couple of posts about the neck of the

picture
tube actually cracking which concerns me. This set came to me used

with
a vertical problem (fixed with 5 capacitors) and I only have about

$50
in caps in it plus the picture is great when it works, so I

definately
want to get it fixed. For anyone reading this take the time and

check
ALL of the capacitors as in every section there have been many

"fishy"
caps if not just plain gunk leakin'! The condition of some of these
caps was so bad, it's surprising that the crazy thing could run at

all.
If anyone has any tips to get rid of this buzz for good I sure

would
appreciate it. Thanks!


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Shoreline Electronics
 
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Default

Change these two caps : Look for the brown glue crud that causes strange
problems on these older models.


---------------------------------------------------------------
Text pasted from WinSTIPS 2.0
http://www.ServiceSoftware.com
---------------------------------------------------------------

MITSUBISHI CS3506R

Audio Buzz Or Whine In Audio

From Mitsubishi

Check C714 Off Pin #44 Of Ic701 For Glue, If Present Remove It ( The
glue...not the cap) And Resolder Connections. Pcb-Signal. (2.2uf 50v)

---------------------------------------------------------------

MITSUBISHI CS3506R

Bars Rolling Through Pix Vertically And Video Flashes

TV Doctor-T.O., Ca

Bad C232 - 10mf@ 50v

---------------------------------------------------------------

MITSUBISHI CS3506R

Video No Go

Sam Sieben Cet/Csm - Isf/Haa Trained

Replace C232 Off Of Pin 1 Of Ic202. Ic202 Is A Dynamic Black Level Ic And
Failure Of This Capacitor Causes A Symptom Of No Video.

---------------------------------------------------------------



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================

"Floyd Gilmour" wrote in message
oups.com...
Hi, I have read a bunch of posts about the capacitors on circa 1990s
Mits but this set is different from most of the posts I've read. This
one has the 930B436 PIP (no bypass?) which does NOT have the surface
mount caps and I've replaced just about all of the electrolytics in the
set, I think I only have a few BP I can still replace. I have been
battling the inverted video (no luma high chroma) on my set now for
about 6 months and it seems to get better for 30 days at a time. Since
the failures started I have also had another symptom which is a fairly
loud audible buzz not from the speakers, but from the neck of the
picture tube. I have found that if you swith the channel back and forth
several times you can get something to sync and the buzz goes away.
Reseting the power also seems to work sometimes. On my last round of
capacitors (about 30) I again have a great picture but I still get
that buzz intermittently. I have a few areas where the traces were
compromised by the acid and I've had to make repairs but everything
seems sound. I read on a couple of posts about the neck of the picture
tube actually cracking which concerns me. This set came to me used with
a vertical problem (fixed with 5 capacitors) and I only have about $50
in caps in it plus the picture is great when it works, so I definately
want to get it fixed. For anyone reading this take the time and check
ALL of the capacitors as in every section there have been many "fishy"
caps if not just plain gunk leakin'! The condition of some of these
caps was so bad, it's surprising that the crazy thing could run at all.
If anyone has any tips to get rid of this buzz for good I sure would
appreciate it. Thanks!



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Floyd Gilmour
 
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Default

Thanks a bunch Jeff!

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