Hello,

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical
foldover for a few months, which went away after it warmed up. Then
one day, no vertical deflection at all. I pulled the board out and a
lot of the solder work is terrible. However, the problem seems more
like a bad capacitor -- but they all seem fine, at least with visual
inspection. So I'm not sure where to go from here.

Thanks in advance,

If the solder joints look bad -- they probably are. It would be a good idea
to clean them up, simply to reduce the chance of future problems.

"Sean Hamilton" wrote in message
...
Hello,

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical
foldover for a few months, which went away after it warmed up. Then
one day, no vertical deflection at all. I pulled the board out and a
lot of the solder work is terrible. However, the problem seems more
like a bad capacitor -- but they all seem fine, at least with visual
inspection. So I'm not sure where to go from here.

Thanks in advance,

Look for a non-polar capacitor in the vertical deflection area somewhere
around 10 uF. Try replacing it.



tm

On 3/27/2011 11:26 AM, Sean Hamilton wrote:
Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical
foldover for a few months, which went away after it warmed up. Then
one day, no vertical deflection at all. I pulled the board out and a
lot of the solder work is terrible. However, the problem seems more
like a bad capacitor -- but they all seem fine, at least with visual
inspection. So I'm not sure where to go from here.

Bad cap.

Though, while you've got your head in there, you could reflow
any joints that look disgusting (taking care, of course, not to
*add* to your problems!)

Though, while you've got your head in there, you could reflow
any joints that look disgusting (taking care, of course, not to
*add* to your problems!).

You should really remove & replace the solder, not just reflow it.

On Sun, 27 Mar 2011 11:26:56 -0700, Sean Hamilton wrote:

Hello,

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical foldover
for a few months, which went away after it warmed up. Then one day, no
vertical deflection at all. I pulled the board out and a lot of the
solder work is terrible. However, the problem seems more like a bad
capacitor -- but they all seem fine, at least with visual inspection. So
I'm not sure where to go from here.

Thanks in advance,

Electrolytic capacitors will often "warm up" and work well enough to
satisfy the circuit until they fail completely. If you can map out the
vertical signal and amp section(s) you might want to first hit some
suspect solder joints. After that is still no deflection you'll need to
scope out where your signal is lost.



--
Live Fast Die Young, Leave A Pretty Corpse

On Mar 27, 8:26*pm, Sean Hamilton wrote:
Hello,

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical
foldover for a few months, which went away after it warmed up. Then
one day, no vertical deflection at all. I pulled the board out and a
lot of the solder work is terrible. However, the problem seems more
like a bad capacitor -- but they all seem fine, at least with visual
inspection. So I'm not sure where to go from here.

Thanks in advance,

A visual inspection is not enough here. resolder all the pins on the
IC, change the associated caps, they're cheap enough and often there
is no reliable way to test them.

Also check for an open circuit feed resistor in its b+ line (probably
from the line output transformer).
Using the tv with poor regulation of the supply to the frame chip
probably ended up damaging it, so you might have to change that too.
they're not usually dear though.
-B

tm wrote:

"Sean Hamilton" wrote in message
...
Hello,

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television? I have a Hitachi TV which had vertical
foldover for a few months, which went away after it warmed up. Then
one day, no vertical deflection at all. I pulled the board out and a
lot of the solder work is terrible. However, the problem seems more
like a bad capacitor -- but they all seem fine, at least with visual
inspection. So I'm not sure where to go from here.

Thanks in advance,

Look for a non-polar capacitor in the vertical deflection area somewhere
around 10 uF. Try replacing it.



tm

Yup, my first suspect too. This cap is normally found attached to the
vertical deflection transistor electrically closest to B+. They are not
always non-polarized. On our Sanyo video game monitors they were regular
10ufd/250V. Find one that has a good ripple current rating if you want
the replacement to last...

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

On Mar 27, 3:00*pm, John Robertson wrote:
Yup, my first suspect too. This cap is normally found attached to the
vertical deflection transistor electrically closest to B+. They are not
always non-polarized. On our Sanyo video game monitors they were regular
10ufd/250V. Find one that has a good ripple current rating if you want
the replacement to last...
[...]
* John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9

It turns out I live a few blocks from to you. If I brought in just the
board, would you be able to take a look at it? You seem to be far
better equipped to deal with this -- I don't even have an
oscilloscope. I assume it would take less than an hour, since I
already did the boring part of getting it out of the cabinet. How much
would you charge for this? Reply by email if you wish.

Thanks,

In article
s.com, Sean Hamilton writes

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television?

Yes, but it's more likely to be a bad cap.

However, the problem seems more
like a bad capacitor

Yes.

-- but they all seem fine, at least with visual
inspection.

Visual inspection is not enough. You need an ESR meter.

--
Mike Tomlinson

In article
egroups.com, whit3rd writes

The capacitor is inexpensive; just replace it with a new one,
don't bother with testing the old unit.

*whoosh*

And how is he supposed to locate the offending capacitor without some
form of test equipment?

--
Mike Tomlinson

"Mike Tomlinson" wrote in message
...
In article
egroups.com, whit3rd writes

The capacitor is inexpensive; just replace it with a new one,
don't bother with testing the old unit.

*whoosh*

And how is he supposed to locate the offending capacitor without some
form of test equipment?

--
Mike Tomlinson


Just look for the 100uF at 35v cap next to the output IC. :-)

Mark Z.