Advice Needed, Please! - TDA 8172

R

ricardo

Guest
Hi,

Re: IBM monitor 9527-011 FCC id IEY9527

I notice that, IC6, TDA 8172 (8AF418) (vertical deflation circuit) ran very
hot! I can only place my finger on the heatsink for no more than 5 to 8
seconds! Is this normal? Other heatsink of the same size felt ...just warm.
;-) Am not too familiar with this IC. It has 7 leads on it and nearby caps
are C75/.47K, tiny rectangular ceremic; C76/1000uf, ? volts; C77/10?uf 50
volts; C74 / 2200uf ? volts. (sorry, could not see some of the specs. on
those electrolytics)

I was troubleshooting for a jittering (shifting, left to right) image and
found the above heatsink "problem". Also the high voltage anode to CRT had
"leak" on to the sheet metal.nearby! I thought of cutting a sleeve of other
cable to cover/protect it, ...may work?

Your thoughts and advice appreciated. Thank you.

....ricardo
 
I did a HP recently , was a rebagged Tatung or Daewoo Monitor ....but your
OEM is NOKIA.

Mine had I think the Same IC, it was Phillips made, and yea it got REALLY
hot as you say, but the unit had other problems which I fixed, and unit has
been running fine since I fixed the other problems....so maybe its designed
that way?


"ricardo" <rcrc7@netscape.net> wrote in message
news:X8LTb.392030$X%5.344157@pd7tw2no...
| Hi,
|
| Re: IBM monitor 9527-011 FCC id IEY9527
|
| I notice that, IC6, TDA 8172 (8AF418) (vertical deflation circuit) ran
very
| hot! I can only place my finger on the heatsink for no more than 5 to 8
| seconds! Is this normal? Other heatsink of the same size felt ...just
warm.
| ;-) Am not too familiar with this IC. It has 7 leads on it and nearby caps
| are C75/.47K, tiny rectangular ceremic; C76/1000uf, ? volts; C77/10?uf 50
| volts; C74 / 2200uf ? volts. (sorry, could not see some of the specs. on
| those electrolytics)
|
| I was troubleshooting for a jittering (shifting, left to right) image and
| found the above heatsink "problem". Also the high voltage anode to CRT had
| "leak" on to the sheet metal.nearby! I thought of cutting a sleeve of
other
| cable to cover/protect it, ...may work?
|
| Your thoughts and advice appreciated. Thank you.
|
| ...ricardo
|
|
 
On Tue, 03 Feb 2004 10:57:59 GMT, "ricardo" <rcrc7@netscape.net>
wrote:

Hi,

Re: IBM monitor 9527-011 FCC id IEY9527

I notice that, IC6, TDA 8172 (8AF418) (vertical deflation circuit) ran very
hot! I can only place my finger on the heatsink for no more than 5 to 8
seconds! Is this normal? Other heatsink of the same size felt ...just warm.
;-) Am not too familiar with this IC. It has 7 leads on it and nearby caps
are C75/.47K, tiny rectangular ceremic; C76/1000uf, ? volts; C77/10?uf 50
volts; C74 / 2200uf ? volts. (sorry, could not see some of the specs. on
those electrolytics)

I was troubleshooting for a jittering (shifting, left to right) image and
found the above heatsink "problem". Also the high voltage anode to CRT had
"leak" on to the sheet metal.nearby! I thought of cutting a sleeve of other
cable to cover/protect it, ...may work?
Click to expand...
You're barking up wrong tree. The horizontal jitter is the horizontal
problem. What kind of jitter? whole picure jittering to one side and
back? Or horizontal size jitter? Or a noisy sides (jaggies on right
and left vertical edges)?

Vertical ICs of any kind runs hot because the heatsinks is barely
sized yet they do fine.

Cheers,

Wizard
 
Jason D. wrote:
On Tue, 03 Feb 2004 10:57:59 GMT, "ricardo" <rcrc7@netscape.net
wrote:


Hi,

Re: IBM monitor 9527-011 FCC id IEY9527

I notice that, IC6, TDA 8172 (8AF418) (vertical deflation circuit) ran very
hot! I can only place my finger on the heatsink for no more than 5 to 8
seconds! Is this normal? Other heatsink of the same size felt ...just warm.
;-) Am not too familiar with this IC. It has 7 leads on it and nearby caps
are C75/.47K, tiny rectangular ceremic; C76/1000uf, ? volts; C77/10?uf 50
volts; C74 / 2200uf ? volts. (sorry, could not see some of the specs. on
those electrolytics)

I was troubleshooting for a jittering (shifting, left to right) image and
found the above heatsink "problem". Also the high voltage anode to CRT had
"leak" on to the sheet metal.nearby! I thought of cutting a sleeve of other
cable to cover/protect it, ...may work?


You're barking up wrong tree. The horizontal jitter is the horizontal
problem. What kind of jitter? whole picure jittering to one side and
back? Or horizontal size jitter? Or a noisy sides (jaggies on right
and left vertical edges)?

Vertical ICs of any kind runs hot because the heatsinks is barely
sized yet they do fine.

Cheers,

Wizard
Click to expand...

Thank you for the heads up. The symptoms is initially erratic shifting
of whole image horizontally from left to right and back. Also, the image
is positioned more to the left to start off. The vertical left side
exhibits pincushioning as to bowed inwards. The right side vertical is
fine. At times, the image can collape to the center horizontally.
Control buttons on front panel does not help.

I first noticed the vertcal ic6, TDA 8172 heatsink was running hot and
naturally become a suspect until "techforce" and you Jason gave me the
assurance that is quite normal. My thanks to both of you.

Jason you right about the jaggies! Now the raster image has deteriotes
further. Instead of pincushioning bowed inwards on left vertical, there
are now "noises" on the vertical left side at the middle. It makes a
faint buzzing sound when it happens. Could see where the arcing coming
from even in the dark! ;-)) The HV (anode) from flyback transformer FBT
mearsured more than 27.5kv and very close to but less than 28kv!! Label
stuck on the CRT says 27kv.

Does this ring a bell? ;-)) HOT is Toshiba 2SC4288A. Could not find any
data sheet on this one.

Any suggestions or help/pointers to this are gladly appreciated.
Thank You a million.

Have a pleasant day!


ricrdo
 
techforce wrote:
I did a HP recently , was a rebagged Tatung or Daewoo Monitor ....but your
OEM is NOKIA.

Mine had I think the Same IC, it was Phillips made, and yea it got REALLY
hot as you say, but the unit had other problems which I fixed, and unit has
been running fine since I fixed the other problems....so maybe its designed
that way?


"ricardo" <rcrc7@netscape.net> wrote in message
news:X8LTb.392030$X%5.344157@pd7tw2no...
| Hi,
|
| Re: IBM monitor 9527-011 FCC id IEY9527
|
| I notice that, IC6, TDA 8172 (8AF418) (vertical deflation circuit) ran
very
| hot! I can only place my finger on the heatsink for no more than 5 to 8
| seconds! Is this normal? Other heatsink of the same size felt ...just
warm.
| ;-) Am not too familiar with this IC. It has 7 leads on it and nearby caps
| are C75/.47K, tiny rectangular ceremic; C76/1000uf, ? volts; C77/10?uf 50
| volts; C74 / 2200uf ? volts. (sorry, could not see some of the specs. on
| those electrolytics)
|
| I was troubleshooting for a jittering (shifting, left to right) image and
| found the above heatsink "problem". Also the high voltage anode to CRT had
| "leak" on to the sheet metal.nearby! I thought of cutting a sleeve of
other
| cable to cover/protect it, ...may work?
|
| Your thoughts and advice appreciated. Thank you.
|
| ...ricardo
|
|
Click to expand...
Thank you for sharing your experience. I can look for the "culprit" at
horizontal deflection circuit now. Please see my response to Jason below
for symptoms. Your help is gladly appreciated.

ricardo
 
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