toshiba CX28400


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toshiba CX28400

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chipset
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Oct 17, 2010, 5:04 PM

Post #1 of 12 (1231 views)
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toshiba CX28400	Can't Post

This set is 1990. Chassis number TAC9005. Been away from this stuff too long. TV loosing vertical.
Upper half stretched up and lower half OK. Caps. are drying out in the Yoke curcuit. I think they are all the
220's. after 5 minues picture is normal. Anyone remember the repair ? Most of my work used to be on
computer moniters. I'd leave my tv to Albert. He has now retired. Thanks in advance.
Greg.

Ron.M
Veteran

Oct 17, 2010, 10:51 PM

Post #2 of 12 (1224 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

chipset;....
You ex car mechanics are all the same ......... Wink

....
Now you work on computer monitors ????... Shocked

...
OK..... Smile

...

Quote

Caps. are drying out in the Yoke curcuit.

NOOooo , sorry...Yoke circuit sounds fine.....

Do you know where the Vertical output IC is on the chassis ???
IF so post the name of it.... IF you can see it....
You have a bad cap in that circuit...
Not hard to find & pinpoint....
Cheap repair....
Could NOT locate a free service manual to download...
The cap could be a 1~4.7 mfd to a 220 mfd cap...
Please do not get rambunctious & start wildly checking parts...
There is a proven method to nail this....
Do you have a ESR meter ????
Do you have/can get any electronic freeze spray ???
Not a requirement , but can make things easier....

Quote

TV loosing vertical. Upper half stretched up and lower half OK.

Need to clarify...If you are losing vertical , pix will be black (shrunk) at top &/or folded over on itself...
IF upper half is stretched up , that's a different deal , but , still a vertical output problem....
Which is it ????

Post back & we go from there....OK....THANKS.... Sly

....

BTW;...Does the name "chipset" have anything to do with RCA products ????

Later....Ron.M.... Cool

.....
Veteran & Retired TV technician

(This post was edited by Ron.M on Oct 17, 2010, 10:53 PM)

chipset
New User

Oct 18, 2010, 12:26 AM

Post #3 of 12 (1218 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

yes the upper half is streched not black. 4.7 rings a bell. Same system moniters use. Chipset is the
video,audio,and the " talk " between the mother board, ram set, i.e.d ports,and usb ports. I did build and
repair computers back then. Now you just throw them in the trash and buy a new one. I do have an ESR
but not as good as i'd like. Freeze spray ? I'm an H.V.A.C. tech. I have about 80 lbs. of the stuff. R22.
It boils at -44F.

Ron.M
Veteran

Oct 18, 2010, 12:53 AM

Post #4 of 12 (1213 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

chipset:....

I need a clear answer to this;=>....
""Do you know where the Vertical output IC is on the chassis ???
IF so post the name of it.... IF you can see it"""....

Quote

I do have an ESR but not as good as i'd like.

As long as it works & you know how to use it....

I'm not familiar with the type of freeze you use in car or home AC units...
It used to be Freon , now it's something else (R22 ?)....
The electronic stuff looks like this;=>....

http://www.mcmelectronics.com/...eeze%20spray&T=R

You'll see a small nozzle for a plastic tube you insert to get a thin spray....
Does any of your 80 lbs have that type of nozzle ????

IF not , a can would do you a world of good.....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

chipset
New User

Oct 18, 2010, 1:45 AM

Post #5 of 12 (1207 views)
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Re: [Ron.M] toshiba CX28400 [In reply to]	Can't Post

I do not know where the vertical IC is. Haven't opened the system. Yes it's the same thing. R22 is
freon ( Dupont ). The same stuff you guys pay $6.00 for 6 oz. but your stuff used to be R12. Now with this enviorment shit it's R134A. It boil at -15F. As i said it's been a long time. I know where they hide the
vertical IC in a monitor but in a T.V. it's differant. I know T.V. guys that will not think of repairing a monitor.
If it's a multi sync multi scan god help you. That I.C. is the size of a AA battery flattened to 1/4 inch.
3 times as complicated. Thing is this tv is 20 years old. Problem is the picture tube is strong. Might just
retire it to my man cave in the garage. I can get a new HDTV 40 inch for $725.00 Canadian. One thing is
my toshiba lasted 20 years without a problem. Good Set ? Good product ? Go figure.

Ron.M
Veteran

Oct 18, 2010, 5:33 PM

Post #6 of 12 (1192 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

chipset;....

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Haven't opened the system.

Well , let's start there....Open it up..... Unsure

....

Quote

I know where they hide the
vertical IC in a monitor but in a T.V. it's differant.

I don't think it's that different....I have faith that you will recognise it.....

Quote

I know T.V. guys that will not think of repairing a monitor.

I'm one of the guys that has worked on a few (CRT types)...Not that big a deal....

Quote

Thing is this tv is 20 years old. Problem is the picture tube is strong.

You'll NEVER see that kind of quality again....These new LCD , LEDs & Plasmas are not holding up near as long....

How about this;=>...

Quote

http://www.mcmelectronics.com/...eeze%20spray&T=R

You'll see a small nozzle for a plastic tube you insert to get a thin spray....
Does any of your 80 lbs have that type of nozzle ????
IF not , a can would do you a world of good....

IF you don't have a can like this , would you be willing to spend the few bucks & get one from a local TV shop or supplier to fix this TV ????
TV could last another 20 years .... Wink

....

Later....Ron.M.... Cool

....
Veteran & Retired TV technician

mel
Veteran

Oct 18, 2010, 10:21 PM

Post #7 of 12 (1186 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

I don't have the schematic for that specific model but the info that I have for a similar model indicates that C301/5/6 and/or 8 are the likely culprits. I usually just replace them all to save potential future problems. You should not to continue to play the set with this condition because it creates the potential for blowing the vertical IC.

chipset
New User

Oct 20, 2010, 8:35 PM

Post #8 of 12 (1174 views)
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Re: [mel] toshiba CX28400 [In reply to]	Can't Post

Thanks gentlemen. Thanks Mel. I got her. couldn't find C301 but got the rest. Found R301-D301-IC301
but no C301. Well picture looks good. Had to channel surf for awhile because most everything is now
Letter boxed. Couldn't tell if i made it worse or not untill i found cartoons. Still has a slight shift to the right
but not noticable unless the channel guide is brought up. Yes i did fing the Vertical IC. It just jumped up
and there it was. Been awhile. C305-1uf came in at .4 C308-220mf came in at 187. 3300 was acceptable
but changed it anyway. Didn't get the anode bite. Must have done something right. I hate the bite from
a moniter. 37,000 jolts in the cap. They hurt. Thought i'd better get at it before i had too many beers.
Mind you that is when i do some of my best work. Had forgotten how heavy that blood tube was.
I can't lift my 32 inch. well i can but not a good idea. I had that one repaired 3 years after i bought it.
Panasonic 32" CRT. Same problem but the upper half did collapse,black. CT 32D11CE. 2002. still has a
beautiful picture. It's on 18 hours aday. 7 days. It's a good feeling you actually fixed something and didn't
F%#@ it up. I still have to look for my solder joints and letters on the board with a 10 power jewlers glass.
Getting old. Thanks again fellas. Maybe i'll resume the hobby ? Next stop Flat panels ?
greg

jts1957
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Oct 21, 2010, 2:39 AM

Post #9 of 12 (1171 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

Start by fixing this one:

-------------------------
Location: Far, Far Away

chipset
New User

Oct 21, 2010, 3:04 PM

Post #10 of 12 (1167 views)
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Re: [chipset] toshiba CX28400 [In reply to]	Can't Post

Looks better than some of the cheap drugs i was on. Cracked screen ? Looks like a laptop
screen i saw that was frozen. Think i'll pass.

(This post was edited by chipset on Oct 21, 2010, 8:27 PM)

darstr
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Oct 21, 2010, 8:37 PM

Post #11 of 12 (1161 views)
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Re: [jts1957] toshiba CX28400 [In reply to]	Can't Post

Thats art deco right? Hmmm

mel
Veteran

Oct 21, 2010, 11:18 PM

Post #12 of 12 (1159 views)
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Re: [jts1957] toshiba CX28400 [In reply to]	Can't Post

Looks like somebody broke it.

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