Toshiba CF30F40


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Toshiba CF30F40

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john916
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Apr 19, 2006, 2:44 AM

Post #1 of 9 (1385 views)
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Toshiba CF30F40	Can't Post

Hi,
I'm having some vertical problems and occasional horizontal problems with this set. I don't have a schematic. I'm losing some vertical (picture height keeps changing) and some (to a lesser extent) horizontal size. Would this be a bad cap or caps? Or am I looking for a failing H/V output transistor? If so, could anyone point me in the general direction? Many thanks.

John

techchris
Veteran

Apr 19, 2006, 10:55 AM

Post #2 of 9 (1375 views)
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Re: [john916] Toshiba CF30F40 [In reply to]	Can't Post

horizontal output transistors usually fail permanently not intermittently. look for bad solder joints in the power supply or flyback transformer areas first. you could try using an INSULATED plastic stick to prod things to see if you can induce the fault to appear which will indicate a poor connection somewhere.

Paulpablo
Enthusiast

Apr 19, 2006, 6:11 PM

Post #3 of 9 (1371 views)
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Re: [john916] Toshiba CF30F40 [In reply to]	Can't Post

Change C305(2.2mfd@50v) for your vertical problem.

mel
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Apr 19, 2006, 11:40 PM

Post #4 of 9 (1365 views)
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Re: [john916] Toshiba CF30F40 [In reply to]	Can't Post

Recently repaired one of those. It was a cold solder joint on one of the pins of the vertival IC making intermittent contact.

john916
New User

Apr 20, 2006, 2:21 AM

Post #5 of 9 (1361 views)
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Re: [Paulpablo] Toshiba CF30F40 [In reply to]	Can't Post

Thanks. I had a 1.5 on hand and put that in. Vertical is much better. Any idea on caps in the horiz circuit? Any one have a schematic for this set? What ref # is the horiz circuit?

I plan on replacing a couple of other electrolytics in the vertical circuit. Thanks again.

John Smile

john916
New User

Apr 20, 2006, 2:24 AM

Post #6 of 9 (1360 views)
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Re: [mel] Toshiba CF30F40 [In reply to]	Can't Post

I looked around (not sure exactly which IC is for vertical), but didn't see any cold joints. Touched up a few around the FB, esp. a couple of resistors and a diode that appear to get warm.

Sill have an intermittant in the horizontal section. I need to get a stronger signal into it to be sure. Wish I could find my old Heathkit bar dot generator..... Unimpressed

Thanks,
John

mel
Veteran

Apr 20, 2006, 9:49 PM

Post #7 of 9 (1353 views)
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Re: [john916] Toshiba CF30F40 [In reply to]	Can't Post

You can go to www.samswebsite.com and download the Efact #4025 for $22 or you should be able to find the Photofact at your local library.

john916
New User

Apr 20, 2006, 11:04 PM

Post #8 of 9 (1352 views)
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Re: [mel] Toshiba CF30F40 [In reply to]	Can't Post

Thanks Mel, I'll look into that.
On the horizontal..... the center of the sides is curving in vice the whole side. Is that a pin cushion problem? just trying to narrow down where I'll be looking on the schematic.

mel
Veteran

Apr 21, 2006, 9:17 PM

Post #9 of 9 (1348 views)
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Re: [john916] Toshiba CF30F40 [In reply to]	Can't Post

The bowing in indicates a pincushion problem.

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