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Old 12th Sep 2020, 8:48 pm   #21
IKC2E51R8
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Default Re: Sharp CA10 green blob on screen.

Not sure if this is relevant to the fault but when this green patch appears of i switch from scart to the antenna and no signal is present the blue mute doesnt function.

Also tried tapping on the screen to bring on the fault and nothing happend. Im going to disconnect the degausse and see if that could be the cause
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Old 12th Sep 2020, 9:58 pm   #22
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Default Re: Sharp CA10 green blob on screen.

Ok so good news is its not the Tube. Its the Degausse Positor. Noticed that when i had it powered off for a bit and powered it back on instead of the usual dull thump of the degausse happening i was getting a faint sizzleing noise. Looks like the positor is gone bad, will replace it to confirm, is there any PTC Thermister that will do for this as I cant find the original part online to buy.

Somehow i missed this last night, may not have had it powered off for long enough when attempting to see if it was a degausse problem.
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Old 13th Sep 2020, 10:53 am   #23
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Default Re: Sharp CA10 green blob on screen.

A picture of the specific degausing thermistor and also a note of all the numbers on it would help in finding a replacement.
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Old 13th Sep 2020, 11:03 am   #24
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Default Re: Sharp CA10 green blob on screen.

P0028CE is printed on it

This pic is the part (found the image on google from an austrialian site)
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Old 13th Sep 2020, 11:34 am   #25
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Default Re: Sharp CA10 green blob on screen.

They don't normally fail the way the dual tablet type do.
I think it is a shadow mask problem.
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Old 13th Sep 2020, 12:05 pm   #26
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Default Re: Sharp CA10 green blob on screen.

The sizzling noise from the Degausse ptc has now stopped and theres no degausse happening at all when the set starts from cold. Im going to replace it anyway once i find a suitable replacment part and see what changes it makes (if any), also noticed a 2.2k 2W resistor near the scan coil plug is completly burned out (colours burned off it and scortch marks at the legs) so will replace that also
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Old 13th Sep 2020, 1:51 pm   #27
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Default Re: Sharp CA10 green blob on screen.

Trust it is not a dry joint on the ptc?
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Old 13th Sep 2020, 2:06 pm   #28
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Default Re: Sharp CA10 green blob on screen.

Those posistors do fail from time to time, however you can usually tell visually as they normally have a big chunk bitten out of them.
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Old 13th Sep 2020, 2:18 pm   #29
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Default Re: Sharp CA10 green blob on screen.

As HamishBoxer says check the soldering of the positor the sizzling noise could simply be a result of arcing of a dry joint underneath, also check all the circuitry of the degaussing circuit for dry joints or loose plug?socket etc
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Old 13th Sep 2020, 2:22 pm   #30
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Default Re: Sharp CA10 green blob on screen.

From the not super close inspection i did i couldnt imemdiatly notice any dry joints, the TV is in my dads house and i have none of my equipment there to check/replace anything, i'll have to bring my teating gear over to check

the positor from what i could see looks ok however there is no deguassing at all so i have suspect its faulty, i'll reflow the pins on it first to see if that makes a difference
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Old 13th Sep 2020, 2:44 pm   #31
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Default Re: Sharp CA10 green blob on screen.

Thanks for the pic, that helped a lot. I have something similar but they are all 'AR' types such as, AR2R2M, AR3R3M, AR3R7N and AR4R7M. The AR4R7M is in a packet that specifies the C1600W model. It might be possible to use a posistor of a different make such as the VA1104 but the specifications will need checking before taking that course of action. Re the AR types as a possible replacement, again it depends the originals specification. The numbers in the AR type are the cold resistance, if I remember correctly.
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Old 13th Sep 2020, 3:44 pm   #32
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Default Re: Sharp CA10 green blob on screen.

Quote:
Originally Posted by G6ONEDave View Post
Thanks for the pic, that helped a lot. I have something similar but they are all 'AR' types such as, AR2R2M, AR3R3M, AR3R7N and AR4R7M. The AR4R7M is in a packet that specifies the C1600W model. It might be possible to use a posistor of a different make such as the VA1104 but the specifications will need checking before taking that course of action. Re the AR types as a possible replacement, again it depends the originals specification. The numbers in the AR type are the cold resistance, if I remember correctly.
Dave
In the Service manual for the CA10 it gives no indication of its specifications, it just has its circuit ref. And the part code no other info
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Old 13th Sep 2020, 3:46 pm   #33
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Default Re: Sharp CA10 green blob on screen.

Quote:
Originally Posted by steve1010uk View Post
As HamishBoxer says check the soldering of the positor the sizzling noise could simply be a result of arcing of a dry joint underneath, also check all the circuitry of the degaussing circuit for dry joints or loose plug?socket etc
I was thinking the same thing when i heard the sizzling that it was a loose connection, the degausse plug seems ok and the pins didnt look cracked or dry but im gonna reflow the whole degausse circuit as you suggest and see if it improves things
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Old 14th Sep 2020, 9:11 pm   #34
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Default Re: Sharp CA10 green blob on screen.

Found the same Positor in an Older Sharp 8P-SR board i had spare, will lift it and fit to the CA10 on Friday and see if it resolves the problem
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Old 18th Sep 2020, 9:28 pm   #35
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Default Re: Sharp CA10 green blob on screen.

I've change the positor and the set now deguasses but the issue persists, ive noticed since this issue began last week the Tube/deflection coils are louder when brighter scenes are being displayed, on darker scenes theres almost no tube/deflection noise. It also makes the occasional 'pop' sound. Ive made a video of it that i'll upload shortly, could it be a deflection issue with the coils or something near the scan coil plug?
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Old 18th Sep 2020, 9:32 pm   #36
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Default Re: Sharp CA10 green blob on screen.

Video of the noise
https://youtu.be/vD_rI3mVxxs
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