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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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12th Sep 2020, 8:48 pm | #21 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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12th Sep 2020, 9:58 pm | #22 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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13th Sep 2020, 10:53 am | #23 |
Octode
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,689
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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.
Dave |
13th Sep 2020, 11:03 am | #24 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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13th Sep 2020, 11:34 am | #25 |
Nonode
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,473
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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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13th Sep 2020, 12:05 pm | #26 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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13th Sep 2020, 1:51 pm | #27 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
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Re: Sharp CA10 green blob on screen.
Trust it is not a dry joint on the ptc?
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13th Sep 2020, 2:06 pm | #28 |
Nonode
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,473
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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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13th Sep 2020, 2:18 pm | #29 |
Pentode
Join Date: Nov 2006
Location: East Yorkshire, UK.
Posts: 130
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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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13th Sep 2020, 2:22 pm | #30 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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13th Sep 2020, 2:44 pm | #31 |
Octode
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,689
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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.
Dave |
13th Sep 2020, 3:44 pm | #32 | |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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Re: Sharp CA10 green blob on screen.
Quote:
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13th Sep 2020, 3:46 pm | #33 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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Re: Sharp CA10 green blob on screen.
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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14th Sep 2020, 9:11 pm | #34 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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18th Sep 2020, 9:28 pm | #35 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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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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18th Sep 2020, 9:32 pm | #36 |
Hexode
Join Date: Aug 2018
Location: Dublin, Republic of Ireland.
Posts: 492
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Re: Sharp CA10 green blob on screen.
Video of the noise
https://youtu.be/vD_rI3mVxxs
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