[TechAssist] RCA F27351WN CTC177BE chroma in luma, clipping
- From: "Leonard G. Caillouet" <lcaillo@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 22 Dec 2003 15:21:59 -0500
This set work ok except for a little distortion in very intense colors. All
test patterns look good except a luma/chroma sweep shows a heavy crossweave
pattern in the 2.0 - 4.0 Mhz range and horizontal colored bands in the lower
frequencies, like what you get on a luma sweep when a color killer is not
working.
The color killer is working fine. It looks like all the filtering is done
in the chip so I replaced U1001 (LA7610) and no change. Replace the color
crystal and related parts and not a change. Changed the EEPROM just to see
if it might be bad, no effect. S-video is clean, composite video has the
problem. It seems to me that it has to be something peripheral to U1001
that affects the filter characteristics, but haven't found it yet. Any
ideas?
I only have part of the schematic for this one, so if someone could scan and
email or copy and fax the relevant area I'd appreciate it.
Thanks,
Leonard G. Caillouet
Electronics World
Gainesville, FL
352-332-5608
352-332-5668 (fax)
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