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Old 28th Jan 2019, 6:14 pm   #158
19Seventy7
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Join Date: Jun 2018
Location: Essex, UK.
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Hi

I thought I would link this thread to the now closed "What Diode?" thread.

"What diode?"
https://www.vintage-radio.net/forum/...d.php?t=153497

Quote:
Right, so the diode isn't crozzled? The resistor is? Do you know it's value, I think not if it's charred. Lawrence is your guy for that. As I said earlier, the diode is probably OK. Some confusion arose and it was assumed it was the RGB diode that had failed but that would result in an over bright raster. I think we all have a better idea as to which components have failed, but be aware when you restore your raster you will still have the shading. When you ascertain the value of the said resistor and replace it you "may" get your picture back. Have you no idea why it failed, because of where it is in the set it's unlikely to be a safety resistor, but not being terribly familiar with that model who knows.
The diode hasn't burned, the resistor had; which I got wrong in the linked thread as I mixed the two up and said the diode had burnt.

The resistor is a 1.8kohm metal oxide resistor. I have ordered a replacement, valued at 2watts which I was told should be okay.

How do I fix the shading? I was told replacing two capacitors would sort this, which I have changed, and that's when I had no picture.

Thanks

Ah right so it is the A1/screen diode, the confusion earlier was down to me, as I was under the impression it was the RGB 200v supply that was in trouble, my mistake.

Okay, do you know which A1 it would be from the list (See attached) as there are multiple.

Thanks

Thank you all for your help! It's really appreciated.
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