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Hitachi CSP-680 fault

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Jamie
(@jskinner97)
Posts: 1755
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And once again, Fix one set... another goes..

Yesterday the picture went red (Loss of green gun I think)..
Today I powered it up and all the colours look abysmal! With colour off there is no picture.. and overall the screen has no brightness anyway! Now what..

 
Posted : 09/10/2012 10:48 pm
freya
(@freya)
Posts: 1315
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Give it back to Trevor :w00t:

lol

only joking, that aside it could be the tube as they are renown for gun failure

 
Posted : 09/10/2012 11:29 pm
Jamie
(@jskinner97)
Posts: 1755
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Topic starter
 

I hope not! The picture went red the other night as I said, but the picture came back normal so I'm hoping this is a dry joint..it's not been used for a while but was kept in my bedroom so it was hardly cold or damp!

That said, I will give it a prod with the meter tomorrow and check some voltages.

 
Posted : 09/10/2012 11:33 pm
Jamie
(@jskinner97)
Posts: 1755
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By the way, but more help.. Page 80 in r&ts 1972-1973 volume.. Same chassis as Hitachi CFP-470.

 
Posted : 09/10/2012 11:38 pm
AidanLunn
(@aidanlunn)
Posts: 773
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Swap the feed to the red gun with one of the other feeds. This will reveal where the fault is. If it's still the same, it's the CRT. If it isn't, it's the decoder or matrix.

 
Posted : 10/10/2012 1:31 am
Terrykc
(@terrykc)
Posts: 4005
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... With colour off there is no picture ...

Jamie, what this means is that all you are seeing is the chroma information, which is why it disappears when you turn the colour off!

This means that you have lost the luminance signal somewhere. Obviously the decoder is working to give you the chroma information so you can now treat it as a monochrome set for fault finding purposes!

Take a look at the luminance output stage, having made sure the feed to the CRT is intact, of course ...!

When all else fails, read the instructions

 
Posted : 10/10/2012 11:52 am
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