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1974 PYE CT203/1 - Hybrid 697 Chassis

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Red_to_Black
(@red_to_black)
Posts: 1748
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Excellent, well done Chris. :aap

See the previous laws :aak
posting.php?mode=reply&f=5&t=3167#pr73948

 
Posted : 11/12/2013 12:59 pm
Refugee
(@refugee)
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Would that be the one that looks to me like it is marked C255 on the circuit that was posted a page back up the thread?
That would have put in negative feedback in via the oscillator and reduced the height.
I was thinking of C256 although that may only have taken the top of the scan off.

 
Posted : 11/12/2013 1:09 pm
Terrykc
(@terrykc)
Posts: 4005
Member Rest in Peace
 

It may take me longer than some but I get there in the end. Finally tracked the culprit down to C455 470uF @40V, it was leaking badly ...]

Well I'll be damned ...!

It had occurred to me that, when I put the previous schematic together that I'd skimped on the earthy end of the scan coil return (the Frame Shift control shown is relatively high impedance) and had just finished putting this together when you posted your news!

When all else fails, read the instructions

 
Posted : 11/12/2013 1:18 pm
Red_to_Black
(@red_to_black)
Posts: 1748
Prominent Member Banned
 

Would that be the one that looks to me like it is marked C255 on the circuit that was posted a page back up the thread?
That would have put in negative feedback in via the oscillator and reduced the height.
I was thinking of C256 although that may only have taken the top of the scan off.

C455 is associated with the frame shift control and the transductor leading to the convergence circuits, by the circuit diagram it looks to be on a different board to the frame circuitry, Terry's stitched together diagram shows it.

 
Posted : 11/12/2013 1:19 pm
crustytv
(@crustytv)
Posts: 11903
Vrat Founder Admin
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Would that be the one that looks to me like it is marked C255 on the circuit that was posted a page back up the thread?

Not sure what you're looking at but C455 is connected to the Frame Shift.

Edit:
Cross posted with R2B

by the circuit diagram it looks to be on a different board to the frame circuitry

Hence me spending a couple of days thinking the frame PCB was the be all and end all of the circuit and confused when all the board components checked ok. A good lesson learned.

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Posted : 11/12/2013 1:20 pm
Refugee
(@refugee)
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What a sneaky capacitor that was in the convergence panel lurking by a diode wired AC128.
There was me guessing that it was C255 :ccg

 
Posted : 11/12/2013 1:23 pm
Focus Diode
(@focus)
Posts: 729
Honorable Member Registered
 

Excellent! Well done Chris.
After all the hard work you've put into the set I hope it behaves itself for a few months at least.
Cheers,
Brian

 
Posted : 11/12/2013 3:10 pm
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