Featured
Latest
Forums
Electronics - Publi...
Colour Television
1974 PYE CT203/1 - ...
 
Notifications
Clear all

1974 PYE CT203/1 - Hybrid 697 Chassis

 
Page 27 / 27
Colour Television
Last Post by Focus Diode 12 years ago
527 Posts
29 Users
0 Reactions
71 K Views
 Red_to_Black
(@red_to_black)
Posts: 1727
Prominent Member Banned
 

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)
Posts: 4049
Member Deactivated Account
 

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: 3996
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!

Forum 1

 
Posted : 11/12/2013 1:18 pm
 Red_to_Black
(@red_to_black)
Posts: 1727
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: 12227
Vrat Founder Admin
Topic starter
 

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.

 
Posted : 11/12/2013 1:20 pm
 Refugee
(@refugee)
Posts: 4049
Member Deactivated Account
 

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: 731
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
Page 27 / 27
Forum Jump:
  Previous Topic
Next Topic  

You may have missed

xmasroof

A Christmas Tale remembered

crustytv June 19, 2025 7
mitsuban

Mitsubishi PAL Decoder

crustytv June 19, 2025 23
rbm-1

Converge The RBM A823

crustytv June 14, 2025 31
murpban

Murphy Line Output Transformer Replacement

crustytv June 9, 2025 116
ittcvc30-1

1977/78 22″ ITT CD662; CVC30-Series

crustytv June 8, 2025 111