Pentranic chassis screen jumps

[Retroman839]

what i would do,
install diode and cap, leave everything else as is for time being
test voltage at cathode of d506, if all is good install resistor r318 and link to pad of cathode - i think there is a through hole marked B you can use for the wire

Yeh i s the hole marker B
Ok i will do thst

 

[Retroman839]

Other than that im curious whete my power supply for vcc of vertical oscilator currently is being drawn?
I hve asked Rick s well
Hence the effect im getting seems the issue rhat related to flyback causing over voltage to thr vcc

 

[Retroman839]

without this in front of me its so difficult to see the multiple mods you can do, i think you will also need to link the anode side of the diode to pin 3 of the supply transformer. you can see through hole for wire jumps all over this chassis

Yeh and also i need to disable current supply also right ?
But thats done just by lifting resistor leg out r318

 

[Retroman839]

I will pop in the 680 ohm at r318
Pop Cap in at c333
And diode
As should be and see if hole with B takes the jumper wire solderd in to link it to cathode of the diode then ?

 

[Retroman839]

50v 1000uf ok ?

 

[gunblade]

yes
how does the anode connect to the transformer?

 

[Retroman839]

 

[Retroman839]

yes
how does the anode connect to the transformer?

At a guess through a large cement resister ?
This anode and this trans ?

 

[Retroman839]

 

[gunblade]

you are going to blow this up

 

[Retroman839]

yes
how does the anode connect to the transformer?

you are going to blow this up

Why ?

 

[Retroman839]

Anode to rectifier diode inside the flyback

 

[Retroman839]

i dont want to blow it up?

 

[gunblade]

coz you are pointing at the horizontal drive transistor
which transformer do you think is the supply transformer?

 

[Retroman839]

Anode is connected to transformer with the EHT lead externaly

 

[Retroman839]

coz you are pointing at the horizontal drive transistor
which transformer do you think is the supply transformer?

TDA4605
Then rectified to dc

 

[Retroman839]

Please dont let me blow it up
🙏
I have been wanting to fix this for 4+ year

 

[gunblade]

T501 is the supply transformer, pin 3 supplies the vertical ic in the original schem you linked to via d506 and c333
the large ceramic resistor you were pointing to looks to be R501 which is on the b+

 

[Retroman839]

T501 is the supply transformer, pin 3 supplies the vertical ic in the original schem you linked to via d506 and c333
the large ceramic resistor you were pointing to looks to be R501 which is on the b+

Got it

https://arcarc.xmission.com/PDF_Monitors/Pentranic%20CH-288%20Switchable.pdf

 

[gunblade]

so if you look at the location of d506 it looks like sweet fa goes to the anode, is that correct?