Hitachi C14C-5090 illusive schematic attached!

andrew96

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Hi
here is the schematic for the C14C-5090

I finally had to buy a Crazy Climber manual just to get this one page schematic!!

can someone download it then compress it and post it back here? i have been unable to get it under the 40k pdf attachment limit as it becomes unreadable! so if someone could post it back that would be great!!

http://www.andrewfinn.co.uk/C14C-5090.pdf

this is the chassis pic http://www.therealbobroberts.net/unknown1.html

do i need to start another thread for this?? Have found the B+ line is marked on the board as 112V, is on the schematic as 112V but on my chassis its 102V. all resistors/caps/transistors checked/changed and its still the same. only difference i can find is R912 on the diagram on the voltage reference chain is 330R, but it 390R orignal on the PCB. i changed it to 330R and B+ went up to 105.8 volts! close but not close enough!

so does anyone have this chassis just to quickly measure the B+ as i am not convinced 112V is correct, seems 102v is more on the mark but because of this the line scan is lacking width, so is 112v right after all??

someone???

thanks
Andrew
 
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I have finally sorted this out now, i managed to get a HM9102 module...... still the same! 102.7v

so after studying the circuit more and found the HM9102 was nothing more than a resistor voltage divider and doing some calculations I decided to lower R912 from 390r to 330r thus lowering the voltage on the base of Q902 causing it to conduct less. this had the desired effect and the B+ rose to 105v !! changing it to 270r and it rose to 108v

The final resistor value turned out to be 195r to get 112v and the width just filled the screen just as expected! so just added another 390r across the 390r R912 already in circuit. the B+ measured 111.9v just right! think i will leave it as that!

I did think of putting a variable pot in place of R912 but it would be very difficult to get at as larger higher powered resistors are just above it! the resistor idea is better i think as there is no pot to go intermittant later in its life

anyway its fixed good enough for me!

Andrew
 
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