Sony TV 9-304U Repair missing Service Manual

[mark-ch]

I recently came accross that beautiful Sony TV 9-304UE in absolutely perfect shape with cover and even the user manual. Finally an opportunity, to watch the old tv test cards the way it should be - particularly the very old Swiss testcards I reconstructed quite some time ago.

I am somewhat skilled in repairing old electronic stuff, but not THAT skilled...
After visual examination of the internals, I switched the TV on. Sond and horizontal deflection is ok so far, just the vertical deflection is shrunk to about 1 cm height. (picture visible) I know a little about that defect. I managed to get a fairly readable circuit diagram, but NO service manual.

The only visible defect is that interesting resistor, obviously blown, 630 Ohms I suppose, the ONLY one with silver cap (10%??) I also never encountered these vertical resistors. Furthermore interesting: Its soldering points on the back of the PCB are marked with a blue felt-tip. I also cannot see where it belongs to in the circuit. Appears to be the deflection...

Questions:
- Does anyone have or know about a service manual of this TV?
- That blown resistor, I guess, it is just a normal resistor. Is there anything special about that vertical form?

Thanks for any help.

...actually not switching it on anymore before first repair attempt - no example of the actual picture size. Hor = ok vert = about 1 cm height.

[Electronic M]

Sets of this vintage the capacitors (especially electrolytics) usually fail from age. They mounted all different types of component vertically to save board space...As long as you have identified it properly there is nothing electrically special about it to worry about.

[Mr Hoover]

Hi,you might want to look at these videos on YouTube,a guy in New Zealand restoring the same model.I think there are four videos in total.
https://youtu.be/VFJ6dPZ0itQ
I have quite a few old Sony's,not that
one, you'll have to change a lot of electrolytic capacitors.
Radio Museum will have the circuit.

Good luck!
Hugh

[Mr Hoover]

Radio Museum link.
https://www.radiomuseum.org/r/sony_t...tv_9304_u.html

[mark-ch]

Thanks for the replies. Just saw all the parts that New Zealand guy replaced - there will be some work to do. He obviously knows, what he does. I will go trough it again.

Just found an original service manual for sale on ebay. I hope, it contains a circuit layout - the Radio Museums scan is readable - mostly...
I am quite cautious, if it comes to high voltage.

Lets call it a project with some potential

[Electronic M]

Unless you have a heart condition or grab a the HV line with the set running there is little danger... I've been bit by 25kv before... It's like a mean jolt of static electricity, you'll cuss and your heart may race for a bit but you'll be fine in minutes.

I've lost count of the HV bites I've gotten... what you really want to be careful of is high current sources like the wall outlet and B+ in valve/tube based sets. Flyback based sets are only designed to produce around 1mA of HV for current hungry color sets. Tube sets produce hundreds of mA for B+.