Hitchai radio KH-1190e not working

[Martfoxy]

I have a problem with a Hitachi KH-1190e that is only producing a soft white noise. However I did notice when I was testing the voltages if I bridge two tracks it starts working ok. I have attached a diagram to show which tracks I bridged.

I tested Q5 as near and got: (without bridging the tracks above)
B 1.098v spec says 1v
C 3.82v spec says 3.3v
E 0.80v spec says 0.35v

(I did have a previous fault which is fixed which turned out to be a shorted coil - I believe this is ok still as not getting the resistance value I was getting before).

I have attached the pcb track diagram with blue arrows showing the two tracks I bridged.


Thank you

 

[Martfoxy]

Also attached the circuit diagram.

 

[73's de Edd]

You are shorting across R16 which is being . . . . Q5 AM and FM I.F. amplifiers . . .emitter resistor . . . with a value of 330 ohms, any chance at it tests high or is open.
F.I.O. . . .The follow up circuit diagram needs to be the original . . .as a PDF . . . . since that image that you submitted is so small as to be useless.


I did have a previous fault which is fixed which turned out to be a shorted coil.
Expound a bit more on that " shorted coil " aspect, unless it was a solder bridge.

 

[Martfoxy]

R16 measures 335 ohms.
Sorry about the circuit diagram I didn't get a pdf it was a paper copy of the manual. I will try again.

 

[Martfoxy]

About the shorted coil - it was T5 - the pins on both sides were connecting together. I replaced this and the short was gone.
We found this by putting batteries across the two shorted tracks and it got warm.

 

[Martfoxy]

I think this coil has now shorted - I noticed the short had come back as before. So I took the coil off and it measure 1.8ohm from the 2 pin side to the three pin side.

 

[Martfoxy]

Maybe where the two wires are twisted together.

 

[Technomaniac]

Martfoxy, IF you persist with your current methods of servicing you will write off everything you possess. Connecting a battery across two points to see if they are shorted may have been OK in 1910 electronics but is a sure way to keep introducing more and more faults as you go. You can't even put your FINGERS across the PC tracks with modern electronics without destroying something.