Maker Pro
Maker Pro

Hitachi KH-1190E radio stopped working

73's de Edd

Aug 21, 2015
3,432
Joined
Aug 21, 2015
Messages
3,432
Sir Martfoxy . . . . .

A 1N60 GERMANIUM junction is exactly what is being needed . . . and the junctin voltage tested is being proper.

As for your clipped C42 fixed ceramic or silver mica capacitor, seems like it met the guillotine of the final test and ALIGNMENT person.

It is in parallel with the C43 variable capacitor to get an adjustable value of from 12 - 32 pf to properly resonate with the cojoined primary winding of the L5 antenna coil for the LW radio band sector.
They must have found there being TOO much capacitance to properly align to spec and to achieve OPTIMUM sensitivity / tracking, so they clipped it out to then have the reduced end result of only a few pf on up to the full 20 pf limit of the sole use of C43.

Now . . . . . just for testing, do you have enough random resistors, so that that you might multi series- parallel-tandem- quasi - shunt together enough selected values . . . . to end up with that opened ~ 150 ohm unit being needed ? . . . . Or was a 150 also being included in your diode order ?
THAT IS . . . . . unless you STILL have that intolerable 7 ohm resistance reading across the two solder pads of the once vacated D5 zener diode ? ? ?


Boom . . chuck . . a . . . lug . . . . Here it is ! . . . . . le C42

upload_2021-1-22_8-38-22.png



Thaaaaaaasit . . . . . . .

73's de Edd . . . . .


.
 
Last edited:

Martfoxy

Apr 25, 2013
54
Joined
Apr 25, 2013
Messages
54
I have tested the zenor diode and get 4.4v. I managed to get another 150Ohm resistor (159Ohm). However its still not working. I measure to the zenor diode and get about 5.6v.

I found out if the power switch is off then I get 2Ohm across C84 1000uF capacitors , but when its on I get about 56 Ohms. I get 0.056 v across that capacitor. The other 1000uf C24 I get 5.5v across it.

I plugged a DIN lead into the radio from my stereo headphone socket and to get a slight sound out of it, I have to turn the stereo volume right up.

I have just noticed some damage on the pcb I am not sure when it happened. Photo attached.

Thank you
 

Attachments

  • damage.jpg
    damage.jpg
    97.4 KB · Views: 3
Last edited:

Martfoxy

Apr 25, 2013
54
Joined
Apr 25, 2013
Messages
54
I have put some bridging wires in to bypass the damage. It was for the ferrite coil. The radio still produces no sound.
 

Martfoxy

Apr 25, 2013
54
Joined
Apr 25, 2013
Messages
54
I have found a 100uF capacitor that is reading 30uF on my meter. I have ordered a replacement to see what happens when replace it. Its C67 between the ICs.
 

Martfoxy

Apr 25, 2013
54
Joined
Apr 25, 2013
Messages
54
I have just replaced the suspect 100uF capacitor with one I received (much smaller physical size) but the radio remains more or less silent.
 
Top