Well my whole writing is just magicaly dissapeared after I accidentally pressed close button Anyway I got this AM radio and the only function that doesnt work is the indication meter. Battery percentage works so the meter itself is working, there must be a issue on the circuit that controls the indication meter. There is a video about this particular radio: You can see how meter works to show radio signal strength, I got nothing. I saw little movement when I catch a loud noise in long wave mode but thats it. Is this worth fixing.
Nice radio! This is pretty common with the older radios that have been sitting for a long time. With mine I work the switch that changes the mode from battery to level until I get movement. If you have a good contact cleaner like DeOxit, that will help clean those metal surfaces. What's odd is they always seem to work when checking on the battery but never with audio, maybe someone else knows why?
I cleaned the buttons as much as I can with a ear stick. I can't remove the mainboard even I remove all of the screws and I cant reach those swithes because of that. I tried to switch button several times but it didnt help, It is really weird.
I poured sone deoxidizer in to the button with a syringe, it works even smoother now but still the same issue. There is no service manual explaining how to open this they just show the circuit diagram.
Here's the service manual, hope this helps, you'll have to sign up on the website to download it. Good Luck, I still would work on that knob, it looks like it goes in and out and rotates, there might be some holes on the side to squirt the cleaner in but you'll have to open it up to get access. I love the little orange accent on these older Hitachis. https://www.radiomuseum.org/r/hitachi_kh_1170e.html
Unfortunately I dont understand circuit diagrams, at least not enough to find the problems source. But I did clean the buttons and this is most likely not a button problem. There is a photo of the radios inside, maybe you will see something I cant.
Hello.... The electrical circuit that I managed to find was divided into two pages but I managed to merge them ... as you see from the colored circuit all the ovals numbered 1 up to 8 are part of a single switch ... the area that interests and the number 3 ( red) that controls a transistor ( q 203 ) .... most likely the section of the switch does not work well ... or oxided ... start from the transistor and follow the copper tracks of the circuit ... the base of the transistor and connected directly to the switch...From your photo you can see the transistor
Thanks man, The only problem is. those buttons are all in other side of the pcb and I can't remove the board even I remove all of the screws. Something from left side holds it and its not potansiometer plastics. I will try to remove it again tho.
You have to remove the round knobs ... underneath there will be a holding screw like the old potentiometers
Ahh, there are bolts down there and I will need a special tool to remove them. Although I found the switches you mentioned. There are in that metal box next to the transistor. I cleaned them nicely with deoxidizer but still no response from the indicator.
exactly the switch and that ... the flux you have to get it inside .... or try to resolder the points of the switch
Its been a year. I was bored and I remembered about the radio. When I was trying to fix it I didn't had alcohol to clean the contacts, so I stupidly used WD40 and other lubricants which didn't work as expected. Today I cleaned all the WD40 remains with isopropyl alcohol. I was not expecting anything but when I turn on the radio signal meter moved to the middle, it was finally responsive. I cleaned the switch multiple times with alcohol again. It is not stable or accurate but it works now. Just wanted to say that.
Well just when I was happy it turned into its old state. What I believe now is, it needs resoldering as @Silver965 said. Because jack socket one channel got disconnected while I was trying to use my headphones and now it only works when I push it with an angle. Probably same happened with the main switch solders and alcohol some how connected the lose solder points together and when it was totally gone the signal meter was gone too. The responsiveness of the meter slowly disappeared into its old state while it was drying. Since the first pot on top also doesn't work I am really suspecting solder degradation problem. This thing was also used a lot and it was really dirty even after cleaning it more then 5 times so I really want to clean its parts separately. The problem is I can not remove the circuit board because potentiometer screws are holding it in place
