Discussion in 'Fisher' started by rufleruf, Mar 16, 2017.
Dave - here are backed up pictures - you can just see the disconnected relay wire.
It's hard to tell your absolute connections on the rear of the switch due to the depth provided in the pic, but ultimately, they should connect this way:
1. The 560K resistor goes to the "top" terminal of the control (terminal closest to the bottom plate). That is the only connection to that terminal.
2. The 470K resistor goes to the wiper terminal of the control. That is the only connection to that terminal.
3. The bare wire from the T-strip ground terminal comes over to one switch terminal, from there over to the "bottom" terminal of the control (closest to the chassis floor), and from there to the lose lead from the relay.
4. The other switch terminal associated with the grounded switch terminal connects to the black lead going over to the nearby 15 Ohm resistor on the lamp array (the inclusion of the 15 Ohm resistor is a modification by someone, not Fisher).
5. The other two related switch terminals have the 330K on one terminal, and the black lead going over to the muting oscillator coil on the other.
I hope that helps!
Dave - thanks for the instructions. I got it all hooked up. Passed DBT so I plugged it into the KX100 I've been cleaning up. It powers up and plays, but mono plays through one channel and if I switch it stereo the other. I think mono is left, but I haven't verified all connections are correct. AFC light comes on, muting does not seem to work. I plan on testing all tubes and cleaning pots and sockets before I go any further.
I suppose the .1uf brown caps in these are suspect, and the electrolytics are assumed to be out of spec if not totally dead?
Certainly replace any small electrolytic caps, as well as the power supply cap, and change the rectifier to silicon using a 100 Ohm dropping resistor as I've described before. The film caps can be replaced, but are at the low end of your to do list.
Clean the relay contacts, and that may resolve your sound issue from both channels.
Make sure that your switch leads on the muting control are correct -- that you don't have the leads crossed between the two separate switches. That's why I gave the detailed instructions for their connections. Use your Ohmmeter to verify which two terminals go together for the two separate switches within the muting switch.
I've got a Mouser order coming for jewels and electrolytics. Two of the tubes were bad, and the pots all need cleaning (of course I forgot to order deoxit), so I have some house keeping to do before I move forward on it. Need to look up "stereo relay contact cleaning" on google. And then there is the likelihood of MPX adjustment being needed... and my Hickok 752 is currently out of commission...
I may dig into the FM100B while this one is in holding pattern. Right now my pile of restored ones is quite a bit smaller than my pile of projects.
Matt; Cut some paper strips sized so they will fit in between the contacts. Drizzle some Deoxit on them, then insert to one end and pull thru to the other end. Discard that paper and keep doing the same about 5-10 times on the contacts (held closed) until the paper comes out clean. 1 pass on each paper. Don't go back and forth on the paper.
Okay - a little progress:
Replaced all the electrolytics except the 1uf 350V - I have some, just ran out of time.
Rounded up another 6DJ8 and got some nice 6BL8 Bugle Boy's from AKer Byoungman so all tubes are good now.
I verified the DPST switch is hooked up correctly, but I still am not getting the muting light. Left channel is nice and loud and tunes in well, the right side is barely audible. I worked my way from the RCA jack to the relay and I am getting strong left and right signals in, but only a strong left out. Oh, not getting the stereo beacon light either. Relay definitely wants a cleaning.
Still need to replace Mylar caps and clean controls.
Looking forward to having a working Fisher tube stereo tuner!
Check your bulb? Making contact?
I did verify the bulb and most of the wire path. If I manually toggle the relay the muting light comes on - need to check one of the lower solder joints that's hard to see - might just be making intermittent contact.
After my post above I spent 30 minutes and replaced all but a few of the Mylar caps - ran out of .1's -need to order more. All problems seem to be relay based now, but I still haven't cleaned the pots and switches. Going to Frys Electronics today at lunch to get some cleaner. No point in troubleshooting anything else until they're all clean.
I'm lost here.
The MUTING lamp is controlled by 1/2 half of the DPST switch on the back of the Muting Control (the one you just replaced), and only by that switch. Nothing else controls that lamp -- no other switch, no relay, nothing. When the Muting control is turned on, the muting lamp glows. When the Muting control is turned off, the lamp is extinguished. It's that simple. Which is to say, the lamp does not go on and off automatically as the unit might go into and out of muting action.
Now, the AFC lamp is controlled by contacts on both the AFC switch, and AFC/Microtune relay. Therefore, if the AFC lamp contacts on either the AFC switch, or the AFC/Microtune relay are compromised, the lamp will not light under any condition.
The bottom line is that unless something is either mis-wired or cross-wired in your unit, it is normally not possible for either of the two relays it employs to active the Muting Lamp.
Could you please clarify these facts in your unit?
Yup, as Dave notes: turn the switch, lamp lights. Turn it off, lamp goes off. Nothing else should be involved.
What I found flaky in the bulb array as it is set up is the contact in the back (where you have that 15 ohm carbon resistor connected.) In both my 200b and in my x-202-b I had to bend it slightly because it was loose and it wasn't making solid contact. If it's not a mis-wire, see if that contact is causing your problem. Is it shorting to the next housing?
Dave - I will look at the wiring tonight again, I thought I cleaned up all the wiring after the last guy pulled the switch and whatever else went on, I might have missed some snipped wires. I just got some contact cleaner and DeOxit fader lube, so it's game on there. Hopefully it is just a bad connection to the bulb.
Should I remove the 15 ohm resistors at the lamp backs?
I'll post some updated pictures and map out what causes what to work. I guess it woudl help if I read the owners manual so I knew what it was supposed to be doing.
Comparing the pic of your switch connections to my pic, they look to be different. From what I can make out, if you switched the 330k with the long black wire it'll be wired the same as mine.
You guys are right - I wired it wrong. I'll get it rewired later tonight.
Anyone know where to get the dial lights for this? They're a little smaller than the usual 500C etc ones.
If they are the 1-1/4" Fuse type,www. wjoe.com has them in incandescent or LED ready to go. Or contact www.dgwojo.com He's the lighting guru here on AK.
I'll measure. They're slightly shorter than all the spares I have, and need to be narrow.
All done - everything seems to be working now. I have 4 .1uf caps to replace when I get an order in next week, but that's just preventative.
I found some 7W LED dial lamps leftover from some long forgotten project to install for the dial glass. Even found a new #47 lamp.
Face plate and chassis cleaned up really nice. I'm happy with it. Very quiet tuner compared to the Stromberg it is replacing!
Matt -- As a small detail -- more in the just so you know department -- the green and amber jewels on your tuner are reversed. The center (stereo beacon) lamp is where the green jewel should be located, with the amber jewel lit when the muting function is activated.
Thanks! Probably hard to believe my first instinct was to part it out - missing the knobs and that muting switch and all.
I'll swap them when I do the caps. If anyone needs a jewel I'm happy to send them one - I bought a bunch!
I hope your ready for some dumb FM100B questions. Might be doing that one next.
It's a sweet little tuner!
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