Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Model FM-61 Automatic brand fm converter.
#16

I've finally had time to come back to this unit and was able to fix a couple things. One I installed a new output antenna that helped quite a bit with the fading problem. Adding a main antenna helped as well. I had to re string as well as the old one snapped on me.  As for the first problem I'm not sure how to fix that. I did figure out that my stations on the high end of the scale are at the bottom end of the scale but my final high station starts about where it should and but goes to the end of the scale. Now with the rest of the high scale side stations being at the bottom is this still a problem with the FM RF Amp. - FM Conv. tube or an alignment problem?
#17

Update: so I found and replaced the ECC86 tube with one that is brand new in the box testing 950/1000 and there was no change. Same problem, high stations were still at the bottom of the scale with the last station at the top being 103.3.
#18

Ok goto pg 6 of the sam's and locate A8. This adjustment is used to set the high end of the band at 108mc. Making this adjustment will move the stations so pick a local station near 108mc and adjust till you can place the station on the proper location on the dial.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#19

So I'm finally getting back to this one after some distractions and I have made some improvements but not 100% there yet. So I moved the A8 a little and it didn't do anything, so I set it back and found that the A9 moved the scale up and down. So I now have my scale set in the right spot and in the process some of my stations have come back at the top as well. My final local station is now at 105.5, almost getting the next one at 106.3. A quarter turn either direction does nothing, do I keep going until it changes?
#20

A8 isn't going to move the stations, it effects the sensitivity. A9 will move the stations. Since you don't have the proper generator to align it use A9 to move the highest in frequency fm station in your area to it's proper place on the dial. I suppose you could run out of adjustment. Don't adjust the 10.7 IF transformers.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#21

I think I may have it, I had to turn the screw about 1/8 more and they're all on, I just need to slide my indicator about 3/8 to the left and everything should line up. I probably still need to change the electrolytic capacitors in this for it to be completely reliable. I couldn't find the exact value for this unit, it calls for 400mfd @ 15 volts, best I could get was 470mfd at 25 volts, will that be okay?
#22

a little over on thee mfd and volts is NOT a Bad thing,,,,,NEVER under,,,,CHEERS
#23

(01-02-2017, 02:39 PM)flatheadjr Wrote:  I think I may have it, I had to turn the screw about 1/8 more and they're all on, I just need to slide my indicator about 3/8 to the left and everything should line up. I probably still need to change the electrolytic capacitors in this for it to be completely reliable. I couldn't find the exact value for this unit, it calls for 400mfd @ 15 volts, best I could get was 470mfd at 25 volts, will that be okay?

Yup you fine.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#24

I would not worry too much about changing the electrolytic. 

That cap is just a filter for the +12V to eliminate alternator noise. It otherwise does not affect the operation of the tuner and its a low voltage sealed metal can type which is quite reliable.
#25

Any way to check that capacitor to make sure it's in good shape?
#26

If it were mine I would connect it up in my car and see how it operates. If you here whine from the alternator on the radio when you accelerate the engine then the cap might need replacement. If you hear the alternator noise, you can jump the replacement caps across the existing terminals and see if it makes any difference

Otherwise you could disconnect all the wires and components from the cap terminals and check with a capacitance and ESR meter, but I would not bother as it would be just about as much work as installing new caps. Unless you remove and restuff the existing capacitor can with new electrolytics, you will have to install terminal strips to mount the new caps and the existing components connected to them.

That electrolytic has only 12 VDC across it and the chances for failure are minimal. Again, the only purpose for the cap is to filter the alternator noise so if you don't hear it then it is fine as is.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

[-]
Who's Online
There are currently no members online.

>