FM-200-B Refresh

Not -- If your Muting lamp does not turn off, either there is a short in the lamp wiring (grounding out the lamp connection normally grounded when the switch is turned on), or the switch in your unit is flaky as well.

The middle lamp is the Stereo Beacon, which should come on whenever the MPX decoder triggers the Stereo Beacon relay into stereo mode. If the light is not coming on, then either:

1. The lamp is bad.

2. The relay contacts for the Stereo Beacon lamp are dirty, or

3. The MPX decoder is not triggering the Stereo Beacon relay.

If you know you are getting good stereo sound (and you can hear the relay click as you move on and off of a stereo station), then likely the lamp if bad, or the relay contacts are simply dirty. One quick easy test is that the lamp should come on momentarily while the tubes are heating up when the unit is first turned on, and then go out. If this is not happening, then the lamp, or the relay contacts are suspect. Good luck with it!

If I may ask a favor, could you put up a shot of the spring contact behind the tuning wheel that connects to the Microtune circuit in your unit when you get a chance? Specifically, I'm trying to determine if that contact should always be in contact with the end of the tuning wheel shaft, or if there should be a gap. I'm of the opinion that there should not be a gap. The tuner I have looks like it's been monkeyed with in this regard, but I'd like to find out for sure how it's supposed to be. I tried Punker X, but he said he hadn't worked on one in a long time, and couldn't remember. Any help would be appreciated!

Dave
 
No problem Dave. I won't be able to get to it until this weekend but I will.

As far as my lights are concerned. I know the lamps are good cuz the most I was willing to do without de-casing it was pull the faceplate and swap the bulbs: all good. The relay clicks but given the fact that this thing sat in a box for who knows how many years, it may very well be that there is a contact issue. I'll dig into it more when I open it up this weekend. Thanks.
 
Dave, in the 1st pic of the dial lamp, looks like some extra padding under the screw that holds glass in place, someone also really messed up the head on that screw...(not you), probably the guy up north. Glad these lamps will be easy to change out now should the need arise. Would not mind seeing how LED's look for the fun of it, I know you use em..:)
 
dcgillespie said:
.....
I've used and like the LEDs as well, which tend to give a more modern look. There are also folks who like the warmer look of the original incandescent bulbs, too. Both look very good to me, with each having their own individual preference.

Dave
Click to expand...

The LED strips are available in 2 colors of warm white in addition to bright white.

6000K color temperature

http://www.amazon.com/dp/B002QQ1YOM/ref=pe_113430_20118850_pd_re_dt_w5

2700K color temperature .....

http://www.amazon.com/Flexible-LED-...07EW/ref=sr_1_6?ie=UTF8&qid=1314593933&sr=8-6

3100K color temperature .....

http://www.amazon.com/Flexible-LED-...ref=sr_1_5?s=hi&ie=UTF8&qid=1322077358&sr=1-5
 
Whichever lamps you decide on, at least they'll be easy to change out now! And yep -- the dial glass hasn't been touched, but the extra stripping should be easy to remove.

Dave
 
Dave; All of the receivers/tuners I've seen with the leaf spring on the end of the tuner wheel is actually touching the end of the spindle. I always thought they were there to tamp the longitudintal slack in the bearings, like a thrust bearing.

Larry
 
Larry -- On particularly the 200B, the "leaf spring" is really an isolated (from ground) contact that has a wire connecting it to the Microtune circuit. The flywheel itself then is also isolated from ground by the use of non-metalic bushings.

The question posed about whether the leaf spring should be in contact with the flywheel all the time is based on trying to determine whether you are supposed to lightly push in on the tuning knob (against the slack) to deactivate the Microtune circuit (as would be the case if a small gap in the contacts exists), or simply touch the tuning knob, as would be the case if the contacts were touching all the time. Since this is the first 200B I've ever seen up close and personal, I'm simply trying to establish what the intent was of the original design and build.

I am contending it is likely the latter (simply touching the tuning knob), as I believe that is the way Fisher would have wanted the feature to operate. Also, the owner's manual says nothing about having to push in the the tuning knob to deactivate the Microtune circuit.

The contact mechanism on this particular tuner however appears to have been monkeyed with somewhere along the way, so that now you must press in on the tuning knob to deactivate the Microtune circuit. Note the pics provided:

1. In the first pic, the gap between the end of the flywheel shaft and the leaf spring contact is obvious. Also note however, that the top of the L-bracket no longer represents a straight edge -- nor does the L-bracket itself effectively represent a 90 degree bend anymore, despite the stamped indentations at the actual bend of the bracket to reinforce a 90 degree form. As a result, the rear of the L-bracket is lifted up off the chassis surface. Note too that the bakelite insulator for the leaf spring contact no longer sits flat against the rear of the L-bracket either. Finally, note the deformity in the leaf spring contact itself, where it lifts away from the top of the bakelite insulated mounting strip.

It appears that somewhere along the way, a gap formed in the contacts, and somebody's first "fix" was to retention the leaf spring, resulting in it's deformity. When that didn't work, then they simply bent in the L-bracket to eliminate the gap. Or, it could have been the other way around. But either way, that only made matters worse, as then:

2. In pic two, the deformity of the leaf spring contact can be seen more clearly. It appears that one, the other, or both of the fixes previously attempted then popped the top insulated rivet mounting the leaf spring and its bakelite insulating block to the rear of the L-bracket. This was then attempted to be repaired by soldering the rivet to the leaf spring contact as show in this pic.

The net result of all this is that currently, a significant amount of both lateral and front to rear play exists in the leaf spring contact mounting, requiring the tuning knob to be pushed in (taking up the slack) so that the rear of the flywheel shaft will actually touch the leaf spring contact, and then disengage the Microtune circuit (which itself works just fine).

All of this may be a moot point, as the Microtune feature may not be used that much or at all on this tuner in the first place. But, it is an element of the unit's proper operation, and with a request of "make it like it was yours", you look at everything in detail, which I always try to do anyway with any piece of equipment.

And so the original question is posed. In looking at what form a really proper repair might look like, is the leaf spring supposed to make continuous contact with the rear of the flywheel? If a repair is made, getting the details right about it is everything!

Dave
 

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After sitting here looking at Picture #2, looks as though it should make continuous contact, looks like the L shaped bracket is bent ....any one got a pic we could compare with? Thanks Al
 
Agree. PIONEER did this in 1977-78 with the SX-1980 just by touching the knob, it would unlock the quartz lock and and you could tune within +/-8kHz and the light's would light up, then let go and the channel would lock up. Liink to the SX-1980 Brochure for clarification....... http://www.kallhovde.com/pioneer/sx-1980-b.pdf
 
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dcgillespie said:
The question posed about whether the leaf spring should be in contact with the flywheel all the time is based on trying to determine whether you are supposed to lightly push in on the tuning knob (against the slack) to deactivate the Microtune circuit (as would be the case if a small gap in the contacts exists), or simply touch the tuning knob, as would be the case if the contacts were touching all the time. Since this is the first 200B I've ever seen up close and personal, I'm simply trying to establish what the intent was of the original design and build.

I am contending it is likely the latter (simply touching the tuning knob), as I believe that is the way Fisher would have wanted the feature to operate.


Dave
Click to expand...

When I pulled out my 200-b last weekend to run it for the day, I sat there reading the manual (for once!!) I did come across an entry that said simply touching the tuning knob deactivates the circuit. I didn't test my unit for that feature as I was sidetracked by the lamp issue. Even that didn't last long because I was too engrossed in the programming. So, I think you're correct Dave.

I'll get some pics up later today.
 
Well, I guess pictures are worth more than a thousand words.


As to my unit: I opened it up to address the lamp issue. Quick question: That MUTING knob. Is that an actual switch or just a variable pot. Looking at it more closely now, it looks like a switch. And if it is, well, it's busted. :tears:
 

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Not -- Thanks so much for the pics. It absolutely confirms my suspicions!

As for the muting control, it is in fact a pot with a switch on the back of it. In the unit I have, the lamp would work intermittently, or flicker due to the poor contacts in the switch. The switch has now been replaced to eliminate that problem.

Dave
 
Glad to help. And on my unit.....

Yeah, I checked the schematic: switch part of R-59. And yup, it's busted. Arghhhh!!!! Once I trace the circuit, I'll start a new thread on the subject. Thanks!
 
It's a Wrap

I was able to remove the L-bracket without de-stringing the unit, as once the rear retaining C ring was removed, the flywheel shaft could be pushed forward enough for clearance to un-mount and remove the L-bracket.

The rivets mounting the leaf spring contact and its insulator blocks to the back of the L-bracket are soft brass rivets. As suspected, the top one had broken at some point, and someone has attempted to repair that by soldering it back together. But it was so loose that it meant the bottom rivet had to supply all the tension. Being soft brass, it gave over time, so then the leaf spring itself was bent to try and restore the contact. But as the bottom rivet continued to give way, the condition only got worse.

With the L-bracket removed, the one rivet could simply be unsoldered, and the other removed with a hand drill. With everything apart, the L-bracket and leaf spring could be straightened back out again, and everything reassembled using nuts, bolts and fiber washers, for a very strong repair. After that it was reinstalled in the tuner to complete the job. The rear leaf spring now makes contact all the time with the rear of the flywheel shaft as originally intended, and the Microtune circuit now reacts by simply touching the tuning knob. All in all, about a half hour job. The pics show the results.

Not -- I've included a pic of the Muting control in this unit after the new switch was installed on the control, and the control then reinstalled in the tuner. The control must be removed and torn down to replace the switch on the back of it.

This puppy is ready to go!

Dave
 

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notdigital said:
Well, I guess pictures are worth more than a thousand words.


As to my unit: I opened it up to address the lamp issue. Quick question: That MUTING knob. Is that an actual switch or just a variable pot. Looking at it more closely now, it looks like a switch. And if it is, well, it's busted. :tears:
Click to expand...

Thanks Not for the pics, really appreciate it!
 
Dave you did a great job on this, my heartfelt thanks. Nice work on that switch and picture 4 just put a great big smile on my face! :thmbsp::D
 
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