The history of a unit is something I'm always interested in. For my own pieces, I always make every effort to try and uncover past use and ownership information when I receive it. Short of that, I turn to the unit itself to try and decipher what information it might reveal of its history.
To that end then, I think that this 1800 reflected a heavier use pattern than outward appearances might indicate. My observations would include:
1. I think it was largely a one owner (or one user) item, meaning it was installed once or twice through out its life, and then used for a significant period each time. That would account for the minimum wear on connector screws, connecting jacks, and the like.
2. I also think it was installed in a cabinet for most of its life as well. That would account for its overall very clean appearance, but also a rather significant amount of old dust that I was always chasing out of various pockets. For example, when I had all the PS cans removed, there was a significant amount of debris revealed under the inside bell cover of the power transformer, that you just didn't really see or notice with all the cans in place.
3. The unit had clearly been serviced at some point as well -- but really quite strangely so.
I had originally thought that the B+ rectifiers had been replaced in the unit at some point, because while their solder connections looked original, they weren't the usual "top hat" type of component that is the standard you see as the originally installed device. However, the more miniature, gold looking devices that were installed in fact carried the same device number on them that Fisher calls out as their part number in the 800C Service Manual. So, while the original units were a much more modern device for the day when it was manufactured, they were still quite antiquated by today's manufacturing standards -- which would be in keeping for some of the last vacuum tube equipment that Fisher ever produced. Even their rating (600 PIV @ 1A) is antiquated by today's standards as well for the service they perform. By comparison, and even though the old diodes were still good, ultra-fast 1000 PIV 3A diodes now reside in their location.
One mystery of the unit was the low voltage DC heater/bias supply. As received, the unit had all original -- or at least, original style -- components installed in this circuit, but really very sloppily so. There was a tremendous amount of solder debris all around that area on the chassis and components -- very uncharacteristic for Fisher -- with virtually no solid mechanical lead connections made before soldering. This too is very un-Fisher like. It's almost as if someone was troubleshooting with a change-everything-out-until-it-works-again approach. OK, but then why were all the components still original components then? And they clearly were original components. The only thing I can think of is that maybe a component or two was changed, by swapping the old component for good ones from a junker unit. Beyond that, its hard to decipher much more from this area, other than this would all suggest that the work must have been done long ago. With modern components being so much better, and rather inexpensive at that, then why use (potentially) junker components -- unless the work was in fact done long ago when more modern parts weren't available yet. Either way however, you may recall that the output of this supply was so low, that for the longest time I operated the unit without the output tubes installed, and could not finish the initial assessment of the audio circuits until there was enough fire from it to light the heaters of the small signal audio tubes -- again suggesting that whatever work was done, was performed long ago. That's why this area was the first to receive actual restoration work.
Based on other observations, I believe that the unit got some good use, but as an audio component only. I frankly think that some of the problems in the FM section were potentially there from day one (if only intermittently so), which likely lead to reduced use of the receiver, or at least the majority of its use with the input selector switch in the AM, Aux, Phono, or Tape positions. The particular issues with the damaged IF transformer were a product of its construction, and clearly had never been replaced or repaired before it came to me. As Steve knows from behind the scenes communication, I even had to tear down one additional IF transformer to chase out one last ghost in the FM section.
The real indicator however, is the tubes. The power tubes had been changed out -- or harvested -- we'll never know. But all of the other tubes were all Fisher tubes, with a number of them weak or showing shorts, very weak, or even completely dead. Static unused time doesn't do those things to a tube -- use does. So at least the tubes that were in the unit certainly saw a fair amount of use time wise.
One thing I will mention -- and I hate to say this -- but based on the condition of the "All Fisher" tubes I received in at least my own 800C, I sadly suspect that some folks save these tubes up, and then populate equipment they are trying to sell with them, marketing it for max buck by the hook that it still has all its original (and good!) tubes -- as if to indicate low use time. In this 1800, one phono preamp tube (for example) was as good as the day it was manufactured, while the other phono tube was all but dead, and microphonic as heck. Now how does that happen if they were all original tubes? But hey, at least they were Fisher branded tubes! I'm not absolutely stating that foul play was at hand, but unfortunately, you never know anymore.
As for the face plate, it was in remarkably excellent shape -- again, owing to possibly cabinet installation, and (largely) single input use? Heck, for all we know, it could have been left tuned and pre adjusted to a favorite AM station, and turned on and off by a wall switch controlling the wall plug -- by why buy an 1800 for that service? Clearly, for the unit it received, it didn't require a lot of adjustment of the unit.
Steve indicated that he was pleased at the price he picked the unit up for. While he was never able to get any history out of the seller, that person may have at least had a conscience and had some knowledge of the work that would be required to restore it. Or, other than the output tubes, all Fisher tubes may have been sure to be included to counter act the known operational problems price wise. Well never know. I know with my own 800C, the seller was very good to provide history about the unit, but when I contacted him about the issues I noted that were counter to his marketing, I never heard from him again. As received, the FM section of the 1800 was completely dead, and it would have destroyed the output tubes before the small audio tubes ever warmed up enough to pass a signal!!
Some light might also be shed by knowing how you came upon this unit Steve -- and how it was marketed if that was involved.
These units are so rare, but its nice to know that there's at least one out there that looks so darn good!
Dave
