Fisher 1800 Receiver Information thread and roll call

Discussion in 'Fisher' started by RS Steve, Jul 14, 2016.

  1. Dave451

    Dave451 AK Subscriber Subscriber

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    The Fisher labeled 7591's in this 1800 looked a lot like the Sylvania's, but hard to tell from just the picture. Anyway, hope they're in good shape but, if not, I also have a matched quad of new production Tung-Sol's in the wings. The 1800 is shipping today. First vintage receiver for me with AM!
     
  2. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    3 of the tubes are definately Sylvania's and bets are the 4th is too.
    Here's the tube pic from the Auction. Note the 312 on the left most tube
    Clipboard01.jpg
    Nothing wrong with the Sylvie's. They made very good tubes.
     
  3. RS Steve

    RS Steve Tube Junkie Subscriber

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    This is where my 1800's are hanging out these days.




    20170829_172231.jpg 20170819_161217.jpg
     
  4. Dave451

    Dave451 AK Subscriber Subscriber

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    I agree, Larry, on all counts. By the way, Steve, what Klipsch speakers are those in your pic? Very nice set up and wonderful collection of 1800's!
     
  5. RS Steve

    RS Steve Tube Junkie Subscriber

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    I have Klipsch Belle's, Cornwall's, Chorus, KG4's, CF 3's, and Heresy's. The Belle's are the pretty ones, named after Paul Klipsch's wife.
     
  6. Dave451

    Dave451 AK Subscriber Subscriber

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    I have KG4's and really like them. Of your Klipsch collection, which do you prefer? Or does it depend on what they're hooked up to?
     
  7. RS Steve

    RS Steve Tube Junkie Subscriber

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    I really prefer my Cornwall's, it seems the Belle's like more power than 32 wpc or so. For high power solid state, the CF series is king!
     
  8. visman

    visman AK Subscriber Subscriber

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    Dave451 - just had a look at that listing - goodness that is a beautiful Receiver! Congrats!
    By the way I have Quartets which also work nicely with my 800C.
     
  9. Dave451

    Dave451 AK Subscriber Subscriber

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    Thanks, visman. It has arrived but I'm out of town til next week. Seller thoughtfully packed tbe wooden case separately. Will send some pics when i return and check if out.
    Dave
     
  10. Dave451

    Dave451 AK Subscriber Subscriber

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    Well, back in town and unpacked the 1800. Wooden case is very good. The unit itself was well packed and survived Fedex quite well. Chassis is in very good shape topside. Faceplate is in beautiful condition. The two 'original Fisher label" 7591's look tired (gray around the getters--can see through top of getter in one), while the two Sylvania's look good physically. Will test them on my B&K 707 (along with all the other tubes) and power test them in the amp once I have a good look at it and power it up with the Variac and DBT. Will send some pics tomorrow.
    Dave
     
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  11. Dave451

    Dave451 AK Subscriber Subscriber

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    Here are the "first look" pictures for my 1800, S/N 52468 T. Interestingly, the name plate says it's wired for 220-240 VAC, but it's obviously set up for 120VAC. As I said before, everything seems in good condition. Wood case is really good. Front panel and knobs are excellent. Chassis quite good on top.

    The work underneath looks pretty well done. The voltage divider cap (cardboard covered) has been replaced by the axials you see under the chassis, as has the 2x1000 uF bias cap. The couplers have been replaced, apparently with Russian paper-in-oils, if I'm not mistaken (K40y-9). The bias bridge has been replaced with a hardy-looking silicon unit. All the small electrolytics have been replaced under the chassis. Cathode resistors installed on the output tubes, but not grid protection resistors. The AM antenna appears to be intact, but has been re-mounted with wire ties onto the power transformer shield.

    You can see from the picture that the Fisher label 7591's look pretty tired around the getters. The Sylvania tubes appear in better condition.

    More when I power it up and have a listen! Let me know if you folks see anything to point out for further work.

    Dave
     

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  12. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Very nice unit, Dave. I would try to do something with the mount for the AM antenna. Mounted up so close to the power transformer, it won't bode well for AM reception......

    Congrats on getting such a nice unit!

    Dave
     
  13. RS Steve

    RS Steve Tube Junkie Subscriber

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    When they purchased these in the PX's, Fisher had a program where if you brought the unit in when returning from overseas, they would convert it back to 115V for free. (special bonus)

    1800-specs-Warranty.jpg
     
  14. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    The AM Mounting arm is between the Antenna and the Transformer. Get a couple of Nylon cable bundle hangers (like 8-10 per bag @ Home Depot) in the diameter of the Antenna. Mount to the arm and let it droop.

    The 1.2K 7W Blue Power resistor (1st blue one I've seen, usually green or tan) might be a bit tired from the looks of it. I'd suggest replacing with a 10W unit.
     
  15. Dave451

    Dave451 AK Subscriber Subscriber

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    Thanks much, guys. I'll have a look at the antenna mount (thanks for the suggestion, Larry). Yep, the 1.2K looks like it's given hard service, so I'll have a look at that. Thanks for the ad, Steve--fascinating stuff!. This one holds my personal record for number of tubes in a single unit: 22.
     
  16. RS Steve

    RS Steve Tube Junkie Subscriber

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    These rare beauties deserve nothing but the best when being restored, I'm sure you will make sure it's ready for its next life. We have the only two known original boxes for these, I would love to find someone that is the original owner and gather as much info as possible. The antenna clamps were just plastic wire holders originally, you should be able to find similar ones with no trouble like Larry suggested.
     
  17. Dave451

    Dave451 AK Subscriber Subscriber

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    Since the last look, I checked the tubes and powered up the 1800. Non-power tubes all tested good; mixed bag of brands throughout. One of the 12AX7's was labeled "Baldwin;" apparently an organ amp tube. The 7591's all checked good, but one of the older Fisher labels was significantly weaker on emission (my B&K 707 won't test mutual conductance for this type) compared to the others. I then powered it up fairly slowly with the variac and noticed nothing untoward.

    Lamps all work and had sound from both channels (as expected from the seller's description), the FM tuner was working well and quite sensitive even with just a clip lead antenna in the basement workshop. AM tuner worked as well, but considerable hash at certain points in the band--could well have been the antenna being mounted directly to the power transformer (as above) or noisy lighting fixtures. We'll figure that out. Everything sounded quite good, even into my bench speakers--no hum at all and very little tube rush in with the volume up full in the phono position.

    The Stereo Beacon lamp came on whenever the selector switch was in "FM Stereo Filter" position, but does not light in "FM Automatic" even with a strong, known stereo signal is tuned to max signal strength. Will have to look into that. There is a tube that controls activation of the beacon lamp that tested good. Any thoughts on what to look for?

    The FM signal quality doesn't fall off symmetrically away from maximum meter deflection. Noise happens quicker on one side than the other, so that, combined with the Beacon light issue, may indicate at least an alignment of the FM IF is called for.

    I decided I didn't like the work around the replaced capacitors; too many 'flying leads' and soldering not what I'd like in places, axial caps wire-tied to a 3 watt power resistor, etc. I want to leakage check the remaining multi-section can (C91A-D) with my Sprague TO-5 before I decide to stay with it, but it was quite cool during 20 minutes or so of power on. The other two have been replaced already.

    The B+ rectifiers appear to be replacements, R-170 B's, which are spec'ed at 1000 PIV and 2.5 amps, so they should be good. Work around the replacement couplers and small electrolytics looks good all around, so no worries there. The resistors in the bias/filament supply have not been changed despite the replacement silicon bridge and presumably higher voltage, so I want to check the bias voltages and 7591 cathode currents. One of the 7591 cathode resistors tests at 11 ohms. I'll probably replace them all with precision units.

    After I do the clean up work, I'll test voltages and power test the amplifier so see if I need to make any 7591 changes. I have a matched quad of Tung Sol 7591A's standing by if I need them.

    So, a little work to do before I bring it up to the listening room!
    Dave
     
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  18. Dave451

    Dave451 AK Subscriber Subscriber

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    DAVE G: I just re-read your thread for restoring RS Steve's 1800 (ca. 2015). You installed an overall bias adjustment pot/circuit that I'd like to duplicate for my 1800. Did you ever put out a schematic for that circuit? If so, I'd love to have it. Also, you mentioned that you had "tamed the unruly stereo beacon light," without further commentary. If you recall the specifics, I'd love to hear them given the situation above (no beacon lamp on FM automatic). I do plan to clean the relay contacts.
    Thanks!
    Dave
    PS I'm going to check out that 800C 'Service Bulletin' if I can find it to see what mods you made to the matrix switching circuit.
     
  19. Dave451

    Dave451 AK Subscriber Subscriber

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    After more close inspection, a good bit of work needs to be done and I have built Dave's IBAM to install. Rather than post a lot of detail, I'll deal with the things mentioned above and just post some notes and a couple pics when done--don't want to totally hijack this thread. If I get stuck, I'll start another thread.
    Dave
     
  20. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Dave451. The "800 service bulletin" thread is in the Forum Stickies. It's on the 1st list . Lots of good info in that section. Check the alignment of the MONO side 1st. Stereo demands that the MONO signal is strong and aligned correctly for the 38kc signal to lock to the 19kc. There is a relay in the diode matrix section that should have it's contacts (both sides) cleaned. Use strips of white paper soaked with DeOXit (D-5) and insert between contacts, then pull in one direction ONLY! Repeat until the paper comes out clean. You can burnish the contacts if necessary. Also the V7 6gk5 tube is in the Relay/matrix circuit. Make sure that tube is good. As I understand the "STEREO FILTER POSITION", The Stereo Filter position is used with a weak stereo signal to filter out some of the hiss/hash. It will also force the stereo/mono into stereo so you can pull in the weak signal. When you go to Automatic, it will revert to MONO unless a stereo signal above the threshold is available.
     

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