HELP! Vintage Fender Princeton Reverb - PIC Heavy

Discussion in 'Amps and Cabs' started by deandavis, Mar 1, 2015.

  1. deandavis

    deandavis Member

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    Hi all,

    I recently was handed-down a Fender Princeton Reverb. I've dated the amp to 1968 based on the amp-chasis numbering (A21368) and this website.

    I'm looking to get this amp in top-working condition and was looking to get some advice from you experts out there.

    The amp currently seems to be making quite a bit of noise when plugged in. I'm not sure if this is because the cord is not grounded, or something else like the tubes or circuitry. In addition, when I adjust any of the amp controls there is quite a bit of static-noise.

    Lastly, the reverb doesn't seem to be working. The reverb-tank looks to be in fine working condition but I'm wondering if it could just be the tubes?

    I did some research through the forums and I'm thinking this amp needs a few things given the above conditions, but I'm looking to get some advice to confirm:

    1) Update the power cord to a grounded cable (currently 2 prong).
    2) Roll the tubes, and potentially replace the reverb tank.
    3) Clean the pots to get rid of the static.

    Is there anything that I'm missing in the above that might help get this amp in tip-top shape?

    Also, has anyone ever used the services of VintageFenderAmpRepair.com? I'm located in Canada, but thinking of shipping the amp down to them in California to do any of the necessary work.

    Lastly, I'm hoping that all you experts out there could give me some advice with regards to the specifics of the amp:

    A) What type of tubes would be best to put in this amp?
    B) Any ideas as to what kind of speaker is currently in it? Would it benefit from a update to say a Celestion G10N40?
    C) Is the age of the amp (1968) correct?

    Thanks very much in advance everyone! Here's some pictures:

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  2. TJNies

    TJNies Supporting Member

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    Nice! It takes a bit of effort to accurately date a PR, as Fender used whatever was in the bin. I had a blackline PR that turned out to be a 69 (rather rare).

    It is a dripedge version, so that confirms between 67-69. I am surprised there are no stampings on the tube chart, which helps narrow it down. I'd look at the transformers; they should have "606" then the next number is the year, next 2 are the week of said year. Example 606-8-01 would be first week of 68. But you have to take the latest of those, the label and speaker, and chassis markings, for reasons earlier.

    Tubes? Don't replace unless necessary; you have RCA preamps and Sylvania power and rectifier, which are fine (assuming they are working).
     
    Last edited: Mar 2, 2015
  3. deandavis

    deandavis Member

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    Thanks Tom! It looks like all the tubes fire-up okay, but I'm not sure how to confirm that they all work. As I mentioned, the reverb doesn't seem to work so I'm wondering how I can confirm whether it's the tube or the tank?


    Thanks!
     
  4. OiRogers

    OiRogers Member

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    It looks like the wiring connecting it to the chassis is frayed in one of the shots, if you are lucky it is just the wiring between the tank and the amp itself.
     
  5. deandavis

    deandavis Member

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    Thanks Mr. Rogers, but I don't believe it's the wiring to the chasis. The cords to the reverb tank seem pretty sturdy, and the connections solid. Here's another upclose picture:

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  6. slider313

    slider313 Silver Supporting Member

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    The speaker is a '72 CTS alnico. The power tubes are of Russian origin. I would get myself a pair of good USA made 6V6GTA's or 7408's. The transformer codes, along with pot codes, will give you a close idea of the completion date. Many amps have a stamp inside the chassis showing just that. I would update all electrolytic caps, check all the resistors and get a three prong power cord installed. Nice score!
     
  7. drbob1

    drbob1 Silver Supporting Member

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    Are you able to do the work yourself? If you're going to have an amp tech look at it, then plan on getting the caps replaced, try and figure out how the tubes are sounding, get things cleaned up. The reverb could either cables, wiring, tubes, or a bad tank (which might be repairable or might have to be replaced).
     
  8. Nonvintage

    Nonvintage Member

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    Your V2 preamp tube (the 12at7) looks to be in crooked also maybe clean all your tube pins with some DeOxit. Check out how to clean your pins on KCA NOS tubes website.
     
  9. tele_player

    tele_player Member

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    Since the reverb isn't working, and that tube is the reverb driver, it's the first thing I'd look at.

    To the original poster: does reverb make noise if you bump the amp? I'd also make sure the reverb cables aren't reversed.

    Robert
     
  10. deandavis

    deandavis Member

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    Thanks everyone for your information and advice. I'll try wiggling in the the reverb tube tonight and see if that helps. Right now, all the tubes light-up so I assume they're fine?

    I'm definitely not a pro in amps nor electronics so I'll need to ship the amp away to somewhere to do the cap work, cord modification, etc. Can anyone recommend an amp tech (preferably in Canada) that specializes in vintage Fenders? I've found KCAnostubes.com and VintageFenderAmpRepair.com but both are located in the US.

    Thanks!
     
  11. drbob1

    drbob1 Silver Supporting Member

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    Where in Canada?
     
  12. deandavis

    deandavis Member

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    I'm on the East Coast.

    I'd be willing to ship it, but I'm just wondering if there's anyone in Canada who would be an expert on this type of amp or whether I'm better-off shipping it down to KCA or VintageFenderAmpRepair?
     
    Last edited: Mar 2, 2015
  13. swiveltung

    swiveltung Member

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    Try different tubes in the reverb circuit.
    All your tubes appear they may be original... so it could very well just be that. Already noted the tube that is in crooked. Do you have the tube shields?
    The hum could very likely be the filter caps. They are in the silver can next to the Power transformer.
    You need a tech to change those filters.
    Check around... there must be someone up there to do amp work. Look under electronics repair.
    SHipping to USA and back can be expensive or slow and problematic at times.
    Just because the tubes light up means nothing. But keep your old tubes if they are good.
    That is a great little amp and definitely worth having properly tuned up.
    The other thing I just noticed. THE REVERB WIRE MARKED WITH RED SHOULD GO TO THE REVERB INPUT... IT APPEARS YOURS GOES TO T HE OUTPUT???? That may be the reverb problem right there...
    Your rectifier tube may be the wrong one... what is the number on it? Your tube chart calls for a GZ34 but that tube looks awful big in size for a GZ34.. may be a 5U4GB?
     
  14. arumrunner

    arumrunner Member

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  15. DaveKS

    DaveKS Member

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    You'll probably be best to start a new thread asking for qualified vintage amp techs in your area.

    Is this a old closet queen amp? More than likely if so, it's gonna need caps replaced.

    Don't go willy nilly replacing those old RCA preamp tubes unless needed, only a tech with tube tester can tell you for sure.

    Me I'd start with this Deoxit vacuum tube survival kit.
    [​IMG]

    It has cleaner/high temp conditioner and socket brushes.

    Clean all tube pins/sockets, straighten pins and reseat them. Also take Deoxit and gold and clean/condition up those RCA jacks going to reverb tank.

    Also be aware there are lethal voltages awaitng you on some of those tube pin sockets, if your not confident enough or willing to learn how to safely do this with out killing yourself let a pro take care of it.
     
  16. SBax

    SBax Member

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    The red reverb jack should go into the input.
     
  17. deandavis

    deandavis Member

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    Thanks so for the information and advice! You're 100% right, I do have 5U4GB in the rectifier tube. Should I switch it to a GZ34, or wait for the amp tech to do that so he can rebias at the same time?

    As for the reverb wire, that may very well fix it! I'll give it a try tonight - sharp eye by the way. I had no idea the red needed to go to the output. To be honest, I thought the rest was just a bit of oxidization on the cord but that doesn't seem to be the case.
     
  18. Dawg76

    Dawg76 Silver Supporting Member

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    Absolutely get that multi-cap can changed out ASAP. Filter caps should be changed out every 10-20 years. This amp is approaching 50 years old.
     
  19. deandavis

    deandavis Member

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    Thanks Dawg! What does the multi-cap do, and where is it located?
     
  20. VJF

    VJF Member

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    It's the cylindrical object you can see between your power tubes in your second picture.

    Filter caps remove current ripple in the power supply which would lead to excessive hum
     

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