Help with repairing my 1965 Fender Deluxe Reverb

Discussion in 'Amp Tech Center' started by nealjyu, Aug 12, 2020.

  1. nealjyu

    nealjyu TDPRI Member

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    Hi! Thought I'd work on my 1965 Deluxe Reverb during this pandemic and sent it to an authorized Fender service center. After getting the list of parts which need to be replaced, I was informed Fender doesn't supply them anymore so I have to look elsewhere.

    These parts are what they don't have
    cap. 16 mfd/450volt -2pcs
    Potentiometer 999k- 2pcs
    Potentiometer 250K -4pcs
    Potentiometer speed control 3 meg -1pc
    Potentiometer reverb control 100k -1pc
    Potentiometer intensity control 50k - 1pc
    bolt mounting screw

    These parts they have
    Ac Plug
    Reverb Assembly

    I've also been checking sites like amplified parts and so far thet have the parts I need but i'm not sure which to get so that it will fit the amp properly. Also there's shaft type, audio or linear and other specs i'm not familiar with.

    Which brands to use? Which parts should and shouldn't be replaced as not all pots are broken? Etc

    Any recommendations will be greatly appreciated.

    Best regards,
    Neal
     

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  2. Jon Snell

    Jon Snell Tele-Meister

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    Authorised repair centres cover their/our backs.
    If I have an older Fender in for repair or any other make for that matter and one of the pots is scratchy, I am obliged to replace all of the pots otherwise in six months when another pot goes scratchy, I not only have to repair it for free but get frowned upon by Fender for not replacing them all, unless there is obviously no issue with any or the client requests not to replace them, in that case the fact is noted on the repair invoice.
    You will have a hard time trying to find replacement pots of those obscure values; 999k is 1M, 3 Meg is the problem one, may have to adjust the timing to achieve the desired result.

    Looks about the same age as mine.
     
  3. nealjyu

    nealjyu TDPRI Member

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    Thanks! i'm planning to have everything needed replaced and even if I decide to replace all the pots, I will have to get those parts by myself and if anything goes wrong, they will not have to repair it for free as the part is not Fender/ not distributed by them.

    For the pots, should I buy solid shaft? 24mm? audio or linear?
    I found a 3M pot in amplified parts but it's reverse audio

     
    Last edited: Aug 12, 2020
  4. Jon Snell

    Jon Snell Tele-Meister

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    Reverse Audio as it is called now (used to be Antilog) is fine.
    The shaft depends on the type of knob. If it has a set screw, use solid otherwise replicate the shaft that is already fitted.
    Seems odd that a Fender Authorised Service Centre cannot get those spares, if you can.
    Good luck.
     
  5. nealjyu

    nealjyu TDPRI Member

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    Thank you! Yes, we only have one authorized service center in the Philippines and they can only source parts which are either Fender or brands they sell. Both of which don't produce parts which can be used for vintage Fender amps.

     
  6. schmee

    schmee Doctor of Teleocity Silver Supporter

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    If a repair center doesn't have those parts, get your amp back immediately and take it to a good tech.

    So you took an amp in with no big issues and they say you need all that?
    For what type of parts look at the layout or schematic here:
    http://www.thevintagesound.com/ffg/
     
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  7. nealjyu

    nealjyu TDPRI Member

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    Nobody in the country has readily available parts here for the amp. There's no amp tech here who will source parts so I have to source them myself then have them troubleshoot it and repair as needed
     
  8. nealjyu

    nealjyu TDPRI Member

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    here's how the amp sounds aside from the scratchy pots. In real life, that feedback sound is TOO LOUD. Oh, and there's also no sound coming out while playing the guitar at times.
     
  9. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    Seems funny they can't fix it! While in the WestPac (69-70), we were in Subic Bay, (Olongapo), most every month for resupply. My friend had a Gibson amp that was giving problems, and none of the ET's on the ship would look at it. We talked to a music store there who had his tech look at it. We came back the next day, and all was well, the bill was approx $9, but he tipped the guy another $5. No more problems the rest of the cruise!
     
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  10. Antoon

    Antoon Tele-Afflicted

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    Replace all the pots? I would start with a good cleaning of all pots and contacts (tube sockets, grounding points, switches etc.). Than test the tubes and if it hisses or crackles replace the first preamp anode resistors. Good chance that it is working perfectly after that.

    Beautiful unmolested circuit BTW. That is how I like 'm!
     
    Last edited: Aug 12, 2020
  11. Wally

    Wally Telefied Ad Free Member

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    You need to make sure that those pots need to be replaced. I suggest getting the amp back while waiting for parts. Get some cleaner/lube and try cleaning those pots to do away with the scratchiness and perhaps other problems. We see new filter caps, but those bypass caps on the board need to be replaced, ime. We don’t see the bias cap. That must be replaced if it is original.
    A grounded cord and good general service along with the above may straighten out all of your problems. There is no way those pots should be replaced before one attempts to correct whatever problems they have, imho.
    Nice amp you have there...find a tech who is outside of the Fender organization would be my advice.
     
  12. Nickfl

    Nickfl Friend of Leo's

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    Service centers are for current products under warranty, a vintage amp should go to a tech specializing in such. Some authorized service centers may be run by competent vintage amp techs, but it sounds like the one you went to is not qualified to work on your amp.
     
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  13. dan40

    dan40 Tele-Afflicted

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    A vintage Fender like that would require 24mm, solid shaft pots. Make sure you check the schematic for audio or linear taper so that you get the correct ones for each location. CTS would be a good choice for a vintage Fender like that.

    I agree with the fellas though, it's doubtful that all of the pots need replacing. They may simply need a good cleaning first. Changing all of the pots at once may change the sound of the amp because there is some variation in the tolerances from one pot to another.
     
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  14. nealjyu

    nealjyu TDPRI Member

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    Thanks! How do you suggest I tell the tech to test the tubes?
     
  15. nealjyu

    nealjyu TDPRI Member

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    Thanks! There are 3 pots that are beyond repair. Got stuck or too loose. Do you recommend linear or audio pots?
     
  16. Lowerleftcoast

    Lowerleftcoast Tele-Afflicted

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    It depends on which pots you need. Do a search for a schematic and layout for the deluxe reverb AB763. The pots are shown there. They have their values listed. A = audio, L = linear, RA = reverse audio.

    Potentiometer 999k- 2pcs Audio (These are known as 1Meg pots.)
    Potentiometer 250K -4pcs Audio
    Potentiometer speed control 3 meg -1pc Reverse Audio
    Potentiometer reverb control 100k -1pc Linear
    Potentiometer intensity control 50k - 1pc Reverse Audio

    If you cannot find a Reverse Audio pot a Linear is the next best option.
    iirc, Fender used CTS pots. Alpha pots are an acceptable alternative. Your amp should have set screw knobs. Solid shaft pots. 24mm.

    IMO, your amp should have the old electrolytic capacitors replaced.
    Try to get name brand caps like Sprague, Nichicon etc.
    Here is a list.
    7pcs - 25uF 25v Axial capacitors (Cathode capacitors) This value can be anywhere from 20uF to 25uF. The voltage rating can be from 25v to 50v.

    1pcs - 50uF 100v Axial capacitor (Bias capacitor) This value can be anywhere from 25uF to 100uF. The voltage rating can be from 63v to 100v.

    Many older amps need other resistors and capacitors changed. Since you do not have parts available in your locality, you may want to have these on hand. Just in case.

    Capacitors
    2pcs 0.1uF 600-630V (I suggest Mallory 150)(Zoso and Orange drops are popular)
    3pcs .02uF 600-630V
    5pcs 0.01uF 600-630V
    1pcs 500pF 500-630V
    3pcs 250pF 500-630V
    1pcs 10pF 500-630V

    Resistors
    2pcs 1M 1w Metal Film (input jack)
    2pcs 220K 1w Metal Film (grid leak)
    10pcs 100K (Plate)(I suggest 1/2W carbon comp*)
    1pcs 82K (PI Plate)(I suggest 1/2W carbon comp*)
    2pcs 10K 2w Metal Oxide (B+ dropping)
    2pcs 1.5K 1w Metal Oxide (6V6 grid stoppers)
    3pcs 470R 2w to 3w Metal Oxide (This is 470 ohms not 470K)(6V6 screen)(Bias supply)

    Diode
    3pcs 1n4007 (Bias supply)(rectifier protection)

    *A word about Carbon Comp resistors. The good. The original resistors in your amp are CC. The CC resistor is the only resistor that may add Mojo. The temperature attained by a plate resistor is high enough to vary the resistance of a 1/2watt CC. As notes are played the resistance can vary, which in turn can make a sonic difference to the notes... Mojo.
    The bad. CC are not built as tough as other resistors. They are noisier than other resistors. With time the value can drift. They can become noisy and hiss. Wet locations like yours can be problematic. The moisture can impregnate the resistor which can degrade the value and cause hiss. In your location you may want to avoid the hassle of CC and use 1W metal film plate resistors.
     
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  17. nealjyu

    nealjyu TDPRI Member

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    Thanks! This is very informative and is what i have been looking for.

    Do you recommend replacing all capacitors and resistors to new ones or just the ones not working properly?

    If I decide to use the CC resistors, which ones do I buy then? I don't plan to gig with this amp. Will probably stay at home in a dry room.
     
  18. nealjyu

    nealjyu TDPRI Member

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    Any substitutes for these as I can only find metal oxide ones?

    2pcs 1M 1w Metal Film (input jack)
    2pcs 220K 1w Metal Film (grid leak)
     
  19. Antoon

    Antoon Tele-Afflicted

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    This not at all hoe I would go with such a great vintage amp but that's me. Do not start replacing components without reason. And if you have to at least buy NOS AB resistors and the original Stackpole or CTS pots. Everything can be got from Ebay. And pay a tech to test the tubes on a calibrated tube tester. Just have 'm tested and have him write down the measurement results. No need to replace the 2x25uf cathode caps unless they show signs of leakage.
     
  20. Lowerleftcoast

    Lowerleftcoast Tele-Afflicted

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    The electrolytic capacitors should be replaced now. They are the brown/orange paper looking ones on the board. The originals have two caps in one component. The replacements will be individual caps. Also the bias cap, which is on a small board near the power *on* lamp, if it has not been replaced already.

    The other caps, resistors, and diode should be replaced on a as needed basis.
    The reason for suggesting to have them on hand is because some of these will likely need to be replaced. It just doesn't make sense to pay $8.00 shipping on a 20 cent part.
    Metal oxide would be the next choice when metal film is not available.
    They are known as Plate resistors. They handle the B+ voltage for the 12a_7 tubes. If the original resistors have not drifted in value much and if they are not hissy, leave the original in place.

    Do not buy any NOS (new old stock) CC resistors.
    ______________________

    I noticed in your 1st post you have 2pcs 16uF capacitors listed. If you are only wanting to change out the 20uF capacitors, do not bother. 20uF is close enough. You will not hear/feel a difference.

    I am not advocating changing parts in the amp for the sake of change. I would rather you clean the pots and see if they can remain in service. The old electrolytic caps should be replaced if the amp is to be more than a museum piece IMO.
     
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