Fender Deluxe 85 Repair - No Sound

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by leray1, Jan 1, 2018.


  1. leray1

    leray1 Member

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    I was given a Fender Deluxe 85 and it powers up, but I get no sound. When I tap on the top it makes noise. So I took out the board and see some obvious issues (see pics). Anything else I should be worried about? By the way, this is my first attempt at repairing a board.

    [​IMG]20180101_120725_resized by leray1, on Flickr

    [​IMG]20180101_120756_resized by leray1, on Flickr
     
  2. Kyle B

    Kyle B Supporting Member

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    The resistor might actually be OK i.e. it might still work, just crumbled a little due to time & heat (replace it anyhow of course)

    I would check that the output transistors are good before putting power on it after replacing the cap.

    I'd also replace ANY electrolytic cap (like the one that exploded) if it shows any sign of leaking or bulging.

    Note EL caps (like the one that exploded) are POLARIZED. Meaning you have to get the +/- correct when you put a new one in. Fail to do that, and you'll see more wax paper strewn about your board (because they'll likely also explode...)
     
  3. leray1

    leray1 Member

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    Thanks! Where's a good place to get replacements?
     
  4. xtian

    xtian Member

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    Mouser.com or Newark.com is good for radial caps and 5w power resistors.
     
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  5. VaughnC

    VaughnC Supporting Member

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    You might have a basket case. One important thing to keep in mind is that an electronic componant can look good to the eye and still be bad. So, just replacing the parts that are visually bad most likely won't fix it as you need to get to the root cause. Very likely the output transistors were overheated...but you can test their junctions with an ohm meter or just replace them all with the shotgun approach. But there could be other issues that could fry your new output transistors the first time you apply power to the amp. Solid state electronics tends to be less forgiving as tubes...once a PN junction is fried, it's a goner. Good luck with the project!
     
  6. Blue Strat

    Blue Strat Member

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    FYI, the CORRECT way to do this is with test equipment and a schematic. Signal generator, oscilloscope, DMM, etc. You may get lucky and fix it by random replacement of components, or not. As Vaughn mentioned, replacing defective components is fixing the symptom...not the cause. Best of luck!
     
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  7. leray1

    leray1 Member

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    This morning I changed the two resistors and that one capacitor and I got sound, great sound (much better than my Peavey Studio Chorus). But, it was intermittent due to the fact that I didn't clean any of the pots before putting it back together. I took it back out, gave the pots a deoxit and let them dry all afternoon.

    I just put back together and all seems well, really well. This amp really sounds good. I do get a pop when I turn it off. The loudness of the pop correlates to the level of reverb. When the reverb is at 0 there's really no pop at all.

    Worst case, it blows again and I take it to a real tech to have it restored. For now I'm going to enjoy it while it lasts.
     
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  8. fenderpro

    fenderpro Member

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    Great that you got it up and running with minimal servicing. I had a similar experience with a Princeton 1 12 Plus recently.
    I was all set to jettison the chassis and use the cabinet and speaker with a different head. it turned that one wire had come
    unsoldered. now the amp is totally usable. gotta love it when that happens...
     
  9. TEPR

    TEPR Member

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    Haha guitar denter is a new one to me!
     
  10. leray1

    leray1 Member

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    Still going strong...I replaced the reverb tank on it today and it no longer pops when powered off. It cleaned up a few other issues - it's quieter and it no longer wants to feedback at low volumes.

    I've got replacements on the way for the two power capacitors and the rest of the ceramic resistors...should be here in about a week.

    Aesthetically, it was missing two knobs, the four bottom metal corners and the piece on the back that allows you to store cables and what not. The knobs are on their way, the corners arrived today and I made a piece for the back out of a pine plank (painted it black).

    All I'll really need to complete the refurb is a foot switch.
     

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