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Thought my Vox Pathfinder 15 was junk

Discussion in 'Amp Central Station' started by El Serio, Jan 25, 2021.

  1. El Serio

    El Serio TDPRI Member

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    About 15 years ago my brother gave me his Vox Pathfinder 15 amp (pre reverb). It was awful, couldn't play chords at all without extreme breakup. Had to turn gain way down and play one note at a time to use it at all. Also the tremolo didn't work and the input jack was shorted out.

    Fast forward to late 2020- I'm looking at small vox amps when I think, maybe I should try fixing the Pathfinder first? Replaced input jack with a spare one from a guitar, but it still sounded awful.

    Searched the internet and found on TDPRI info about a malady called "Cambridgitis" due to bad opto-couplers.

    The source quoted in the prior thread no longer had the part

    Found this part #VTL5C3 for about $10 shipped on eBay
    Installed it and now I have a good amp. It sounds great to me.

    Thanks to those who have shared this solution in the past.
     
    Last edited: Jan 25, 2021
  2. teleman1

    teleman1 Friend of Leo's

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    Did that fix the tremolo also?
     
  3. bender66

    bender66 Poster Extraordinaire

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    I picked up a non working 15 chassis here. The part to fix was $8. I've got some donor radio cabinets I'm thinking of installing it into.

    I own a 15R and a 15 SMR. Love 'em.
    20191220_145921.jpg
     
  4. El Serio

    El Serio TDPRI Member

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    It fixed the tremolo, I can also turn the gain up and get normal gradual response instead of complete breakup when only turned 1/8 of the way up.

    This amp loves my Tele now
     
    Last edited: Jan 26, 2021
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  5. unixfish

    unixfish Doctor of Teleocity Silver Supporter

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    $10 fix. Nice!
     
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  6. Chiogtr4x

    Chiogtr4x Poster Extraordinaire

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    I first ( maybe 2000) bought a used Cambridge 15 and used it in my ( then new) own band, and it was a little rockin' beast, for maybe 6 mos.

    Then it got 'sick' lost volume, got super distorted, and I just shelved it, played one of my other amps.

    Around 2006/7, I joined TDPRI and started constantly reading, over the years, about the Vox Pathfinder, and how folks were ( are!) nuts about it.

    Not sure when, it was a while, but I got my Pathfinder 15R used maybe 2012, for $85 on CL, sounded great.

    I did not notice 'till after purchase, but it had a 4ohm Crate speaker in it, instead of the stock one.

    So I still had the Cambridge amp, took the 8" Vox/Celestion Bulldog out of it and put into the Pathfinder. Fantastic sound- 6-7 years of gigs with it.

    *I actually threw out the Cambridge chassis ( just frustrated!) years ago, kept the cab, which now was modified by a buddy, to fit a 10" Celestion as a matching extension cab for the PF15R.
    ( but I still prefer the sound and portability of the 8" that's in there- my baby!)
     
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  7. Marc Morfei

    Marc Morfei Friend of Leo's Silver Supporter

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    I have a Pathfinder 15R (with reverb) that had problems. After extensive research, I discovered the optocoupler issue. It took a lot of sleuthing to find the part. Apparently you can't get the original part, but there is an equivalent. Went to fix it, and discovered the 15r does not have an optocoupler. Turns out it was a bad volume pot. Replaced the pot (also not easy to find), and it is 100% good. Might still have the replacement optocoupler lying around here somewhere....
     
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  8. nojazzhere

    nojazzhere Doctor of Teleocity

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    Years ago, I bought a non-working Pathfinder 15 (don't remember if reverb or not) I love my other two PF 15Rs, re-housed with one 12" and the other with four 8" speakers. The non-working chassis is still in a closet, I never got around to getting it fixed. Maybe I should dig it out and do something with it.
    BTW, those two re-housed PF 15Rs are all I use to gig with anymore. (or, at least DID gig with)
     
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  9. Midnighttoil

    Midnighttoil Tele-Meister

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    Mine is resting inside the closet where my wife hid it. Time to go spelunking!
     
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  10. El Serio

    El Serio TDPRI Member

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    If you're comfortable soldering, it's a pretty easy fix. The most time consuming part is getting the circuit board out.

    In order what I did is:

    Remove screws from wood piece that goes across the back (this has 3 jacks in it)
    Remove speaker wires
    Remove 2 screws on top as well as all knobs and the nuts on the pots and jacks
    Remove screws from aluminum angle (heat sink?)
    This allowed me to pull the circuit board down out of the chassis
    In order to access the back of circuit board I also had to remove ground wire and transformer mount screws.
    There was only one opto-coupler, it looked similar to, but a little different than the new part, black piece with 4 leads
    Unsolder old part and remove - note orientation
    Consult spec sheet for new part to make sure I got it in the right direction - one leg was shorter than the others - if I recall correctly it went in the bottom right hole (the one nearest the transformer)
    bend legs to fit holes and solder into board, trim off excess length

    Reassemble in reverse order

    Plug in tele and turn on - life is good
     
    Last edited: Jan 26, 2021
  11. El Serio

    El Serio TDPRI Member

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    I think the optocoupler is part of the tremolo circuit. Does the 15R have trem? If not, maybe that's why it didn't have one.
     
  12. mkdaws32

    mkdaws32 Tele-Afflicted Gold Supporter

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    I bought a Pathfinder 10 combo (6.5" Bulldog) for a cheap "workbench" amp - just something to make some noise while adjusting pickups and working on guitar electronics. I really didn't care about the tone and the price was right for my intended use. Well, I was genuinely blown away by this thing. It sounds fantastic. Those Bulldog speakers are amazing - they sound huge for the size and have a full, but tight bass response. A little gain on the OD channel and an EHX Hot Wax in front gets me insanely good classic rock/blues/classic metal tones. Not good for the price or the size - just good. Period. It replaced a Mustang II, which was fine for what it was, but this little tiny Vox just sounds bigger, less boxy - more open. I will definitely be trying some recording with this thing.
     
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