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Hartke HA3500 suddenly died (no output to speakers)

Discussion in 'Amps and Cabs [BG]' started by cptripps, Jan 21, 2012.

  1. cptripps


    Nov 29, 2009
    Coventry RI
    Last night at rehearsal my trusty 3500 was working fine for about 4 songs then stopped producing sound altogether without warning. The amp still powers up, fan is on, face lights up, compressor shows input (green to red on the LED) and the amp was just barely warm.

    I took a quick look inside with the top cover off today, there is no odor of cooked electronics and no hotspot damage or burnt caps or resistors that I can see. Also, on power up the main amp relay still kicks in as usual but there is just no output whatsoever.

    Does anyone have a clue where I might begin to troubleshoot this? I'm handy with a soldering iron but I'm no bench tech so if it's too hard to diagnose I'm pretty well screwed :(
  2. curbowkid

    curbowkid Guest

    Jun 27, 2011
    Brooklyn, New York
    You might have blown the fuse. I have the 2500 model. In the back above the input line jack there's a little thingy mahwhatsit with a number on it. That's the fuse. Maybe change that?
  3. Cohacq


    May 14, 2010
    Is the cab working?
  4. Call larry!
  5. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    You can test the cabinet with a 9V battery. Tip of the speaker cable to the positive sleeve to the negative should give you a healthy clunk. Normally the cones will move out away from the magnet.
  6. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    The power fuse is fine everything seems to power up OK and if the protection relay engages then I would think that the amp is OK too.
  7. RonChase


    Aug 15, 2008
    Yeh Larry is a real cool and approachable dude,On my Hartke the front 1/4 jacks on the inside plug into a motherboard(I dont know what else to call it) but the jack seemed like a plug similar to a cordless phone battery well it kind of worked loose I pushed it back in and been fine since.These things are work horses so It is probably something easy.Good luck I am just relaying what my problem was when I had a close circumstance.Good luck
  8. parsons


    Feb 22, 2008
    depends on what polarity you give it. Reverse it and the speakers move in. Either way, itll produce sound and show continuity.
  9. cptripps


    Nov 29, 2009
    Coventry RI
    The cabs are good, for sure. I did some re-seating of the many harnesses to the main AMP board, the preamp board and the input jacks, the tube socket, etc.. Also, not that this was necessarily the issue but some of the transformer taps that come off the back of the AC/fuse sled were barely halfway on so I slid them all in tighter. I wish I knew which thing it specifically was that caused the issue but I did all of that with the power off so there was no way to tell.

    So far it seems to have come back to life. I won't really know until I put it through the vibrating paces at rehearsal but I hammered on a bass through it for a few hours last night (with the amp on the floor in disarray) and I think it was down to just something loose. Thanks for the input everyone, I hope this thread can help someone else with a similar issue!
  10. Ross Kratter

    Ross Kratter Gold Supporting Member

    Dec 31, 2010
    New York, NY
    Artist, RS Berkeley, La Bella Strings and Phil Jones Bass Amplification
    ...waiting for Larry Hartke to pop in on this...
  11. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    It's possible that there was no power to the output stage rails but there was to the lower voltage supply rails for the rest.
  12. cptripps


    Nov 29, 2009
    Coventry RI
    I am thinking this too. It was stone silence, not even a hum or hiss. Dead outputs but everything else seemed to be on and running. Weirdly though, the output transistors were heating up. I think it was either what you stated or the harness on the amp board that runs over to the speaker jacks. Like I said, everything was a little loose. I gig and use the head a lot, it's not surprising to me if something just got loose from load in/out.
  13. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Connected as I described in my post it's usual for the cones to move out.
  14. cptripps


    Nov 29, 2009
    Coventry RI
    I've used that method for years, it always works well and it's a great tip.
  15. Chasbo


    Mar 10, 2011
    CPTRIPPS: My Hartke HA3500 does the same thing. I would lose audio but still have led lights, fan, etc. J just bought this Amp in May 2011 and it has rarely left my home. I called Sampson Tech and spoke with a rep. Since it is under warranty, Sampson placed a Fed-Ex pickup ticket, I packed it for shipping and Hartke repair center has had it for 3 weeks. I love Hartke equipment and I hope the repair is permanent. I assume that I will have to haul around a backup amp in fear of the Hartke going down during a gig.
  16. sperely1


    Nov 7, 2011
    Hey everyone, I have this Hartke HA3500 head. I have used it for P&W for over a year, worked fine. 2 weeks ago it crapped out and i get no output to the cab.

    First I tested the cab with another amp...worked fine. when turned on all lights are on, the fan is on and the compressor goes green to red when plucking a string. I did the send and return test. When plugging the bass in the return "hole" i got amplified sound. When i ran cable from the "send" to the cab, i got silence. I believe i have narrowed it down to something faulty in the preamp. I quickly checked the caps and trans for brakes or looseness, nothing doing. all looks fine. What else could i be missing?
    BTW, i recently plugged in the passive input and maxed out the EQ and could hear a faint "farting" noise out of the cab. Any suggestions would be greatly appreciated.
  17. zwish


    Nov 3, 2009
    I'm in the same boat here. I recently acquired a HA3500 head that powers on, fan turns on, and the compressor flashes, so a signal is passing through the amp. The problem is that there is no sound getting to the cabinet. I've tried multiple cabs, cables, and basses, so it's definitely the amp. I've also replaced the preamp tube inside the amp. Any ideas of what to check? Thanks.
  18. wounded horse

    wounded horse

    Aug 5, 2009
    Get the mains rocker switch checked out. I believe there were issues, well documented.
  19. Homerocks


    Dec 5, 2014
    Was there ever a solution to this?

    I also have a HA3500 with the same problem. The amplifier powers up and works great for a few minutes, and then it stops outputting to the cabinet. The fan stays on, all lights on the front remain on, and the I can see the compressor working. If I power the amp off for a few minutes, it will work again then stop outputting after a couple minutes.

    Any ideas?

  20. Bob-I


    Sep 12, 2014
    You won't get enough to drive a cabinet from the send. Run the send into another amp of any type. I use a powered cab for this test, but a guitar amp, bass amp, PA, even your stereo,will work.

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