Hartke HA3500 suddenly died (no output to speakers)

cptripps · #1 01-21-2012, 12:59 PM

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

curbowkid · #2 01-21-2012, 01:10 PM

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?

Cohacq · #3 01-21-2012, 01:11 PM

Is the cab working?

**fuzzy beard** · #4 01-21-2012, 01:13 PM

Call larry!

BassmanPaul · #5 01-21-2012, 02:06 PM

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.

BassmanPaul · #6 01-21-2012, 02:08 PM

Quote:

Originally Posted by curbowkid

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?

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.

RonChase · #7 01-21-2012, 02:10 PM

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

parsons · #8 01-21-2012, 03:49 PM

Quote:

Originally Posted by BassmanPaul

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.

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

cptripps · #9 01-22-2012, 09:52 AM

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!

rosskratter · #10 01-22-2012, 09:55 AM

...waiting for Larry Hartke to pop in on this...

billfitzmaurice · #11 01-22-2012, 09:57 AM

Quote:

Originally Posted by cptripps

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.

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.

cptripps · #12 01-22-2012, 10:41 AM

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.

BassmanPaul · #13 01-22-2012, 11:51 AM

Quote:

Originally Posted by parsons

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

Connected as I described in my post it's usual for the cones to move out.

cptripps · #14 01-22-2012, 05:28 PM

I've used that method for years, it always works well and it's a great tip.

Chasbo · #15 01-26-2012, 07:29 PM

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.