Intermittent problem with outputs on Hartke HA550

[gareth1982]

Evening chaps and chapesses; first of all, this is my first post on here in probably 4 years or so, but I did used to be a regular basschatter, then life, and a messy breakup seemed to get in the way of things and four years down the line, I find myself here again! So hi all (again). I will update my profile once I've typed this out....

I have a problem with my Hartke HA550 head. It works perfectly with no issues and tricks you into a false sense of security, then suddenly and randomly there will be no output from the amp to the speaker. It doesn't get warm, it hasn't been driven hard, and sometimes it will be fine for an hour, then the outputs (I've tried both) stop working. Signal is still reaching the amp incidentally.

It sometimes comes back on after a minute, sometimes 10 minutes, sometimes not until I try it again the next day, but it ALWAYS works again (perfectly...for a bit).

So, 'loose connection on the wiring to the outputs' i thought....lid off, nothing obviously loose,,,so I wiggle wires and it works fine (for a bit). I had it on the dining room table with the lid off for 3 weeks. I played various basses for hours through it, my ipod through it for hours too, and no issues.....so lyesterday I put the lid back on, but it back in it's casing and took it to rehearsal...it worked for ten minutes then the same thing happened once more!

I brought it home, back on dining room table, plugged in a bass and it works fine!!! It's GOT to be something loose or a dry joint maybe?, but I cannot see anything, and believe me, I've looked and wiggled and probed and everything seems solid and sound.

Any ideas?

Cheers

Gareth

[icastle]

There were a significantly large batch of circuit boards several years ago that had numerous dry joints and the HA550 comes from around that time - I had similar problems with an HA3000.

I narrowed mine down to the front panel (when it cut out, tapping the front panel bought it back to life) and spent an hour or so desoldering and resoldering all the joints in the vicinity of the front panel and, although its only a backup now, it always works without fail.

[gareth1982]

Fabulous advice within 12 minutes! Thank you very much icastle. I will get the screwdriver out (again) and have a(nother!) look.

I have a HA3500 as well which has been my main amp for years and this has NEVER let me down. I was hoping the HA5500 would be just as reliable but with a bit more oomph, but I haven't dared gig it yet because of this problem. I got it cheap anyway, so nothing much lost even if I can;t fix it.

Thank you.

[icastle]

No problem.

Something else that occurs to me is that it could be the Send and Return sockets playing up - not unheard of and the symptoms manifest themselves in the same way.

Try joining the two together with a spare guitar lead.

[Norris]

Thermal cutoff?

Edit: I'm not familiar with the amp, but if there's a fan is it working?

Edited November 26, 2015 by Norris

[gareth1982]

Yes, the fans (there are 2) are working fine, and the problem can manifest itself just after a couple of minutes at low drive levels when the amp is stone cold. I'm sure its a dry joint or loose connection, or the fx send/return (as has been suggested - thanks icastle) so will have a good look again and report back.

Cheers

[icastle]

Yet another possibility is a faulty speaker cable - Hartke heads have short circuit protection built in which will cut the output if it trips...

[RandomBass]

[quote name='icastle' timestamp='1448582802' post='2916709']
Yet another possibility is a faulty speaker cable - Hartke heads have short circuit protection built in which will cut the output if it trips...
[/quote]
Have you tried the head with different speaker cables and cabs? Does the problem happen with just one particular cab/cable? Could be an issue in the cab causing the short circuit protection to trip. Maybe.

[gareth1982]

Quick update; the problem manifests itself with any combination of cab and cable (and the cabs and cables work fine with my other heads), so it's definitely a problem with the head.

I'm gonna try the fx send and return connection trick first this afternoon, and if that fails, open it up again and meticulously check for dry joints. I will report findings!

[deepbass5]

Icastle has mention both things i would have offered up. Any send and return can break down opening the circuit, I periodically use industrial contact cleaner (being a spark sorry if you dont have this) spray a jack plug and pull it in and out, also wipe the jack off on a cloth to remove any dust or crud and do it again. I do this to all aux jack sockets because your fan pulls air and dust in through them. Always worth doing this once or twice a year. I have also bought a new speaker from EA at great expense import duty and tax, because of a farting noise from the speaker, eventually tracked it down to a loose cable in a speakon i had made up, not before also thinking like you that my markbass speakon socked had a joint problem on the board. Because the sound problem was intermittent this took me months to locate the source, not helped by the fact i had two identical cabs and two different amps both with similar home made cables

[gareth1982]

I've got some servisol in the garage so I will do as you suggest. Cheers.

Thank you for the advice. :-)

[Phil Starr]

A couple more suggestions.

I had the same problem with my HA3500 of the dodgy era. There are a number of fairly big electrolytic capacitors in the power supply circuit to the pre amp stages that are just soldered to the circuit board and are unsupported. Sure enough the joints had gon on one and the track was being pulled away from the board with a couple of others. I just resoldered them and pushed the leadouts through far enough for them to rest on the board. You could use some neutral cure silicone as well for support.

To find most intermittent faults get a freezing spray. by spraying individual components the contraction will often recreate the fault or temporarily cure it as the components and joints contract suddenly.

Good luck, always worth saving an old Hartke

Edited November 30, 2015 by Phil Starr

[gareth1982]

Thanks for all this advice chaps; I think I may have cured it....

There were no dry or loose joints on the output board or the fx send return board, nor were the capacitors loose or improperly soldered (I checked the main board too), BUT, and I think this is the crux, the 'tags'(?) (the bit that the tip of the speaker cable contacts) inside the Jack barrels(?) were filthy. A few cotton buds and some contact cleaner and they've gone from dark brown to silver. I haven't got time to play my bass thru it this week until rehearsal on Thursday , so I've currently got our Tv connected to it and outputted to my 4x10 cab. The Mrs says it makes a nice coffee table, but most importantly, we've had the telly on all yesterday and she has had it on for a few hours this morning (loud), and it hasn't missed a beat; I will give it a good blast with my bass at rehearsal on Friday for the acid test, but does this dirty contacts theory explain the problems I've been having?

[Dad3353]

[quote name='gareth1982' timestamp='1448888693' post='2918838']... does this dirty contacts theory explain the problems I've been having?
[/quote]

It could well be the problem (and the solution...); that's the trouble with intermittent faults that cannot be provoked, one never knows if they're cured or not. The acid test will be to use the head for a few rehearsals and gigs. If there's a new 'drop-out', try wiggling the speaker jacks to see if it brings back the sound. It is to be hoped that you've no further troubles, of course.
This is the reason for having a regular (every couple of years, at worst..?) check-up/revision by a technician (or oneself, if experienced enough; it's quite simple, really...). Folks using valve gear are more used to this, but SS amps still need the dust blown out, to help cooling, pots checked for crackles, sockets cleaned etc... We become used to modern stuff not needing routine maintenance, but there's a lot we can do as preventive work, whatever the technology. How many folks open up their PC and give it a good old go with the vacuum cleaner, eh..?

[stevebasshead]

[quote name='Dad3353' timestamp='1448894245' post='2918910']


...How many folks open up their PC and give it a good old go with the vacuum cleaner, eh..?
[/quote]None, I hope I was taught that there's a lot of static created around the hoover nozzle where the air rushes in so it's best/safest to blow dust away using a can of compressed air. Static and motherboards often disagree with each other...

[Dad3353]

[quote name='stevebasshead' timestamp='1448897238' post='2918957']
None, I hope I was taught that there's a lot of static created around the hoover nozzle where the air rushes in so it's best/safest to blow dust away using a can of compressed air. Static and motherboards often disagree with each other...
[/quote]

I've busted a whole speil of PC's, then, over the decades..! I wouldn't argue that a can of air won't do any good at all, but some of the innards I've seen need more of a scrubbing brush than a wee breeze..! A decent warning, of course, but I've personally never had an issue caused by static. Just lucky, I suppose.

[BigRedX]

[quote name='stevebasshead' timestamp='1448897238' post='2918957']
None, I hope I was taught that there's a lot of static created around the hoover nozzle where the air rushes in so it's best/safest to blow dust away using a can of compressed air. Static and motherboards often disagree with each other...
[/quote]

Can someone then please explain why sucking air causes static, but blowing doesn't?

[icastle]

[quote name='BigRedX' timestamp='1448901021' post='2919011']
Can someone then please explain why sucking air causes static, but blowing doesn't?
[/quote]

You're reading it too literally.
It's not the direction of airflow, its the item used to create the airflow.

A household vaccuum cleaner has a motor spinning around and will create static
A can of compressed air doesn't.

[deepbass5]

even when blowing is asked for sucking is preferred, well generally speaking

Edited November 30, 2015 by deepbass5

[stevebasshead]

[quote name='Dad3353' timestamp='1448900941' post='2919010']
I've busted a whole speil of PC's, then, over the decades..! I wouldn't argue that a can of air won't do any good at all, but some of the innards I've seen need more of a scrubbing brush than a wee breeze..! A decent warning, of course, but I've personally never had an issue caused by static. Just lucky, I suppose.
[/quote]
Luck plays a part in most things I guess In my ignorant youth I connected my amp and cab with a guitar cable at hundreds of rehearsals, running that poor bugger of an amp at near max against mad loud drummer + 3 equally mad loud guitars and it never fried once. But as soon as I understood the risk I didn't do that any more.

Thing is, going back to the hoover/static thing, it's what I was taught but googling it now and opinions are divided to say the least. I still won't risk it though.
[quote name='BigRedX' timestamp='1448901021' post='2919011']
Can someone then please explain why sucking air causes static, but blowing doesn't?
[/quote]
Explain? No in all honesty. But I can provide some conjecture that hoover manufacturers don't take into account whether the particular plastic their nozzles are made of are more or less prone to static. Or who knows, maybe what I was taught is out of date now and these days they do factor it in especially now that PC's are almost at "white goods" level and this is a likely use of hoovers. I would expect companies that manufacture compressed air cans for cleaning PCs to factor it in to their design and materials choices, so instinctively I trust those more than the multitude of hoover manufacturers and models. Right tools for the job and all that

Edited November 30, 2015 by stevebasshead

[Dad3353]

[quote name='stevebasshead' timestamp='1448903216' post='2919053']...instinctively I trust those...
[/quote]

Cynical old beggar as I am, I'd be wondering who has most to gain from the 'cans are safer' line..? The can industry..? Maybe. I'm not going to be throwing away empty air tins any time soon, however. Too ecologist; a soft brush, an old toothbrush, a bit of meths for the stubborn filth and a Hoover. Old school..? You bet..!

[gareth1982]

Update - the TV's still playing fine through the amp and the 4x10; we've got snooker on Eurosport at the mo then summat about the Orient Express in a bit. If the emap is gonna go off the rails, it will be during that programme, I'm sure....

[Dad3353]

[quote name='gareth1982' timestamp='1448913129' post='2919165']
Update - the TV's still playing fine through the amp and the 4x10...
[/quote]

At gigging volume, we trust..?

[stevebasshead]

[quote name='Dad3353' timestamp='1448906307' post='2919085']


Cynical old beggar as I am, I'd be wondering who has most to gain from the 'cans are safer' line..? The can industry..? Maybe. I'm not going to be throwing away empty air tins any time soon, however. Too ecologist; a soft brush, an old toothbrush, a bit of meths for the stubborn filth and a Hoover. Old school..? You bet..!
[/quote]I just give mine to me dear ol' mum, there's nothing she can't make sparkle again with a bit of vim and vinegar

[gareth1982]

Not quite! It had been cutting out at 'home practice' volume levels though previously, so I'm hoping that the fact it hasn't cut out since I cleaned the contacts is a good sign. Practice later in the week will be the real test. Thank you for all the advice given on here.