Question about Audio & Video Receivers

1 Answer

Hafler power amp has one side out. Would like local repair.Series 9300.Approx.10-15 years old.Not used much.Second time to blow.Runs 4, 8om speakers including 2 bose 802,s (no bose controller or eq in system) and 2 REF Kseries 8om speakers.Used as external amplifier to Yamaha home theater amp to drive mains in system.Thanks,Byron Pritchard,Denver colo.

Posted by on

1 Answer

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

Just discovered same problem with my Hafler DH-200...right channel out but no obvious problems inside (no loose/burned wires, components, etc). Driven by Hafler pre-amp, but definitely power amp problem.

Posted on Dec 28, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

To Mr. Hyde: you appear experienced with Bose 501 Series III speakers. I need to replace a burned out glass bulb fuse inside the right speaker, the fuse for the woofer I believe. I think that you said that...


Hello whit_hughes,

Just received your request for some information regarding Bose 501's......... Series III. Your looking for te manufacturers part # for the fuse which is in line with the woofer? The fuses used ON the Series III Crossovers (hard wired/soldered directly to crossover board/componants) have been Identified as BUSS #2494, 2amp, Quick-Blow Glass Tube Type Fuses. The fuse which is in-series with the woofer & the fuse which is in-series with the pair of tweeters are the same! In theory this means that the woofer is capable of twice the wattage of the tweeters due to the tweeters being wired in series with each other..... which in turn divides the power beween the two equaly. On the woofer circuit there is only the one speaker or voice coil obsorbing the power. The woofer circuit being wired in parallel with the tweeter circuit again splits the power between the two cuircuits..... so in an ideal situation the woofer sees 50% total input power while the tweeters each see 25% total input power;;;; totaling 100% total. The way Bose has fused them in the Series III's is such that each branch can obsorb a total of 2 amps before shutting down each indivigual branch. This can be adventageous..... should peak power be exceeded causing loss of full load abruptly, Amplifier Power Output Transistors usually blow..... however when only half of the full cuircuit shuts down due to peak power exeeding limits causing one fuse to open (blow) ... the actual impedance (resistance) of the speaker increases protecting the Amplifiers Output Transistors! Thats the reason for the 2 fuses. Each of them are identical. They are soldered into place.... via the wire which is attached to each end of the fuse. (Note; the fuse "kit" Bose is trying to sell you is an external in line fuse holder for each speaker {costing 1.29 each} & 2 fuses for each holder, One for now & One for Later aftr it blows {costing 1.00 each}..... costing Bose 6.58, neting Bose $13.42 Profit!!!! Keep in mind that this fuse WILL NOT FIX YOUR PROBLEM EITHER! DUE TO THE FUSE WHICH IS PRESENTLY BLOWN HAS NOT BEEN REPLACED!!!!! ) The one that has to be replaced is on the crossover... not between the Amplifier & the Speaker Enclosure. Tools required = 1 Long Big Straight Blade Screwdriver to pry off speaker grill, 1 Phyllips Screwdriver to remove screws seccuring woofer to encloser... be carefull not to damage/tear gasket, 1 pair side cutters to cut blown fuse out of crossover curcuit, 1 pair needle nose pliers to attach NEW fuse to crossover curcuit, 1 soldering Iron & a small piece of solder to re-solder fuses leads securly to crossover curcuit. ( replace gasket, woofer, screws, & speaker grill. ENJOY! Should additionaL informaton be required please let me know.... you'll have to leave me your e-mail address for pictures or drawings.... as I don't think they can be sent through this site. Hope this helps ya..... Its an EASY JOB...... you CAN DO IT! & will be glad you did when your done, they'll sound GREAT! ) GOOD LUCK!

Jun 22, 2011 | Audio & Video Receivers

1 Answer

Hafler 9270 stereo amplifier produces no audio when powered up and connected to speakers. So far, I have only checked the fuses, but am lost as online articles show continuity on my multimeter, however the...


0 ohms is a dead short. That's bad unless you're measuring a single conductor end-to-end.

Register and download the SERVICE Manual for free at retrevo.com

http://www.retrevo.com/support/Hafler-9270-Amps-manual/id/23316bh035/t/2/

Did it ever work?

If not, EVERYTHING is on the table as a possible cause. This is a big dumb amp with nothing but a power switch. Perhaps your source is the issue. Or the stereo/mono switch.

If so, what preceded the failure? Did a control get touched? Smoke?

The Hafler could be protecting itself.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

==

NEVER USE MAXIMUM VOLUME FOR TROUBLESHOOTING.

Turn the SOURCE volume control to something medium.

The errant switch, control or condition may change and you will suddenly release the amp's full power and possibly destroying your speakers. If a signal isn't audible at 1/2 volume it's probably not there.

Carefully examine the front panel for clues like a misplaced Mute or Tape Monitor control or Multichannel Analog Input selected.

There is a good chance that a common control may have developed a high-resistance or 'dead' spot through idleness and is causing your symptom. Turn the POWER OFF and operate every control throughout its range a number of times, especially rarely-used ones like Tape Monitors and the Mute control.

Turn the volume to something reasonable and see if that helped.

May 24, 2011 | Audio & Video Receivers

1 Answer

We have a Denon AVR 1603 approx. 7 years old. Over the past few weeks, when we have been playing CD's the power clicks off. So we have to turn the system on again from our universal remote. Today,...


Any device has only so many self-protection cycles in it before it gives up the ghost.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

May 15, 2011 | Denon AVR-1603 Receiver

1 Answer

Right speaker does not work on both A and B


Before doing anything else swap the speaker connections over to make sure that the problem is in the amp and not the speaker / speaker cable.
If that doesn't solve it then it is most likely an internal fuse blown on the amplifier circuit board - they are little tiny glass ones, obtainable from most tv repair shops, but it is important to get the right power rating. Also some of these fuses are 'quick blow' (go instantly there is a fault) others are 'slow' or 'time' blow - take a second or two before they actually blow - make sure you get the right one (timed usually have the letter T next to the power rating)

Mar 22, 2011 | Technics SA-DX930 Receiver

1 Answer

My jbl control now speakers high keep blowing ...why??? im using it with harman kardon 3490 amp, this is the 3rd time i would be getting them repaired...


Little speakers like these won't dissipate a lot of power without blowing and real bass isn't their thing. At best they might work out as satellites. The 3490 and your listening habits could be too much for them.

Dec 22, 2010 | Audio & Video Receivers

1 Answer

Lost low end


Fuse don't break when the blow. If they blow you get NO sound, not distorted sound.

I think you need to bite the bullet and move on with isolation of the (probably dying) woofer. Remove it and swap it with the other one to prove it. Observe the polarity of the + and - wires on the back of the woofers.

Apr 27, 2009 | Audio & Video Receivers

1 Answer

I have a Harman Kardon AVR 235 Receiver that go's into Protect


To avoid making the avr go into protect mode when you power up your Hafler 4000 that is connected in the avr's pre-out, you must power up the set up in the correct sequence.

1. Turn off your avr
2. Connect Hafler 4000 to the avr's pre-out it it is not yet connected
3. Turn on your Hafler 4000. The avr will not go into protect mode becasue of the transients from the Hafler because it is still not powered on.
4. Turn on you avr. There should be no more transients from the Hafler at this stage unless it is not functioning correctly, so the avr shouldno longer go into protect mode.

Dec 08, 2008 | Harman Kardon AVR 235 Receiver

Not finding what you are looking for?
Audio & Video Receivers Logo

Related Topics:

201 people viewed this question

Ask a Question

Usually answered in minutes!

Top Audio & Video Receivers Experts

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

The Knight
The Knight

Level 3 Expert

68323 Answers

yadayada
yadayada

Level 3 Expert

61037 Answers

Are you an Audio and Video Receiver Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...