Question about MTX Thunder 81000D Car Audio Amplifier

7 Answers

Amp powers up but no sound

I Have a 1800D MTX that powers up but no sound. All power supply fets (HUF75339P) and out put fets (SSP45N20A) are new with no leakage. Rails, LEDs 463, 339 power up gain is good and RCAs are tight.

Posted by on

  • 5 more comments 
  • ranjonzun May 25, 2009

    I Have a 1800D MTX that powers up but no sound. All power supply fets (HUF75339P) and out put fets (SSP45N20A) are new with no leakage. Rails, LEDs 463, 339 power up gain potentiometer is good and RCAs are tight. Coils and caps are solid. There is no corrosion or cold solder joints. Flexing or twisting board changes nothing and there are no burn or scorch marks.

  • ranjonzun May 25, 2009

    Unit powers up, caps charge and it idles with out drawing excessive current or over-heating. Signal source is good, speakers check out, amp is a mono block class "D" that has no internal relay.

  • ranjonzun May 25, 2009

    There is no reset button only a compression switch to minimize hi-volume clipping.

  • ranjonzun May 25, 2009

    Source and drain of Fets are receiving hi-voltage from power supply. No voltage, sound, tick, or turn-on thump from out puts. Choke coils are securely soldered in place.

  • ranjonzun May 25, 2009

    No faulty connection between speaker terminals and Mosfets.

  • ranjonzun May 25, 2009

    The unit powers up. I have 155 volts (+77.5 on the source and -77.5 on the drain with respect to ground). This is a class "D" amp that uses MOSFETS for out puts not Transistors.

  • ranjonzun May 26, 2009

    Thank you Palaboy, your solution and advice sent me in the right direction. The pre-amp power supply was dead so no voltage for FET drivers or pre-amp was present.

    Thanks: Ranjonzun

×

7 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 5,807 Answers

Be sure you have a 12v supply on the remote terminal, turn it on measure the voltage at the main amplifier output transistors you should measure at least +25 v on the collector of Cxxxx and -25 v on the collector of Axxxx if you can have all of the above i dont believe that sound will not be produce in your speaker.dont forget to rate me when it works, thanks for using fixya!

Posted on May 25, 2009

  • Rommel Cana
    Rommel Cana May 25, 2009

    ok, try to look for power supply of the preamp it should have at least +12 and -12v

×

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 1,952 Answers

Check wire connection then sound board is failed reconect the wire................

Posted on May 25, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 1,383 Answers

Check there is not any faulty connection between speker and amplifier.

Posted on May 25, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 3,866 Answers

Well if all check out you got bad source somewhere? Have you used a probe on those caps? You said the rails where okay how did you verify this? Are you getting power out of the speaker leads?? Are you checking source?

Somethings gots to be hooked up wrong on the wrong lead . This is a mystery!

Posted on May 25, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 1,011 Answers

Check the reset botton that is located in the back and hard to see.You will nees something small to check it.

Posted on May 25, 2009

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Sergeant:

    An expert that has over 500 points.

  • Expert
  • 296 Answers

Hi
One of two things spring to mind.
One; power from head unit on signal (acc)lead, check voltage there, usually the Centre of the three, (power, signal, earth). try a bridging wire from live to signal see if the amp fires up.
Second is that either the head unit is dead on the output or the speakers are blown (straight check with ANY speaker will test this the quickest way).
Can you get your hands on a similar head unit for 5 minutes and swap over to see if that fires up the amp?
Bridging a 4 channel amp down to 2 should consist of Channel 1 + to speaker 1+ and then Channel 4 - to speaker 2 - then running a speaker wire from speaker 1 - to speaker 2 +. That is how I have my 2 channel amp bridged and I run 2 Kicker Comp CVRs rated a 400rms each with a 1800 watt power acoustik amp when bridged will put out 780rms. So try that setup and if your going to protect on your amp you might have to bridge channel 1 and 2 into speaker 1 and channel 3 and 4 into speaker 2. Also the booklet that came with the amp will help you trouble shoot as well.
regards

Posted on May 25, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Brigadier General:

    An expert that has over 10,000 points.

  • Master
  • 8,619 Answers

Hi

I believe something is either loose or broken, you can check it when you remove the case and extract the circuit board. Clean all parts thoroughly using a good electronic or contact cleaner, like crc qd electronic cleaner as it is cheap and available at most auto supply stores, just make sure whatever cleaner you use is not industrial duty and is plastic safe.

After the entire thing is cleaned (coils, capacitors, anything resembling dust) check with a magnifying glass for any broken solder joints, you can also very lightly touch components and see if they move. Also check for any broken solder joints, extremely dirty contacts, corrosion, or dry capacitors. You can usually locate dry caps by looking for corrosion around the cap and discoloration on the top of the cap.


Please do accept this solution and revert for further assistance.

Thanks
Rylee

Posted on May 24, 2009

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Any sub's I hook my mtx jackhammer jh1200 up to instantly are forced down and eventually fry. Why is my amp doing this?


This problem is caused by one or more of your output devices (FET, Transistor, or IC) is shorted and causing the power rail to be connect through your speaker. Your amp boosts the 12v supply to a much higher +/- voltage rail which powers the amp's outputs. When the amp is shorted or overheated to a point of destruction you can end up with this problem.

It will need to be repaired by a technician.

Mar 03, 2015 | MTX Car Audio & Video

1 Answer

I have a mtx thunder 7801 series amplifier well i got a stereo from someone and i didnt know it a the time but it had the wrong plug in the back of it so when i hooked my amp up to it what i thought was...


The short answer is probably yes... easily, probably no. If you are lucky and only have one or two shorted transistors, then you can cut the leads on those and see if it powers up without blowing a fuse. Also check for shorted diodes and burnt resistors. If all FETs (or most of) the FETs mounted to the heat sink are shorted then it is probably not worth taking the chance putting the time and money into fixing it, just to have it smoke again. Also they are likely in parallel so it is a little more difficult to determine the bad one as they may not all be bad. Measure with an ohmmeter and find the one with the lowest resistance and remove that first and keep going until you believe you have gotten them all. Normally repairs like this are not for someone with little or no experience on amp repair, but if you feel like taking it on, good luck!

Apr 20, 2014 | MTX Car Audio & Video

1 Answer

I have 4 mtx 9500 12in subs 2 of them is on a mtx 92001 and the other is on a mtx 4001d . would it be better to run all four on the mtx 4001d. for more power and a better sound or how should i run this set...


NEVER mix different power amps. Depending on the ohms of your subs, sell one of the amps, up to you. The 4001 has more power, but either amp will do the job, the amp needs to see a 1 ohm load, so your subs have to be dual 2 ohms, or single 4 ohms to do this. If your subs are dual 4 ohms then you will have to run your amp at 2 ohms which would be have the power, or a half an ohm, (Not Recomended) and be at double the power. You may be able to do a competion sound off and just "Burp" the subs, but at a half an ohm, dont expect to listen to it to long before it goes into protect and shuts down.

Sep 06, 2011 | MTX Thunder Elite TE4001D Car Amp

2 Answers

When i started to plug my battery in my amp made


you have blown the actual filters that make the sound. a amp is basically a filter with the same filters on both channels on each side of the inside of the amp - channel 1 and channel 2, that pop was in the heat sinks of the amp usually. if you have replaced the fuse in this amp and you get no on light, the internal amp is in need of repair

Oct 24, 2009 | Rockford Fosgate Punch 401S Car Audio...

2 Answers

I have a thunder 5604 and all of the suden the short light came on and stop working, i disconect it and , put it back but th light still on an no sound. it doesnt smell like burn, im a mechanic and...


theres a few possible issues pull and replace all of the fuses also use atleast 4 ga power and ground wires if ur ga is 6 or up get a new amp kit i know my protect mode goes on when the ground isnt connected if none of that works take it to the company you got it from and have them check out the internals

Jun 17, 2009 | MTX Thunder5601 300W x 1 Car Amp Mono...

1 Answer

Trying to find the right FET to replace burnt up ones with


hafler use international rectifier hexfets. there is alot of confusion what constitutes a mosfet amplifier.
if the outputs are mosfets instead of bipolar transistors, it is a mosfet amp.
some designs are using mosfets to drive the switch mode power supply,but use bipolar output transistors.that is not a true mosfet amp.
you need to go to an electronic supplier for the repair industry.
or the manufacturers warranty depot,who will be able to order them.mosfets are very high current devices,you have to ask ...why did they fail. if they are the switch mode drivers,there is bad capacitors in that circuit

May 23, 2009 | MTX Thunder 5-Channel Amplifier 895 Car...

1 Answer

Apx stopped working, MTX 702x


maybe the audio amplifiers Ic´s damaged or the power fet

Mar 06, 2009 | MTX X Thunder 702X Car Audio Amplifier

2 Answers

800.2


With your multimeter set to DC volts, the black meter lead on the ground terminal of the amp (not on the point where the ground wire connected to the vehicle) and the head unit on (so the amp will have remote voltage applied), touch the red lead alternately to the B+ and remote terminals of the amp. If the voltage is below ~11 volts, you need to check the wiring feeding whichever line is too low.

If the voltage is OK, the amp will likely need to be repaired. If that's the case, do you want to repair it yourself? This amp may not be easy to repair. If you are not interested in learning to do this type of work, you should pay to have it repaired. If you want to repair it yourself, I'll try to help you through it.

Nov 11, 2008 | Rockford Fosgate 800.2 Car Audio Amplifier

1 Answer

250/1 powers on but no output


If the amp is not going into protect, the power supply FETs have probably failed. In the corner of the amp near the toriodal transformer, there are 4 FETs against the heatsink. When these fail, the 47 ohm resistors at the base of the transistors often fail. If the resistors are dark, it generally means the FETs have failed. If you disconnect the amp from power and measure the resistance from leg 1 to leg 2 of the power supply FETs, a reading of near 0 ohms indicates the FETs have failed.

Nov 06, 2007 | Jl Audio 250/1 Car Audio Amplifier

Not finding what you are looking for?
MTX Thunder 81000D Car Audio Amplifier Logo

Related Topics:

302 people viewed this question

Ask a Question

Usually answered in minutes!

Top MTX Car Audio & Video Experts

Professor_V
Professor_V

Level 2 Expert

92 Answers

Matthew Spark
Matthew Spark

Level 3 Expert

1066 Answers

yadayada
yadayada

Level 3 Expert

75077 Answers

Are you a MTX Car Audio and Video Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...