Question about MTX Thunder502 Car Audio Amplifier

1 Answer

Gain pots are shot

I can't find the values for the gain pots on my amp. I need these so I can find replacement pots and get it working again. any help?

Posted by on

Ad

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that got 5 achievements.

    Novelist:

    An expert who has written 50 answers of more than 400 characters.

    Champion:

    An expert who has answered 200 questions.

  • Expert
  • 219 Answers

If you have the old pots then the value is usually printed on the side of the pot. If there is no number and you have the pot then you can open them up and using a ohm meter take a reading directly off of the carbon film of the pot. Read from one end to the other. I would expect something on the order of 25K (K=thousand) to about 50K. If you can , get the audio taper style of pot, but in a pinch the linear taper will work. The trickiest part will be to get one that is close enough in size and shape to directly replace the original mounting. Good luck. By the way, in extreme cases I've even used fixed resistors (3 or 6 resistors depending on mono or stereo) to replace a pot and then you just choose resistors that will place the volumn at say 2/3 full.

Posted on Jun 30, 2007

Ad

1 Suggested Answer

Anonymous

SOURCE:

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this 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.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Playing bar chord at A 5th fret fine move to 7th fret amp gets loud and pops. normal gain at 3 to 4 volume dwn wont do it


Sorry I remember now this is a solid state amplifier,
try electronics spray contact cleaner in the pots of the amp, you will need to unplug and remove the chassis of the amp to do this, there are little notches on the pots, that's where you want to spray, and work the nob back and forth completely, do this to all volume, treb, bass, etc... I know this will fix your problem because I have done this about 100 times servicing amplifiers, the way a solid state circuit works if the pots are dirty the circuit doesn't complete properly causing volume issues, really hope this helps?

Mar 04, 2015 | AMP Music

1 Answer

Crate vc5115


Pots are essentially variable resistances and should have the Ohms value in it, and yes, you can stick one of the same value and amp should work like a champ.

Oct 04, 2013 | Audio Players & Recorders

1 Answer

I open my CS900 Peavey power Amp to service. This is when I realised that One Gain Pot is B50K and one is C100K. Is this normal or has it been changed ? the Two Gain Pot looks like it is not the Original...


Firstly, the two kinds of currently available pots are A and B, these are logarithmic (A) and linear (B) in their function.

Older pots were marked differently though, it used to be that linear was marked A, and logarithmic marked C.

A gain control should use a logarithmic control ( A, in the new coding system, or C in the older system ) so there's nothing wrong here.

As for the value to use, I would suggest replacing with 100K, the same value as the pot marked with the C, as this is an older marking code this pot was probably in the circuit originally and the 50K pot marked with the A probably found it's way in there in the more recent past.

I hope this helps

Apr 05, 2011 | Audio Players & Recorders

1 Answer

The balance pot of my NAD C370 is not working, will the amp still work if I remove the balance pot?


Only if you replace the pot with two resistors of equal value. Both need to be also equal to 1/2 the value of the pot. Then at the point the 2 res tie together -- Tie that point to the middle lead location and the other leads to the other points where the pot was connected. Use 1/2 watt or 1 watt res.

Nov 02, 2010 | NAD C370 2-Channel Amplifier

1 Answer

Behringer's Ultrabass BXL3000 Gain knob broken


You need to replace the potentiometer with the broken shaft. You can open the unit and try to get a part number or go to Behringer parts to get an exact replacement. The pot must be matched for value, taper, and mounting and shaft dimensions.

May 23, 2010 | Behringer Ultrabass Bxl3000

1 Answer

The gain control no longer works on the clean/crunch channel. all other features work fine, whats wrong with my amp?


Hi there. Try re-soldering the control pot to circuit board connections. If not, use ohm meter to verify pot functionality. If bad, replace.
Thanks
Paul

Jul 10, 2009 | Marshall Mg100dfx 100-Watt Combo Guitar...

1 Answer

I need to know the value pots to buy for vol,bass


If you have the old pots look on the edge of the cans (metal backs) for the code. Take them to a good electronics supplier and they can match them or measure the resistance from each outside pin with all pins free of interconnection. You will also need to know the audio tapers. The supplier should be able to tell from the codes.

Jul 08, 2009 | Music

4 Answers

Gain knob produced crackling sound


This is usually caused by oxidation in the potentiometer (fancy name for your volume control, also called a pot). The solution is to buy a small spray can of tuner cleaner, then unplug the amp and partially extract the electronics chassis from the case -- usually by removing screws in the top (but NOT usually the top handle screws), then gently sliding the chassis forward until you can easily see and reach behind your gain knob. You should see a squashed metal cylinder attached thru the faceplate to that knob -- that's the pot. It will probably have 3 wires attached -- don't worry: these never have voltages high enough to feel even when the amp is on. Either near where these wires are attached or elsewhere on that cylinder there should be one or more small holes. Using the small plastic tube that came with that spray can of tuner cleaner, spray a small amount of cleaner into the pot, then turn the gain knob from maximum to minimum and back several times. I usually do this by plugging the amp into a receptacle and moving the knob this way BEFORE using the spray, listening for the noises, then I spray it, manipulate the knob as described and hear the noise disappear. Unless you're confident about doing that, DON'T! Instead, slide the chassis back into the case and plug the amp in, then see if the noise is gone. If so, put in all the screws and you're done. If there's a noticeable improvement, but still some noise, move the knob bank and forth a few more times to see if that fixes it; if not, unplug the amp, slide the chassis out again and repeat the spraying procedure one time, then reassemble the amp and plug it in. If your problem is still not gone, you'll have to replace the pot. If you know how to solder WELL, you can order another volume pot thru a Marshall dealer or online, OR you can remove the pot and take it to a local electronics store where they can probably find an equivalent potentiometer at a lower price than the genuine Marshall part -- be sure to ask for one with "an audio taper" (a logarithmic change in resistance that corresponds to how audio amplifiers control sound). Good luck, and please post your results on this website.

Jul 08, 2009 | Marshall Mg100dfx 100-Watt Combo Guitar...

1 Answer

Gain conrol problems


relatively simple 2 leg pot. fix.
Under $50 to repair.

Thanks for using FixYa - a FixYa rating is appreciated for answering your FREE question.

May 03, 2009 | Jl Audio 500/1 Car Audio Amplifier

Not finding what you are looking for?
MTX Thunder502 Car Audio Amplifier Logo

Related Topics:

79 people viewed this question

Ask a Question

Usually answered in minutes!

Top MTX Car Audio & Video Experts

Professor_V
Professor_V

Level 2 Expert

93 Answers

Pierre Laplante

Level 3 Expert

2042 Answers

Marvin
Marvin

Level 3 Expert

85223 Answers

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

Answer questions

Manuals & User Guides

Loading...