Response Precision car amp repair
Вставка
- Опубліковано 14 жов 2024
- Repair of a car audio amp that won't make sound.
Tools I use -
Soldering
Quick 861DW hot air station
Duratech TS-1640 solder iron
Multimeter
RMM760D - can be found under many name badges
Microscope
Luzky Zoom 3.5 - 90x simul-focus single boom stand trinocular stereo microscope
Camera - Lucky Zoom HD 14MP
Oscilloscopes
Siglent SDS 1102CML 100MHz 2CH
Philips PM 3305 35MHz 2CH
Bench supply
Powertech MP-3086 0-30V 3A
I would have to say that 90 % of the amps I have repaired, the output transistors...were shorted...and now I check them first...good video...
I installed a transistor and it keeps blowing?
TO-22 diodes are verry common in duals as bridge rectifiers nowadays, and the SMD circuitry can be pretty tricky if you dont have the right equipment, hardly anything that I have had come across my bench as used the through hole.
As far as replacing all of the fets and bad parts while you are at it, this amp will be back on the bench within 6 months and the owner will learn their lesson.
FYI, Amazon has Uxcell Pair 2SB688 + 2SD718 8A 200V Silicon Power Transistors at a good price.
This video was posted so long ago i dont really expect an answer but anything helps. Is that any specific type of sil pad you used for re assembly? I have an amp i have to remove everything to repace the rcas, its just reassembling everything were i dont know what the mosfets use. Mines seem to be in a similar material to the one that these were prior to removal. Thanks in advanced
I've always re-used the old ones, never been a problem. As long as they aren't torn in a way that would allow the metal tab of the transistor to touch the chassis. If you had to get new ones, just go for the same thickness. I usually put a little thermal paste on each side to.
My amp started making a heartbeat type thump. I know its the amp because I replaced it and new amp is fine. My old amp has similar parts as this one. B688 and D718 on the output side. The amp worked just would have heart beat thump on the subs when at low volume. If you cracked the volume way up it would sometimes snap out of it for a second but then start back again. It's a Jensen XA2250. Cheap amp so no biggie. Output FETs test good and are not shorted. Only thing suspect is one of the power MOSFETs IRFZ44A shows a dead short between D and G but only when switched on. It turns on and off it just shows no resistance on the supply and drain when on. The other one shows 170 to 180 on my MM on diode mode. Not sure if this could've been causing the thump or not.
I had that wrong. The IRFZ44A MOSFET shows no resistance when switch on between D and S but it does switch on and off. The other IRFZ44A's show resistance of anywhere from 30 all the way to 170 to 180 on my MM through D and S pins when switched on. That seems like a big difference from the one that reads a steady 001 when turned on so I'm wondering if that could be my issue.
Hmmm.... measuring across pins with voltage on them will upset your meter in resistance mode and the reading would be meaningless. If there is enough voltage on the gate to turn it on you should have same voltage on D as S. If it's in the primary side then it will be being switched rapidly so a scope might be better to see what's happening. Check secondary side voltage on the output capacitor isn't fluctuating. The heartbeat sound could be a result of power supply repeatedly starting up then shutting down. There might be a feedback issue where it doesn't know what the output voltage is, or there could be an overload on the output. Make sure secondary capacitor is discharged and check resistance across it isn't low.
Ryan96se I got a question what is the name of the party and where I can buy it
Very good video! Keep up the great work. I am working on an amp that the green light comes on with no audio. I suspect an op amp on the input. Any recommendations on troubleshooting the input side of the amp? Do you have any videos for that?
Thanks! You should be able to find the input and output pins of the opamp from the datasheet and if you have a scope see if you have signal going in and signal coming out. If not in look further toward the audio input. If not out make sure opamp has valid power rails and if so my guess is replace opamp.
Mostly the output transistors. One or more of the The big ones should be shorted. I fix them everyday.
Hey, im just wondering what sort of chip runs the error amplifier for the protection mode?
Brilliant!
Do you fix amps? I have 2 that need fixed
what would cause my rockford fosgate punch 250.2 to put out a steady dc voltage when the remote wire is connected thanks in advance
I have a magnat rx44 4channel amps which gives a buzzing sound from the second channel i tried to grund the earth of the rca to the ground but the buzzing noise didnt go away. Tested with another 4 channel amp from my friend and the buzzing sound was gone, tested with severwl different rca cables and configs awsell.
+KosovarMods I wonder if some power supply capacitors have failed and are letting switching noise through from the power supply. Also, check for bad solder joints.
Hey, nice video. I have an amplifier that turns on green. But no sound. What should I check. Or what part should I focus on ? I have no idea. Tried several different speakers but none work. So I think the problem is inside the amplifier
If you are positive your source is putting out a signal into the amp I'd probably jump straight into testing the output transistors like I do at 16:50. Blown ones don't always cause a fault light. If they test ok you'll likely need to get hold of a scope and trace the audio through to find out where it's stopping. Find the user manual for the amp and make sure it doesn't need something like a cable between 2 sets of RCA sockets (if it has more than one pair) to make sure there's not some kind of split off to run multiple amps or something and the signal is going in then out but not back in to the main amp. Give the high and low pass filter switches a toggle to make sure they aren't dodgy.
I got a amp the “slave” switch broke off and no i cant get any sound but sum loud thumps wehm i poke and prod around in it . no protect light no smells , i soldered the slave prongs together at the max number idk exactly what it is ) yesterday and got sound out i only had it quick rigg running off another amp to test if my fix worked tho but it sounded like ut was playing all the frequencies not the lows i want and my rcas only wanted to work in my invert jack connectors i know i usually have them in the low in connectors but they didnt produce any sound idk now what this sound like to you ?
Nicely done Sir.
Awesome job.
Cheers mate!
I replaced a broken MOSFET and it's neighbor, just to ensure matching behavior on that side (my modest amp only has 2 on that side). The amp now works well and sounds perfect but will not turn off. The remote wire/switch/feature is completely ignored. How can I regain that functionality? What else should be checked?
Good job! Follow the circuit from the REM connector. It will likely go to a transistor then possibly to the switching controller for the power supply. I once had this transistor shorted which had the same effect.
hi . my mono amplifier stop work. the ligth turn on but dont have sound.. just make like very low sound. please you can tell me couple reason and tips what you tinks its. maybe the amp in a moment the positive and ground cable touch toggether but i dont have sure..
If the speaker wires touched while it was running then check the ouput transistors as I did in this video.
Dear sir i have rockmars 3000watt car amplifire when I give battery current its on for a second immediately its p55nf06 transistor dead I replaced that transistor but same process again all output transistor are ok
Not sure what problem might be without seeing it, or a schematic.
Jonny Fix sir how can i show you and contact with you i m far away from you so kindly help me
My Alpine amp has started to create a constant rumble in my subs even while only connected to a 12v battery and the subs. It still works and plays music, but continues to rumble when it has not audio signal. I opened the amp to inspect it, and everything appears to be in order, no bulging caps or cracked fets. It has a .3v output on the wires going to the subs. Any ideas what it could be?
I don't sorry. Some oscillation being induced somehwere. Would need to trace it through with a scope to see where it was coming from.
Jon Luke bad ground in your deck ground it to your cig lighter
It was wired directly to the battery in my trunk. I ended buying a more powerful Kenwood and thay fixed the problem
Ask something sir about my legacy la790 it turns on green but the speaker sounds low it's something wrong the outputs transistor or any component in the amp is bud?
Try another speaker to rule that out. Make sure you know the input signal isn't low. If it's not distorted and the gain controls are set to max and it's wired correctly then you will need to fault find the input circuit and whatever preamp stage it has.
Last question sir Jon I try put power.. it's is working or not but problem is burn my speaker on left channel and i try to remove it on supply of the left channel and give it power to the right channel it's working..do you have idia sir what wrong on the left channel maybe the output transistor or supply? Please...sir cuz I want to fix my old legacy amp. thanks sir..
@@edgarfollosco4143 It's quite possibly output transistors. Make some measurements as I do here at 15:15 using diode mode on the meter, it should be obvious if they are bad. You may have to unsolder at least the 2 outer legs to be sure of the reading.
where do i find to220 common anode package diodes to buy. i cant find diodes that are for negative side or diodes going out of middle pin. please help me find ultra fast diodes with at least 20a per diode i have spent 10 hours looking for it everywhere. i can only find opposite from what i need. my radioshacks wont have it. pleaseeeeeeeee
What are the numbers on them?
Let me guess there isn't any? What kind of amp is it!
My 2150 hct analog meters move but no sound. I know it needs 3 fets. Ya think any transistors
The analogue meters might be driven from the pre-amp section so a fault in the main amp will cause no sound. You would need to test the components to find out what has failed.
@@JonnyFix what do I check
@@kevinhancock7166 Start with the main output transistors like I check at 17:15 here.
Red light Green light one two three!!!
My amp turns on and everything just like normal but you can barley here anything you can here bad but barley then you hear like a buzz and before this Happened the amp over heated and made like a poping noise and I think it heated up bc it's a 1 ohm stable and I connected the subs wrong and for your info it's a Memphis mojo mcd4k yeah it's a badass amp but it doesn't play I want to get it fixed the cheapest way possible and at the moment I'm using another one exactly the same since I have 2 of those amps thank god
+Carlos Soriano Probably burned out the output transistors, these are the most common things to fail when speakers are connected wrong. If the pop came from the amp you will probably find exploded parts inside, look for black smoke marks, you might have to lift heat sink clamps. Replace these and see where you're at. If you don't have test equipment, replace all output transistors to be safe and see where you're at. They don't always show physical damage when they fail. Might set you back $10-15 each, can't find much info on this amp so I'll assume there will be at least 4 per channel. There may be other damage but it's a start.
+Jonny Fix thank you for replying friend and I did open it and I do see black marks in the back of where they blown up and the amp is a Memphis mcd4k it's the older model but it sounds super loud and where are you located? Because I would fix it but I'm not so familiar with this stuff if we live close I could meet you and I'll pay you to fix it for if you could if not then I have no choice but to sent it to where it was made from :/
+Carlos Soriano I'm in New Zealand and not currently accepting viewer repairs. Sorry, and good luck, hope you get it sorted!
i have amp with protection mode
how to repaire
Same my problem
what would cause the amplifier to come on but then goes off
Can you hear sound out speaker before going off? Does the protection light come on? Does the power light come on but go off shortly after and no sound?
To all that are asking me for: I will reply I have been very busy. I will try to answer you all please be patient. I want to thank you all for your responses.
Where are you located ?
New Zealand
don't buy Toshiba replacements from Cheng Chen ,China. I bought 24 replacements and they were no good,can't say counterfeit because they worked until you drove them above nominal volume.,so after shorting out over half of them I physically cut one open and compared it to an original I was replacing and the junction area was a fourth of the size, never order from over seas.
+Scott Miller you get what you pay for
+JusstyteN over 100$
Scott Miller 100$ for what?
+JusstyteN 24 crap Toshiba nock offs. now I use Georgia audio lab, he is awesome.
Scott Miller do you know where to buy common anode or common catchode diodes with to220 package?
good video............... enda enda umhhh enda enda so umm enda umm lol
no light on car power amplifier no current to out put transistors
you get what you pay for
i am agri full all car amplr trinig
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