Is this amp finished? PICS of the inside. Please Help

[akheathen Premium Member]

first, use a headlight, or resistors to limit the current when you power it up. next, use a battery to take care of the voltage drops, and smooth out the power some. what is happening, is that the amp is trying to power up, but the charger voltage is dropping too low for it do operate, so the power supply shuts of, and then activates again when the voltage is back above about 10. really, the idle current alone on this amp should be 2-3amps, and turn-on spike is probably anywhere from 5-15a, depending how far the voltage drops. have you alrady ohmed the legs on all the output and ps transitors?

o.p.- you can order from digikey, and they have all the info sheets, etc with them. the bottom numbers are the build code/date, which will show on the spec pdf. something like 35 p = year/month week, or month/year line, or similar combinations. what you will find is that the digikey, and other part numbers will have more preffix/suffix and different variations. look at the manufacturer part number. current available parts are pretty much going to have a pbf, or something on them that indicates "lead-free", which you will see on the list if you pay attention. stick to a good brand, if not the same. those would be 2stc4467 and 2st1694 in st micro parts. you can check mouser, etc, but just googling will get you a list of suppliers. the parts are becoming obsolete, but there are some replacement parts for them, i think mouser has a cross-reference.

 

[Extreme1ont]

mouser is where i ordered parts for my pioneer, i know its a crap amp lol its supposed to be more rms power then my 60rms x 4 old rockford i have but the rockford will out power it any day.

It was a starting point to see if i could make it work, the parts were under 15 bucks with shipping, parts for a 125.2 punch i have is going to be around $50, i didnt want to spend alot if i wasnt able to repair it...

The Kenwood is a friends. i even hooked it up in my own car that is a current working system to test it and still does the same thing it did in my friends truck..

Volume level cranked right down, turn it on and after 10 seconds tops the amp would shut off and fan keeps going. he said it was working good and he pulled it out for a day and put back in because he needed the back seat, hasnt worked since its been back in.

The kenwood has a few transistors with markings and ->

 

[bubbagumper6 5,000+ posts]

Good sites for parts:

Electronic Components Distributor | DigiKey Corp. | US Home Page

Mouser Electronics - Electronic Component Distributor

US - Electronic Components Distributor | Newark.com

Electronic Components from the Best - Future Electronics

Allied Electronics

 

[Extreme1ont]

i just done more testing, i believe all the power supply fets are fine, they all test with the same numbers, none are higher or lower or no resistance, they are all the exact same reading..

So i move over to the out put side, and i find on 1 channel the transistors are reading low..

C4467- 010

C4467 - 001

A1694 - 227

A1694 - 227 with these removed they are reading 500-505 the 2 on the other side are 512 connect to the board, im assuming these are ok to re use.

now on the other side of the board..

C4467 -785

C4467 - 786

A1694 - 512

A1964 - 512

Not sure what setting that is on the multi meter i think its straight resistance for ohms. either or... i can still see the one side on the output has a problem.. its not totally shorted i guess so its not popping fuses.

The pioneer amp i have has the exact same out put transistors, so im going to test them now and see if they will match up with the other side and swap them, used parts is probably not the best but its a quick fix to see if thats the problem and no wait time to order parts lol. i will probably never use the pioneer maybe only for selling it but going to cost more in parts then what its worth.

Edit... ones in the pioneer are different.. A1908. C5100. going to check data sheets, figured out why it stopped working too, has 3 blown power fets, guess i should have gotten the insulated ones so i could fasten them properly 16 week waiting time though from mouser because they are out of stock.

EDIT..... http://www.ebay.com/itm/2pairs-2SA1694-2SC4467-A1694-C4467-NEW-ORIGINAL-Sanken-/170664641408?pt=LH_DefaultDomain_0&hash=item27bc67c380

EDIT again lol.........

figured it out.. pretty simple.. output transistors BAD.. the C4467 chips on one side only are bad, the A1694 test good when they are removed separate, the C4467's are bad so was giving false readings since its on the same circuit.

I removed the C and A chips on the left output and the amp turns on and works on right channel.

So to the person that first started this topic, i suggest removing the output transistors and remove them to test and you will most likely find your problem. if its blowing fuses soon as you connect power then its in the power supply fets, if it powers on and the light goes out after a few seconds and fan stays running then its most likely the output transistors.

Hope this helps. Im a newbie to this.. this is the 2nd amplifier i tore apart and tampered with and i was able to figure out the problem.. so its pretty simple once you know what to look for.

the output transistors are the ones marked A1694 C4467. the smaller ones between are nothing to worry about, they detect heat and shut the amp down if it gets too hot, definatly ohm out the transistors though you will probably find your problem there.. if it pops fuses then you have other issue in the power supply part and in that case check the black chips closer to the side where the power connects. If one chip is bad you will get bad readings on all of them so its best to remove them from the board then check them..

video of it working.... ignore the crappy sound lol.. this is hooked to my satellite receiver output so its not very much power.



I need to find 2 parts for my old rockford amp, i have a couple and they mostly use the same parts having some trouble finding a couple...

U1620 and..

U1620R

They may look like the same part but im pretty possitive they are different, one chip says AKA other says KAK this is the polarity of the chip or something like that this is why i think they are different.. mouser doesnt have them and i talked to support they came up with a 863-MUR1620CTRG.. i dont know if i should get those and try it or find original parts...

EDIT^^^ these parts should be the same.. NTE6240 & NTE6244

Silicon Rectifier

Super Fast, Dual, Center Tap

 

[linearpower 10+ year member]

I would NEVER use a generic ECG/NTE part as a replacement device, there ARE NOT exact replacements. It is always better to use the parts that the factory used. Things such as the bias of the circuit can be miss-matched causing distortion or even failure of the amp again. MCM sells Asian transistors, as well as, PacParts.com is a online Kenwood part distributor, there is no reason you should have to use a substandard part to repair one of these units, when you can get the exact part. Just advice from a 25 year Authorized Kenwood Service Tech! Your factory part numbers are 2SA1694 and 2SC4467

The parts the other guy is describing in a Rockford amp are the negative and positive 1/2 wave bridge rectifiers, I have also repaired those for 25 years. Get those backwards in the circuit and be prepared to replace a lot more!!! These normall read a short between the outter legs and hardly ever go bad, possible that they could be bad but not probable.

They are 16 amp dual diode packages, one in negative arrangement and one in postive output arrangement. Parts that will work are FEN16CT and FEP16CT, but the root part number you are giving is a Motorola original part number, you just don't have the prefix and suffix of the root number.

 

[Chicago_one 10+ year member]

Long story short and a late update: I was working on this repair with Spooney, well he was pretty much diagnosing everything and guiding me from the sidelines. Hell of a guy to work with and gave me a ton of insight into amp repair.

As I said before, I am very new to audio repairs. Never soldered anything, let alone open up an amp and tested transistors, resistors, etc. BUT i picked up the sub/amp/box combo for a $35 steal and was determined to make it work.

So, as he helped me find out (and his first diagnosis), it had a couple shorted output transistors so we decided to replace the channel. Gave me a couple links to Mouser and the right parts I would need, I picked up a decent soldering iron and got into it. After a big delay with being busy at work, I finally got around to it this past week and tested it out yesterday. Solder came out pretty good, and was a breeze to work with. Also cleaned up all the flux.

Shorted Parts were:

2SA1694

2SC4467

Everything powered up on 10A fuses (just to be safe) with no problem. Switched it over to the appropriate 30A fuses, powered up, no issues. So I hooked up the sub and gave it a go.

It Works! Now I need to build a box that can better fit my trunk. lol

Thanks for all the insight and replies. I know this isn't a major system at all. But at $35, you can't beat the price. //content.invisioncic.com/y282845/emoticons/fro.gif.c695f1f814b01c4ad99fe7f8cccadd29.gif