Alpine 3552 drawing a lot of amps.

[Kennynva]

Hi everyone..new here...and dont want to just jump in..but know no other way.

I have a used Alpine 3552 that seems to be drawing a lot of amps...is there a way to start repairing this amp...or is it suppose to do so

It seems to be drawing around 15 amps at idle...with nothing connected to it..
Im connecting a wire from the battery + over to the top of the two pin connector that should go to the blue and white wire from the main cd player..

Is this ok to do this...just for a test that is.????
Im seeing on here alot of bad transistors on the power supply side..
There is NO burning of parts or the main board at all,, nothing burnt anywhere that I can see..at least on the top side..
Any thing will greatly help me out...

Thanks to all that respond..

Kenny

 

[Perry Babin]

What leads you to believe that the PS FETs have failed?

What's the history on the amp? Were you using it and it just quit?

Have you checked the output transistors?

 

[Kennynva]

Well I have no history on this amp...the D1669 s are getting to the point of smoking...in about 15 seconds of tuning it on..so I cut all of them out...seems there are 6 of them and two c3852 s....and it dont draw any amps now..
I did it one by one...and it made no difference removing each one at a time...the next one will still get hot...and now that they are removed there is no heat anywhere...or no burning smell of any kind..
The green light is still on after they were all removed..

The only reason I thought they were bad was they were heating up way to fast...

What I did was number each one...when I remove it..left to right 1 thru 8.

Before I did this...I removed all power...used a multimeter on continuity, and all of them showed a direct short to ground..on the 3 legs...so I knew that wasn't right..
I do know some electronics...but this seems a little hard for me

So what do you think???? oh and they were making a fast oscillating sound too..

So if I did right ...and they are bad..where do I get these,,,from what Ive read here..they seem hard to find..

Oh how do you check these since I have them removed from the amp??

Thanks for all your help

Kenny

 

[Perry Babin]

They could have been heating up because the transformer is shorted or the outputs are shorted.

I don't know if this amp has the riser plates but if it does, you remove those and leave the transistors clamped to them to prevent them from overheating.

Getting exact replacements may be difficult.

Use the bipolar section on the following page and post the readings for the 1669s. If they all read about the same, you only need to post for one transistor.

 

[Kennynva]

Hi,,thanks for the info...here are the photos of the inside..It has plates that are above the rest of the top of the amp..if that is what you mean by risers then yes is has them..

I am more of a laptop computer repair person..but know alot about electronics..

Thanks for the info...there are two (fets I guess) that have numbers of C3852 and I have checked Google and it says they are "pillows" I have no idea what that is..
If the transformer was shorted would the light change from orange to green on the front of the amp...? or would it blow the fuse.
I cut all the d1669 s out and it dont draw the amps it did before I did it..I let it stay on for an hour with no heat and no sounds...
I found the d1669 s on some Chinese site for about 80 cent each if I buy 10..with free shipping..it just will take a month to get them, which it take 8 anyway...
I guess I cant upload a file..it say a "security token.." something or other..has happened..
Kenny

 

[Perry Babin]

There are few far east sellers who are selling legitimate parts. The ones that are long discontinued are almost always counterfeit.

None of the transistors you listed are FETs. They're bipolar junction transistors (BJTs or simply 'transistors'. 'Pillow' sounds like a bad translation.

Cutting those transistors out removed the part of the circuit that generates the pulses to drive the transformer. It's about the same as pulling the fuses.

 

[Kennynva]

OIC....so how do I test these parts...I seen something on youtube that says to select diode on your mulimeter...then hold the - or ground on the far right side...first...then touch the red + on the center leg...should be no reading..but it should "charge up" the capacitor then move the red lead to the left side and it should read something...then when it discharges after a second, it will "switch" back and have no reading..

Is this right???


Thanks for all your help Kenny

 

[Perry Babin]

Checking bipolar transistors is covered on the basic amp repair page (link in sig line below).

 

[mikep28]

you need to just purchase perry's disc from his site.. It covers things Id not figure out for weeks... I spent my early years doing 6800 cpu and 6821 pia multi processing unit repairs in pinball machines. Im well versed in circuit design but knew nothing really about amplifier design.... Bought his tutorial and read it... Mean read it and Im fixing stuff... Best $50 you've ever spent...

 

[Kennynva]

Well this is what I just did...I got to thinking about the output PNP transistors...so I removed the motherboard..flipped it over..and it seems like the output transistors has gotten hot at one time...not burning the board but hot, I can just tell..so I checked each one out...there are eight of them..A1671...and C4386 which i found out are the same thing...now 6 "tested" continuity, to me fine.as in no continuity but in certain ways..two next to each other, no matter which way I tested it..the E B C had full short continuity, the rest didn't, so in my opinion they should all read the same
So I remove them two...then I re-installed one of the other D1669 ..which got so hot in 8 seconds you couldn't touch it...and it was not getting hot any more...and the amp draw was around 2-3 amps...idle...
My next step is to re-install all the D1669 s...then try it..
Could this be the whole problem???

Thanks Kenny

 

[Perry Babin]

Yes. Shorted output transistors could have caused the PS transistors to overheat.

 

[Kennynva]

s...Hi thanks for the info...Is it safe as a test to run this amp WITHOUT the two power transistors???? as a test...in other words ,, I'm going to re-install the D1669 s.....and hook it back up... and see if I wasted my time removing them...

Will it output anything with the two missing...???

Will it hurt anything to run a test without the two???

I have also learned that the smaller transistors in between the output transistors are for temperature monitoring..to keep the output transistors from overheating..and to balance the output..current I think..

I tested the power sides controller IC the PS494C from NEC, I believe..and got all the right voltages out of the pins. I checked it the same way you would check the TL594 chip in the article you showed me..

Now where would I get these output tranys..

Thanks Kenny

 

[Kennynva]

Well I went on and fired it up....and guess what...all three channels WORKED...got sound...out of all ...I checked all the switches in all positions and the variable gain worked and fixed worked...far as I can see it..all of it works except the one channel..

Whats the wattage output on this amp...?????

So I learned alot...but the number one thing I learnd is NEVER JUMP ...but sometimes you just have to...

IF i would have left all of the power supply transistors soldered and did a check on the output transistors it would have saved alot of time..but hey..all I have it time...so the site you referred me to really helped me alot..

Does anyone know when this amp was made...Alpine 3552, just an approximate date...
Kenny

 

[Perry Babin]

3 of the 4 channels should work with the missing transistors.

It shouldn't cause any problems having the missing transistors but be careful and be prepared to disconnect the amp if there is a problem.

The transistors between the output transistors are likely for bias compensation. Alpine did use transistors for temp monitoring but those were all clipped to the face of the transistors if I'm not mistaken.

I don't have a source for the outputs. If you find them, they're likely to be counterfeit, especially if they are from the Far East. I would try a different transistor if you cannot source them from a reputable distributor. The FJA4213 and FJA4313 may work but you would need to use an insulator and may need a longer screw.

 

[Perry Babin]

It was likely made in 89 or 90. You can look up the date codes on the various parts to see when they were made.

 

[Kennynva]

That was the next question...on the bad or burnt parts..there were 93 94 numbers at the bottom, below the part number..

Maybe that is a date code..

Kenny

 

[Kennynva]

Here are the bad parts..

Can you mix part numbers for these...I know you probley shouldn't...maybe on each channel use the same part number..but can mix different numbers on different channels..does this make since???

Got it all back together except these two parts..ran it for an hour...it draws around 3-4 amps..idle, with no input...just the gains almost all the way up..

Kenny

 

[Perry Babin]

You need to find an IC or transistor that you can find the datasheet for that shows the date code scheme. The simplest was 4 numbers. The first two were the year, the second two were the week.

 

[Kennynva]

Here is what it looked like before I started..
The bottom transistors, the 3rd and 4th from the bottom left...are the one's that are bad..

Kenny

 

[Kennynva]

Do all amps or just Alpine use the 8 power supply transistors...???
Now Im on the hunt for the parts...

I seen somewhere where this was or is a 75 watt a channel x 4 amp...
This is just a question here..not thinking of doing this..

But what would happen if you put larger power out transistors??? Im sure you would need the power supply to provide enough power, or amps to drive them, and Im sure there is a limit...but I would think you could go from a 40 watt, to a 50 or 60 watt, without burning something up....

Kenny