PPI amp (power precision) blew out

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-i just hook up this lil system in my car and driving it down several days after and the sounds cut off.

-i believe i bridge the amp wrong, i prolly mistaking w/ the left/right vs white/red from HUnit to the amp.

-just open the amp and one of the semiconductor has burnt. its black rubber and has double end conductor to the board. the board label it (the semiconductor) TS1.

where can i find this TS1? can someone specify what this semi is is its category?
 
PPI amp.

Hi, I think what you are looking at is the Thermal Sensor. This is the designation TS1. This is a special fuse that is supposed to open up when a preset temperature is reached. There is not normally a lot of current passed through those so I find it odd that it would burn. If it is burnt, I would think there is a lot more damage to the amp then just that piece. Did you loose the ground connection on the amp? That might cause a problem like that. Regards, Steve
 
thanks for the reply. i thot about grounding too. iwill try to remount the ground at a solid spot.

since its a thermal preset protector or whatever it is, can i replace it w/ a fuse to test if the amp still work?

btw, all of the other semi doesnt seem to affected to the naked eye ...... could it fool ones eye?

btw, i tried to look for that piece on www.mouser.com but there are so much thermal sensor. can someone help me find it? i am not familiar w/ semiconductors.
 
Do you have a DMM? You can measure the switchers to see if they are blown. Measure from the tab to pins 1 and 3 and across 1 and 3. If it is short, then the part(s) is bad. The amp will fuction without that thermal sensor, and if it does, then you know you have no other problems. What amp do you have? I have just about all the schematics for the Power Class series. I have a dead PC amp that I will crack open later to see if there is a part number on the TS's.
 
Precision Power (PPI, www.DEI.com is the maker)
Mosfet Power Series
PPI-2150M 2x150wrms
300W @ .02%THD
40HM load -12V DC

those are the info i can get on that amp.

btw, the theral sensor (ithink) has no continunity so its fried. the thermal sensor is not a tab-looking or square looking, its a symmetrical tubular structure that looks like a regular resistor but black rubber.

when to think of it what you said, its fried.

any chances?

just to let you know, i have no knowledge of how to build an amp like yall guys. if yall can take me though this w/o givin urself a headache would be much appreciated. the thing that i am only good at is using my DMM to test circuits.
 
OUCH!!!!! That thing is old!!! When I worked at PPI, I had to fix a couple of those things. A PITA!!!! The thermal sensor should not measure low, so it may still be good. Unless it looks visually cracked. Like I said above, measure the switchers, the MosFETs in the power supply, to see if any of those devices are shorted.
 
hey am prolly gonna waste ur time but since my hands are somewhat wet, i want to mess w/ the amp to see if i can learn seomthing. so if i can take a pic of the board, can you pin point out what to test w/?

again, i honestly do not know how to test mosfet or relation to transistor, nor switches. what exactly are switches? when you say switches, the only things that comes to mind is relay, but still puzzled.

anything is koo w/ me.

thanks for your times and others here.
 
Switchers are what we call the MosFETs in power supplies. When a DC voltage is applied to a transformer, there is a spike of current that occurs, and it induces a voltage in the secondary windings. This is, pretty much, an instantaneous pulse of current and only provides a pulse of power to the secondary. So the 12V, that our automotive electrical system supplies, is worthless as it is. Transformers are used to step-up, or step-down voltage, but they can only work with alternatiing current. With AC, an electromagnetic field induces the secondary wingings with a current. Because of the DC resistance of the coils of wire in each, the primary and secondary, a voltage must occur across each side of the coils. If the secondary has more windings than the primary, then the voltage is stepped-up and if the secondary has less widings, than the voltage is stepped down.
Since the DC voltage of the car system is not really useful for an amplifier, we need to convert this to alternating current, so it can be stepped-up. The 'switchers' are MosFETs that are used to open and close the path of current to ground. So one side is, basically, connected to the battery(+12V), and the other side is connected to ground, through the primary winding of the transformer.
Now we have a IC called a PWM(pulse-width modulator), that chops the DC voltage to a certain duty-cycle(also abbrv. DC) and is connected to the gates of the 'switchers'. This PWM chip is used to turn the MosFETs on and off. This creates AC so the transformer can step-up the voltage to the secondaries.

It's late and it is time for bed. Hopefully this will give you a little insight as to how a switching power supply works.
 
not really quite understanding what switchers are, but can you explain the actual pin of the switcher(mosFET) and what it does, maybe i can understand it better.

how could i test it? does it need to be desolder? in the mean time ill search the net on more of this mosFET.

is there an analogy to this mosFET chip or a break down of components thats built into this one chip?

BTW, what is the simpliest amp called? maybe i can learn from the simpliest amp and move up to understand whats goin inside the chip.

iono if you taken circuits in college or whatever, do you learn in stuff also? i havent taken the course yet but have to soon.
 
The MosFets are TO-220 devices that are mounted on the heatsink. They are called 'switchers' because all they do is turn on and off. Pin 1 is usually the gate and pin 2 is the drain and pin 3 is the source. I stated, up above, the easiest way to test these devices. The SG3525A, is a common PWM chip that is used in many switching power supplies, here is a link: http://rocky.digikey.com/WebLib/On-Semi/Web Data/SG3525A-D.pdf

My computer is being a piece of chit right now and won't let me operated my scanner. I need to reformat my drive and reinstall everything, then I should be able to scan some schematics that will help you visualize what's going on in the switching power suppies.
I'll post more after I fix by f'ing computer.
 
Here is a schematic showing a simple switching power supply. Q1,2 are the switchers in the schematic. Notice that the output pins of U3(pins 11 & 14) are conneted to the gate of the mosfets through R4 and R6. Also, notice that B+ is connected directly to the transfomer, and is grounded through the switchers.
 

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TO-3...if you may be so kind...

When did you work for PPI and what did you do for them? I know the old Art series quite well - especially the overabundance of silicone thermal goop they used at the time. :rolleyes:

Do you have the schematics to the A600 Amp? I've got one that has quite a few eroded traces from a little marine trip its former owner went on. I'd like to know where they go. Please let me know at:

envisionelec(at)earthlink(dot)net

Thanks,
Aaron
 
Here is a schematic for a higher-power power supply. Notice the parallel switchers as well as the push-pull drivers used to increase the current supply to the gates. Also, this is a regulated power supply, unlike the one I posted earlier.
 

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TO-3 said:
OUCH!!!!! That thing is old!!! When I worked at PPI, I had to fix a couple of those things. A PITA!!!! The thermal sensor should not measure low, so it may still be good. Unless it looks visually cracked. Like I said above, measure the switchers, the MosFETs in the power supply, to see if any of those devices are shorted.


TO-3,
Back in 1998, I heard that the PPI Powerclass Series was designed by some Ex-Krell engineers. Is that true? Cause I was suckered into buying a PC-2350 powering my woofers and a PC-450 bridged powering my highs. I just love those amps....

Are they as good as I think they are or not?

thanks in advance!!

K-
 
K-amps said:



TO-3,
Back in 1998, I heard that the PPI Powerclass Series was designed by some Ex-Krell engineers. Is that true? Cause I was suckered into buying a PC-2350 powering my woofers and a PC-450 bridged powering my highs. I just love those amps....

Are they as good as I think they are or not?

thanks in advance!!

K-

Mr. Eichenbaum was the engineer that was from Krell, and ended up going back to Krell. As far as I know, he only designed the PPI-2500F1 and the PPI Tube Drivers' audio sections. I don't believe that he did any designs for the Power Class. The PC series is the same architecture as the Art Series, only with different chassis. The engineer that designed the PC amps originally designed the Xtant amps, left to work at PPI, then left to work for JL Audio.
 
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