I have two Car Amps. One is an Earthquake Powerhouse 2.5 and the other is a Pioneer GM-D500M. Both are blowing fuses without being hooked up speakers or source. I would like to repair them myself or at least learn some test procedures. Anybody like to help?
Thanks
Joe
Thanks
Joe
i'm sure you will get lot's of help on here,
first thing to do is rip one of them open and take some pic's and try and track down any components that look obviously burnt / blown to pieces and take pic's of them for us..
also do you know any info on how they failed? were the speaker terminals shorted out? were they being driven hard when they went?
Owen
first thing to do is rip one of them open and take some pic's and try and track down any components that look obviously burnt / blown to pieces and take pic's of them for us..
also do you know any info on how they failed? were the speaker terminals shorted out? were they being driven hard when they went?
Owen
Amplifiers
First of all, my digicam is away for the week The Pioneer GM-D500M was recalled by pioneer because of an overheat issue when loaded at two ohms. I sold the amp to a friend who loaded the amp and wanted his money back. It has sat in the closet for over a year. Pioneer may still help but I am unsure.
I opened the earthquake and immediately notice a loose heatsink. I thought maybe It had been tampered with but it appears thayt two of the three transistors are lightly charred and cracked. They are RFP50N06. The PCB is marked IRFZ44 at these locations. I would like to learn to test these as well as all transistors
Thank you very much
Joe
First of all, my digicam is away for the week The Pioneer GM-D500M was recalled by pioneer because of an overheat issue when loaded at two ohms. I sold the amp to a friend who loaded the amp and wanted his money back. It has sat in the closet for over a year. Pioneer may still help but I am unsure.
I opened the earthquake and immediately notice a loose heatsink. I thought maybe It had been tampered with but it appears thayt two of the three transistors are lightly charred and cracked. They are RFP50N06. The PCB is marked IRFZ44 at these locations. I would like to learn to test these as well as all transistors
Thank you very much
Joe
they are fairly easy too test if you have a DMM with transistor checker function, not sure how to do it with a DMM without one but i am sure someone will know how too, if you don't have a DMM (digital multi meter) then i highly recomend you buy one (even a cheap one, all i have is a cheap one but it does the job fine)
Have you tested the pioneer out yourself with a 4 or 8 ohm load? or is the problem only if it is loaded below 4 ohm's?
as for the earthquake, those output devices will need replaceing, but it is adviseable to first check the other components around them too make sure tht they are the only components that have blown. Could be that at some time it has had the speaker terminals shorted or has been run with too low load and burned up, i'm not really familiar with the earthquake amp's.
but before we start with anything you will need to get (if you don't already have) a DMM and a soldering iron at the vey least.
Owen
Have you tested the pioneer out yourself with a 4 or 8 ohm load? or is the problem only if it is loaded below 4 ohm's?
as for the earthquake, those output devices will need replaceing, but it is adviseable to first check the other components around them too make sure tht they are the only components that have blown. Could be that at some time it has had the speaker terminals shorted or has been run with too low load and burned up, i'm not really familiar with the earthquake amp's.
but before we start with anything you will need to get (if you don't already have) a DMM and a soldering iron at the vey least.
Owen
Amplifiers
I have been checking the Amps. The earthquake had a loose heatsink/fet retainer. 2 of six Fets appeared charred. Notknowing how to test them, I just measured resitance in all possible combinationations. The 2 had continuity in all combinations. The other four had no continuity except in one combination which gave a measurement of 10.xx Ohms on all four. I am hoping that the loose heat sink is the only cause for cooked Fets. It was the most obvious.
The Pioneer was loaded down and now blows fuses on Power up. No load no source.The Power transister in this are in pairs not a row of six. They all appear OK so I may need some proper testing methods.
Thanks again
Joe
I have been checking the Amps. The earthquake had a loose heatsink/fet retainer. 2 of six Fets appeared charred. Notknowing how to test them, I just measured resitance in all possible combinationations. The 2 had continuity in all combinations. The other four had no continuity except in one combination which gave a measurement of 10.xx Ohms on all four. I am hoping that the loose heat sink is the only cause for cooked Fets. It was the most obvious.
The Pioneer was loaded down and now blows fuses on Power up. No load no source.The Power transister in this are in pairs not a row of six. They all appear OK so I may need some proper testing methods.
Thanks again
Joe
Amplifrier
I just ordered two Fets Fairchilds RFP50N06 $1.35 each. I will let you know how it works out. I will be smart and put that one away for now.
On to the pioneer
I just ordered two Fets Fairchilds RFP50N06 $1.35 each. I will let you know how it works out. I will be smart and put that one away for now.
On to the pioneer
It looks like all of the FETs failed. Even if they didn't, if they're in the power supply section you need to replace all 6 of them. If they're mismatched, the amp will fail again.
Double-check the FETs using the procedure shown ~1/2 of the way down this page:
http://www.bcae1.com/ampfail.htm
The meter needs to be set to 'diode check'.
Double-check the FETs using the procedure shown ~1/2 of the way down this page:
http://www.bcae1.com/ampfail.htm
The meter needs to be set to 'diode check'.
FETs
Awesome tests, thank you. Two of these four failed from the pioneer. These FETs are ST309235 but I can't find them on STMicro page. There is another number below. It is P16NF.
Thanks a million
Awesome tests, thank you. Two of these four failed from the pioneer. These FETs are ST309235 but I can't find them on STMicro page. There is another number below. It is P16NF.
Thanks a million
FET
I am getting ready to order FET. The tests worked well. I tested P12PF the same way and all failed. I am wondering if the test procedure is different for P-Channel FET
Thanks again I am really enjoying myself and accomplishing something (not to mention saving a bundle while getting these amps running
I am getting ready to order FET. The tests worked well. I tested P12PF the same way and all failed. I am wondering if the test procedure is different for P-Channel FET
Thanks again I am really enjoying myself and accomplishing something (not to mention saving a bundle while getting these amps running
Reverse the meter leads for p-channels. Swap the meter leads (where they plug into the meter) and then test the p-channels the same as you did for the n-channels.
FET
Thanks Perry, you are making this alot more straight forward. It is so much nicer to be learning rather than chasing my tail in a pile of guesses.
Thanks Perry, you are making this alot more straight forward. It is so much nicer to be learning rather than chasing my tail in a pile of guesses.
FET
I swapped leads. The results seemed more logical. 1 good 2 leaking 1 shorted. Does that seem like the results I should get from an amp that has a recall? That's the pioneer that was loaded to 2 Ohm. Of 4 N-Channel and 4 P-Channel, about half of my fets are Cooked. It is a mono only AMP and the 8 FET were all on the same heatsink. Although I don't understand the circuit.
Thanks
I swapped leads. The results seemed more logical. 1 good 2 leaking 1 shorted. Does that seem like the results I should get from an amp that has a recall? That's the pioneer that was loaded to 2 Ohm. Of 4 N-Channel and 4 P-Channel, about half of my fets are Cooked. It is a mono only AMP and the 8 FET were all on the same heatsink. Although I don't understand the circuit.
Thanks
There would be no way to predict what condition the parts would be in when they failed. The recall would be simply because the parts were failing under normal operating conditions.
Ok, I am new at this also but from what I have been reading, you cannot just change one FET but you must change them all due to differences between the new and the old tolerances? Polo..
Yes.
All that are running in parallel groups must be changed when one in the group fails. For example, if you have 4 output transistors in parallel and one of that group fails, all 4 must be replaced.
If the amplifier has 4 transistors for the positive half of the output and 4 for the negative half of the output and one of the 4 in the top half (connected to the positive power supply rail) fails, all 4 of that group must be replaced. If the amp failed under normal operating conditions, replacing only those 4 may be acceptable. If the amp failed because a speaker wire shorted to ground, it may be best to replace both the upper 4 AND the lower 4 even though the lower 4 seem to be fine. Since output transistors are generally inexpensive, it's well worth spending a little more to replace them all.
All that are running in parallel groups must be changed when one in the group fails. For example, if you have 4 output transistors in parallel and one of that group fails, all 4 must be replaced.
If the amplifier has 4 transistors for the positive half of the output and 4 for the negative half of the output and one of the 4 in the top half (connected to the positive power supply rail) fails, all 4 of that group must be replaced. If the amp failed under normal operating conditions, replacing only those 4 may be acceptable. If the amp failed because a speaker wire shorted to ground, it may be best to replace both the upper 4 AND the lower 4 even though the lower 4 seem to be fine. Since output transistors are generally inexpensive, it's well worth spending a little more to replace them all.
FET
My Pioneer was rated as 2 Ohm Stable but Pioneer recalled them, being a fire hazard.Not 2 Ohm stable. I am inexperienced, but while testing my FETs, a few of them didn't quite short but my meter momentarily wen't from OL to 00.00 and then back. I tested numerous times with same results. I assume that those are the ones that aren't cooked but are on their way out. As Perry said they are cheap enough. Keep the borderline ones in a junk box for projects. Or throw them out. My retailer wants $4.95 Canadian each for FET. I can get 10 from digi-key for $8.40
My Pioneer was rated as 2 Ohm Stable but Pioneer recalled them, being a fire hazard.Not 2 Ohm stable. I am inexperienced, but while testing my FETs, a few of them didn't quite short but my meter momentarily wen't from OL to 00.00 and then back. I tested numerous times with same results. I assume that those are the ones that aren't cooked but are on their way out. As Perry said they are cheap enough. Keep the borderline ones in a junk box for projects. Or throw them out. My retailer wants $4.95 Canadian each for FET. I can get 10 from digi-key for $8.40
If the meter shows something other than OL but returns to OL, it doesn't mean the transistor is defective. If your meter is quick to react AND the gate has a relatively high capacitance, the meter reading may show the capacitance being charged. This only happens when you're checking between the gate and the other terminals.
If you set the meter to ohms (or diode check - which isn't quite as sensitive) and you have no continuity between the gate and the other terminals, that's an indication that the gate is OK. If you show any signs of continuity from the from the gate to either of the other terminals, the FET is defective. Keep in mind that this only applies to 'enhancement mode' FETs (the only type used as high power/ high current devices in car amplifiers).
To help you understand the test...
Testing for continuity between the gate and the other terminals tells you if the thin insulating layer of the MOSFET is still intact. If it is damaged, you'll generally see continuity to the Drain (center) terminal. If it's damaged, it doesn't matter what you read on the other terminals. The FET is defective.
When testing between the other terminals (the drain and source), you should 'see' the intrinsic diode (~0.45 volts on diode check with a Fluke meter). With the meter leads reversed, you should read a completely open circuit. The reason that you have to follow a specific order in the test is to assure that the transistor is off when making the measurements. If you go out of order, you may charge the gate of the FET. If it's charged, the transistor will turn on and it may appear to be defective (it would show leakage - electrical leakage).
If you download the datasheet for the FET, you'll see the intrinsic diode shown as a zener diode connected between the drain and source.
I know that this is probably more than you wanted to know but it's important to know why the testing procedure is laid out in a particular order.
If you set the meter to ohms (or diode check - which isn't quite as sensitive) and you have no continuity between the gate and the other terminals, that's an indication that the gate is OK. If you show any signs of continuity from the from the gate to either of the other terminals, the FET is defective. Keep in mind that this only applies to 'enhancement mode' FETs (the only type used as high power/ high current devices in car amplifiers).
To help you understand the test...
Testing for continuity between the gate and the other terminals tells you if the thin insulating layer of the MOSFET is still intact. If it is damaged, you'll generally see continuity to the Drain (center) terminal. If it's damaged, it doesn't matter what you read on the other terminals. The FET is defective.
When testing between the other terminals (the drain and source), you should 'see' the intrinsic diode (~0.45 volts on diode check with a Fluke meter). With the meter leads reversed, you should read a completely open circuit. The reason that you have to follow a specific order in the test is to assure that the transistor is off when making the measurements. If you go out of order, you may charge the gate of the FET. If it's charged, the transistor will turn on and it may appear to be defective (it would show leakage - electrical leakage).
If you download the datasheet for the FET, you'll see the intrinsic diode shown as a zener diode connected between the drain and source.
I know that this is probably more than you wanted to know but it's important to know why the testing procedure is laid out in a particular order.
Pioneer GM-D500...
If it's anything like the GM-D510 that just came into the shop, replace the original FETs and send it back to pioneer. It looks like there isn't enough heatsinking on the driver IC (TDA7570). On this one, the board under the IC shows signs of serious heat stress. The driver IC would be tough to replace and is likely dead on your amplifier. It's likely that they're making some significant mods to the boards.
Is the board under your driver IC discolored?
If it's anything like the GM-D510 that just came into the shop, replace the original FETs and send it back to pioneer. It looks like there isn't enough heatsinking on the driver IC (TDA7570). On this one, the board under the IC shows signs of serious heat stress. The driver IC would be tough to replace and is likely dead on your amplifier. It's likely that they're making some significant mods to the boards.
Is the board under your driver IC discolored?
Driver IC
I have no idea what the driver IC does but mine is not discoloured. The model you are working on was a replacement for the recalled GM-D500M. Thanks so much for help by the way. I decided to put the time in to the Earthquake more workspace inside. I called Pioneer Canada, they offered no help. Pioneer USA says they will give me a refund. Just waiting.
I have no idea what the driver IC does but mine is not discoloured. The model you are working on was a replacement for the recalled GM-D500M. Thanks so much for help by the way. I decided to put the time in to the Earthquake more workspace inside. I called Pioneer Canada, they offered no help. Pioneer USA says they will give me a refund. Just waiting.
- Status
- Not open for further replies.