Hi guy's.
I'm trying to repair P800.2 amplifier that I got from a friend. It doesn’t power up so I opened it up. Some pictures of the inside with visible burn marks.
Fried power supply FET:
Burnt source resistors:
Fried drive circuit transistor?? Q2 called p2G = PMBTA56:
Burnt and broken trace:
It seems that the left side of the amp is blown for most of the part.
The right side is good (No leaks in output Fet’s between Gate and Drain / Source resistors measure 0.1Ohm’s).
After removing the left side and measuring most of the components this is what I found:
As you can see I desoldered most of the defective components and fixed the broken trace.
I've made a list of components that need to ordered so far:
Does anyone know a good alternative part?
If I need to measure some other parts let me know
I'm trying to repair P800.2 amplifier that I got from a friend. It doesn’t power up so I opened it up. Some pictures of the inside with visible burn marks.
Fried power supply FET:
Burnt source resistors:
Fried drive circuit transistor?? Q2 called p2G = PMBTA56:
Burnt and broken trace:
It seems that the left side of the amp is blown for most of the part.
The right side is good (No leaks in output Fet’s between Gate and Drain / Source resistors measure 0.1Ohm’s).
After removing the left side and measuring most of the components this is what I found:
As you can see I desoldered most of the defective components and fixed the broken trace.
I've made a list of components that need to ordered so far:
- 10x IRF3205 (Powersupply FET replacement for the MTP75N05HD)
- 12x IRF9640
- 12x IRF640N
- 10x MPSA56
- 10x MPSA06
- 30x 0,1Ω 2W resistor
Does anyone know a good alternative part?
If I need to measure some other parts let me know
Philips uses a P in the prefix. Motorola uses an M. The MMBTA56 is essentially the same part.
Check the gate resistors for the power supply FETs.
Also check all of the surface mount resistors that are connected to the gate AND to the source resistors for the outputs. When the source resistors open, the SMD resistors often open.
The diode at the end of the burned trace is likely shorted.
You should read through the following threads if you haven't done so:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99215
http://www.diyaudio.com/forums/showthread.php?postid=1761203#post1761203
http://www.diyaudio.com/forums/showthread.php?postid=1737203#post1737203
Check the gate resistors for the power supply FETs.
Also check all of the surface mount resistors that are connected to the gate AND to the source resistors for the outputs. When the source resistors open, the SMD resistors often open.
The diode at the end of the burned trace is likely shorted.
You should read through the following threads if you haven't done so:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99215
http://www.diyaudio.com/forums/showthread.php?postid=1761203#post1761203
http://www.diyaudio.com/forums/showthread.php?postid=1737203#post1737203
Thank's Perry for reviewing my problem.
Great stuff, I'll just replace the SOT-23 PMBTA56 with a TO-92 MPSA56
I've measured the Gate resistors from the Power supply FET's.
The readings of the Gate resistors of the output FET's.
They all (R274, R244, R242 and R240) measure 0,4Ω. 0,4Ω - 0,3Ω (internal resistance DMM) = 0,1Ω
The Source resistors I desoldered measured between 180Ω and 3KΩ.
Correct!! The diode was shorted indeed shorted, gave me a perfect .000 in both directions! Its a 1N4003 diode which is rated to 200V peak.. I only have a bunch of 1N4001 diodes so I'll have to order those.
Yes, I've read those threads for most of the part. To be honest, I came across one of those threads when I was looking for repair information about this amplifier.
Thanks for the help so far Perry, I've learned allot from the Basic Car Audio Amplifier Repair guide!
If there is anything I have to measure before I order everything, let me know. Thanks again
Great stuff, I'll just replace the SOT-23 PMBTA56 with a TO-92 MPSA56
I've measured the Gate resistors from the Power supply FET's.
- R8 [680] = 68,5Ω
- R10 [680] = 68,5Ω
- R58 [680] = 69Ω
- R59 [680] = 68,9Ω
The readings of the Gate resistors of the output FET's.
- R248 [510] = 51,8Ω
- R249 [510] = 51,7Ω
- R250 [510] = 51,5Ω
- R251 [510] = 51,6Ω
- R252 [510] = 55,2Ω <- ?
- R275 [510] = 52,5Ω <- ?
- R276 [510] = 51,5Ω
- R277 [510] = 51,9Ω
- R278 [510] = 51,7Ω
- R279 [510] = 51,6Ω
They all (R274, R244, R242 and R240) measure 0,4Ω. 0,4Ω - 0,3Ω (internal resistance DMM) = 0,1Ω
The Source resistors I desoldered measured between 180Ω and 3KΩ.
Correct!! The diode was shorted indeed shorted, gave me a perfect .000 in both directions! Its a 1N4003 diode which is rated to 200V peak.. I only have a bunch of 1N4001 diodes so I'll have to order those
.Yes, I've read those threads for most of the part. To be honest, I came across one of those threads when I was looking for repair information about this amplifier.
Thanks for the help so far Perry, I've learned allot from the Basic Car Audio Amplifier Repair guide!
If there is anything I have to measure before I order everything, let me know. Thanks again
I'd replace the two that have the question mark.
You need to replace all of the 0.1 ohm resistors.
If you haven't done so, double-check the resistors directly connected to the source resistors. It's rare to have open source resistors and not have at least two of the SMD resistors (connected to the source resistors) fail.
Use the MMBTA56 instead of the TO-92 case transistor. I've done it before but it's difficult to do it without stressing the pads. Replacing the SMD transistor is easier than replacing through-hole transistors.
You need to replace all of the 0.1 ohm resistors.
If you haven't done so, double-check the resistors directly connected to the source resistors. It's rare to have open source resistors and not have at least two of the SMD resistors (connected to the source resistors) fail.
Use the MMBTA56 instead of the TO-92 case transistor. I've done it before but it's difficult to do it without stressing the pads. Replacing the SMD transistor is easier than replacing through-hole transistors.
I have placed a bunch of 51Ω SMD resistors to my order.
Desoldered the other 0,1Ω Source resistors of the Left output.
How many Watt's do these 0,1Ω resistors have to be? I can choose between 2 or 5 Watt.
After desoldering the 0,1Ω Source resistors, I measured the resistors connect to the Source trace/pad:
I guess these seem alright. The ones that are a bit off are R243 and R245. Should I replace them?
Well the problem about the MMBTA56 is that I can's find a shop who sells it. Reichelt.de only sells the TO-92 variant so I have to settle with the MPSA56.
To be on the safe side, I'm also going to replace transistor Q1, Q3 and Q4 in this picture:
Do you know a good alternative transistor for the MPSA56 and MPSA06? If so, I'll have to look for them if they are available in both TO-92 and SOT-23 case.
Otherwise I have to go with this solution:
Thanks again for your help
Desoldered the other 0,1Ω Source resistors of the Left output.
How many Watt's do these 0,1Ω resistors have to be? I can choose between 2 or 5 Watt.
After desoldering the 0,1Ω Source resistors, I measured the resistors connect to the Source trace/pad:
- R237 [101] = 101,1Ω
- R239 [101] = 101,6Ω
- R241 [101] = 101,4Ω
- R243 [101] = 100,8Ω <- ?
- R245 [101] = 102,5Ω <- ?
- R265 [101] = 101,0Ω
- R267 [101] = 101,5Ω
- R269 [101] = 101,0Ω
- R271 [101] = 101,1Ω
- R273 [101] = 101,3Ω
I guess these seem alright. The ones that are a bit off are R243 and R245. Should I replace them?
Well the problem about the MMBTA56 is that I can's find a shop who sells it
. Reichelt.de only sells the TO-92 variant so I have to settle with the MPSA56.To be on the safe side, I'm also going to replace transistor Q1, Q3 and Q4 in this picture:
Do you know a good alternative transistor for the MPSA56 and MPSA06? If so, I'll have to look for them if they are available in both TO-92 and SOT-23 case.
Otherwise I have to go with this solution:
- Replace Q2 and Q3 with MPSA56's
- Replace Q1 and Q4 with MPSA06's (these two are originally 1GM = MMBTA06)
Thanks again for your help
Mouser has a worldwide site.
http://www.mouser.com/localsites/
The original resistors are 2w.
The 100 ohm resistors are within tolerance.
Look for these two resistors and check them. One should be marked 390. The other should be marked 470.
http://www.mouser.com/localsites/
The original resistors are 2w.
The 100 ohm resistors are within tolerance.
Look for these two resistors and check them. One should be marked 390. The other should be marked 470.
Thanks for the webshop
Great!
Are you referring to R390 and R470? I can't find any of those
(maybe I need a new pair of glasses, lol)If you are, please give me a hint on where to look.
I've got a schematic of this amplifier that I recieved from RF tech a couple of days ago. If you need it or any pictures of the amplifier, let me know
Thanks Perry, I'll add some of those to my order form.
If there is something I need to measure or if there are some parts that need to be ordered (just in case, for spare parts), please let me know.
From the parts that 'need' to be ordered I've added a couple of extra just in case something goes wrong.
If there is something I need to measure or if there are some parts that need to be ordered (just in case, for spare parts), please let me know.
From the parts that 'need' to be ordered I've added a couple of extra just in case something goes wrong.
You guys are very kind to share your knowledge about amplifiers and other electronics. Especially taking the time and effort of helping people all over the world.
In the Netherlands its hard to find people with knowledge about Rockford Fosgate amps because they are kinda rare.
About the repair of my P800.2... I'm kinda broke right now so I have to wait until I receive my loan/pay check later this week.. (I hope )
I plan on ordering the components at Farnell.com. Before I make the order I would appreciate it if you guys would check my order for any wrong components or if you would recommend other (better) components instead.
Untill then, I'll keep you posted
In the Netherlands its hard to find people with knowledge about Rockford Fosgate amps because they are kinda rare.
About the repair of my P800.2... I'm kinda broke right now so I have to wait until I receive my loan/pay check later this week.. (I hope
)I plan on ordering the components at Farnell.com. Before I make the order I would appreciate it if you guys would check my order for any wrong components or if you would recommend other (better) components instead.
Untill then, I'll keep you posted
Whoops, Sorry but some other things had come up..
Here's the list:
Any insight, tips or recommendations for other parts etc are welcome. Thanks
Here's the list:
Code:
[u]Amount[/u] [u]Product description[/u] [u]Manufacturer - Article[/u] [u](comment)[/u]
10x MOSFET, N, 55V, 98A, TO-220 INTERNATIONAL RECTIFIER - IRF3205PBF (Replacement for the original MTP75N05HD power supply transistors)
15x MOSFET, P, -200V, -11A, TO-220 VISHAY FORMERLY INTERNATIONAL RECTIFIER - IRF9640PBF (Output transistor)
15x MOSFET, N, 200V, 18A, TO-220 VISHAY FORMERLY INTERNATIONAL RECTIFIER - IRF640PBF (Output transistor)
20x TRANSISTOR, PNP, TO-92 FAIRCHILD SEMICONDUCTOR - MPSA56_D27Z (Drive circuit transistor)
20x TRANSISTOR, NPN, TO-92 FAIRCHILD SEMICONDUCTOR - MPSA06 (Drive circuit transistor)
10x TRANSISTOR, NPN, SMD, SOT-323 FAIRCHILD SEMICONDUCTOR - MMBTA06 (Replacement for Q2 and Q3)
10x TRANSISTOR, PNP, SOT-23 ON SEMICONDUCTOR - MMBTA56LT1G (Replacement for Q1 and Q4)
25x RESISTOR, 0.1 OHM 3W MULTICOMP - MC14718 (Source resistor replacement, 3W instead of 2W and a tolerance of 1%)
5x RESISTOR, 10 OHM 3W MULTICOMP - MC14703 (Replacing R225 and R325 with new ones, just for cosmetic purposes, also 3W and 1% tolerance)
50x RESISTOR, RC11 0805 39R PHYCOMP (YAGEO) - 232273061399 (Replacement for R264, minimum order amount = 50 pieces)
50x RESISTOR, RC11 0805 47R PHYCOMP (YAGEO) - 232273061479 (Replacement for R238, minimum order amount = 50 pieces)
50x RESISTOR, 0805 51R MULTICOMP - MC 0.1W 0805 1% 51R (Spare Gate resistors output, minimum order amount = 50 pieces)
50x RESISTOR, 0805 100R MULTICOMP - MC 0.1W 0805 1% 100R (Spare Source resistors output, minimum order amount = 50 pieces)
10x DIODE, POWER RECTIFIER SPC TECHNOLOGY - 1N4003 (Replacemet diode for shorted diode D3, also going to replace D2)
1x CAPACITOR, 4700UF, 80V NICHICON - LLS1K472MELC (Replacing C25, it has a [URL=http://img.techpowerup.org/090406/P800.2 C25 dent.jpg]dent/scratch on top[/URL])Any insight, tips or recommendations for other parts etc are welcome. Thanks
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