Hi everyone, I have a A600 and a A300 that i bought new. Both are not working now and i am looking to rebuild/fix them. I just bought a working A300 for a good deal and i wanted to use it as a reference to look at in the repair. The A300 that i just bought was repainted and when i opened it up it has the same board number at the A600 with a different rev letter????hummmm So i am sure it is a A600 as it is the same size as my other A600 i got new.
I have been looking around this site and seen lots of info, but i was just wondering if i could get a link to what i should replace in my A600 and A300 to make them as good as new. I would like to replace all mosfets, maybe caps if need be and another parts that would be beneficial.
The board number is 75-2164 REV N (one i got new in 90)
Amp i just got 75-2164 REV U (said to be a A300)??? does anyone know for sure as it is the same size chassis as A600 that i bought.
A300 i bought new is 75-2084 REV F
I have been looking around this site and seen lots of info, but i was just wondering if i could get a link to what i should replace in my A600 and A300 to make them as good as new. I would like to replace all mosfets, maybe caps if need be and another parts that would be beneficial.
The board number is 75-2164 REV N (one i got new in 90)
Amp i just got 75-2164 REV U (said to be a A300)??? does anyone know for sure as it is the same size chassis as A600 that i bought.
A300 i bought new is 75-2084 REV F
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Some amps like the older orion amps and some of the older PG amps have significant problems with capacitors (leakage of electrolyte causing damage to the board and other problems). I've repaired quite a few of these and don't remember seeing any leaky capacitors.
The power supply FETs probably don't need to be replaced (except for those in the power supply that failed). The output stage uses BJTs, not FETs. They may have failed in the amp with the blown supply.
Unless you have good equipment (soldering/desoldering) and can replace parts without damaging the board (some people do a lot of damage when replacing parts), I'd suggest leaving the working amps as they are.
The power supply FETs probably don't need to be replaced (except for those in the power supply that failed). The output stage uses BJTs, not FETs. They may have failed in the amp with the blown supply.
Unless you have good equipment (soldering/desoldering) and can replace parts without damaging the board (some people do a lot of damage when replacing parts), I'd suggest leaving the working amps as they are.
Thanks very much for the reply Perry. I have done me fair share of soldering and desoldering on circuit boards so i am not worried of my work. I seen a list on here a long time ago with values of all the M/Q's with replacements part numbers, would you know what thread that was under Perry. As for the two boards with same part numbers and size they must be the same. The A300 with the blown RFP25N05, do they still make these or is there a new number for them.
One last question for now... i want to clean up the thremal compound that PPI loved. Has anyone use CPU thermal paste, it works amazing on heat transfer. and i have lots of it..lol
One last question for now... i want to clean up the thremal compound that PPI loved. Has anyone use CPU thermal paste, it works amazing on heat transfer. and i have lots of it..lol
The computer paste isn't really that much better. I've compared the arctic silver 5 against Dow Corning 340 (actually dow 340 and dow 5 mixed) and there was essentially no difference. This was on two identical video cards being run in crossfire mode. I did it with video cards because there were built-in thermal sensors and so that I could monitor their loads. For those who want to argue about this, don't expect an argument from me. I'll simply ignore the post. I have to include this because there is always someone who wants to argue this point with no real, controlled tests.
I'd suggest that you use a different FET like the IRFZ44 (any version will work). You'll also need to replace the gate resistors if they're greater than 100 ohms. Anything 100 ohms or less should be OK. Values between 68 and 100 ohms are good choices.
When you get the amps working, you need to compare the rail voltage in each amp. The 300 may have a different transformer or different regulation than the 600. They may also be identical.
I don't remember the thread.
If you want to replace the parts and are capable of replacing them without damaging the amp, feel free to do so. I generally suggest leaving amps as they are because I've seen too many butchered amps.
I use a lot of Panasonic FC capacitors as replacements.
I'd suggest that you use a different FET like the IRFZ44 (any version will work). You'll also need to replace the gate resistors if they're greater than 100 ohms. Anything 100 ohms or less should be OK. Values between 68 and 100 ohms are good choices.
When you get the amps working, you need to compare the rail voltage in each amp. The 300 may have a different transformer or different regulation than the 600. They may also be identical.
I don't remember the thread.
If you want to replace the parts and are capable of replacing them without damaging the amp, feel free to do so. I generally suggest leaving amps as they are because I've seen too many butchered amps.
I use a lot of Panasonic FC capacitors as replacements.
Sorry Perry can you cancel that last question as i had a brain cramp..lol I just dug into the A300. Q60 to 63 all need replacing plus the gate resistors. Are there known reasons for Q60and Q63 to split in two.I also found Q1,2,3,7,8,9 to have BDT82. Some of the BDT82 have different production dates by four weeks, would it be good to replace them with a matching set.
FETs used in the power supply often split open or burn. I'm guessing that they crack because of expansion of internal components when they burn (due to excessive current) but there may be another reason.
Having matched components will help increase reliability but since these have been in the amp for a very long time and have not failed, they're likely matched closely enough.
Having matched components will help increase reliability but since these have been in the amp for a very long time and have not failed, they're likely matched closely enough.
I'm just trying to get this all clear Perry as i am getting some help from 1moreamp to (thanks MrC). The power supply uses FETs that i could replace with Z44's. What can i use to replace the BDT82 and BDT81 mosfets?
2N6488 and 2N6491 are the usual devices PPI used after the BDT .
here is a link to the BDT line of devices in case you stay with them if they are available to you.
http://www.halfin.com/comset/catalogue/bdt81-82-83-84-85-86-87-88.pdf
and
BDT82 Datasheet. BDT82 Equivalent, PDF Data Sheets - Parameters and Characteristics. Electronic Component Catalog.
Thanks for the links1MA. I just need to cross reference them now. Is there any good reason to go bigger on the Volts or Amps specs for these chips. Eg, more robust, higher output, more efficiency . I was thinking cause most chips come in 50 count packaging i might do all four amps (A200, A300, 2xA600) i have with new chips.
I'd also suggest that you use the 2N6488 and 2N6491. There aren't any transistors significantly better.
Thanks guys for all the info. I will post pictures when I am done monuting the amps to the cooling rack that I am building for the boards. Thanks Hispeedguy
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