drvtech

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  1. Since the PSA2 is a quazi-complimentary design I need to know which module you are working on. Does it have a + or a - on it? Dave Engstrom Crown Techncial Support Hi dave, As far as i can remember all output transistors are N type devices and all drivers are N type devices, be they + or - modules..... crown used various transistor part numbers over many years...... sounds like some modules have been swapped or previously repaired, (usually all drivers in a psa2 amp are the same part numbers and all outputs are the same part numbers) did you check the good side to see what sort of mix of part numbers the modules have)? silly question but did you download the service manual from the discountinued products section on this site? i have repaired some dc300a amps and had good results using motorola mj15024 T03 devices N type, although appologies to many other people on here who will probably frown upon such a substitute! (all i can say is they worked for me, and im not recommending you follow my path) oh my its like health and safety gone mad!. i suggest you test test and re test all semiconductors on the faulty output boards, there will always be one device you miss! hope this helps a little dave Karlos, Thanks for the suggestions. Yes, I do have all the service documentation. Some of the Crown part numbers are cross referenced to manufacturers' designations, it's just these *ing drivers that are the problem! I've actually got another PSA2 here which I haven't tested yet but I believe to be in working order so I'll have a look at the devices in that too. In response to your comment about them all being the same, the outputs are indeed the same but of course the drivers couldn't be, as one is a PNP and the other is an NPN! Anyway, thanks again for the response and I'll post back any progress I make. All the best Dave Hi dave, yes you are right, (its been a while since i looked inside my sa2....) similar amp except vu meters.... i have 4718 outputs throughout and +ch cpn4580 and -5402 drivers..... im used to dc300a amps which have N channel devices throughout entirely...... im sure i have some used 4718's and maybe 5402 devices here.... according to my info, neg driver p/n 5402 is in fact a 2sc2607) (this is the neg driver in my neg channel output board) and...C6374 is infact a 2SB600 so theres a few more cross references.....(these are crown refs not some *beep*y transistor equivalents book)..... if you work out what the pos version of the 2sc2607 is you maybe going in the right direction..... yes the 4580 doesnt seem to exist!....... will have a look.... cheers dave Now THAT's the sort of info I was looking for - much more food for research. Thanks a million Dave
  2. Since the PSA2 is a quazi-complimentary design I need to know which module you are working on. Does it have a + or a - on it? Dave Engstrom Crown Techncial Support Hi dave, As far as i can remember all output transistors are N type devices and all drivers are N type devices, be they + or - modules..... crown used various transistor part numbers over many years...... sounds like some modules have been swapped or previously repaired, (usually all drivers in a psa2 amp are the same part numbers and all outputs are the same part numbers) did you check the good side to see what sort of mix of part numbers the modules have)? silly question but did you download the service manual from the discountinued products section on this site? i have repaired some dc300a amps and had good results using motorola mj15024 T03 devices N type, although appologies to many other people on here who will probably frown upon such a substitute! (all i can say is they worked for me, and im not recommending you follow my path) oh my its like health and safety gone mad!. i suggest you test test and re test all semiconductors on the faulty output boards, there will always be one device you miss! hope this helps a little dave Karlos, Thanks for the suggestions. Yes, I do have all the service documentation. Some of the Crown part numbers are cross referenced to manufacturers' designations, it's just these *ing drivers that are the problem! I've actually got another PSA2 here which I haven't tested yet but I believe to be in working order so I'll have a look at the devices in that too. In response to your comment about them all being the same, the outputs are indeed the same but of course the drivers couldn't be, as one is a PNP and the other is an NPN! Anyway, thanks again for the response and I'll post back any progress I make. All the best Dave
  3. Since the PSA2 is a quazi-complimentary design I need to know which module you are working on. Does it have a + or a - on it? Dave Engstrom Crown Techncial Support Dave, I replied previously but perhaps it got lost en-route. I'm working on both modules. The 4 output transistors on the + module are blown up but the driver (a C-6374-0) appears to have survived. R303A and B and R300 are also open circuit. On the - module the output transistors check out OK with a meter (on diode test) but the driver (marked 5702#4) is shorted. The passives check out OK. Not knowing what stresses the surviving transistors have been subjected to, my plan was simply to replace all of them. However I am open to suggestions. As one of the drivers was short I thought it would be wise to change the predrivers for the same reason but perhaps I'm overdoing it? Any help regarding actual type numbers for all of these would be gratefully received Kind Regards Dave Vallance
  4. Since the PSA2 is a quazi-complimentary design I need to know which module you are working on. Does it have a + or a - on it? Dave Engstrom Crown Techncial Support The 4 output transistors on the + module are blown up but the driver (a C-6374-0) appears to have survived. R303A and B and R300 are also open circuit. On the - module the output transistors check out OK with a meter (on diode test) but the driver (marked 5702#4) is shorted. The passives check out OK. Not knowing what stresses the surviving transistors have been subjected to, my plan was simply to replace all of them. However I am open to suggestions. As one of the drivers was short I thought it would be wise to change the predrivers for the same reason but perhaps I'm overdoing it? Regards Dave Vallance
  5. I have a PSA2 with one seriously blown up channel. As I understand it MJ21194 is a suitable replacement for the output transistors but can anyone tell me what is a suitable (and available!) replacement for the drivers and predrivers (one PNP and one NPN of each) Thanks for any help and Merry Christmas everyone.