Hello All,
I am repairing my CS800X amp. I have 3 shorted power transistors (9312,9930,9737).
Who knows the cross-reference numbers?
Should I replace all or partial (which pair or group) of the power transistors or just the shorted ones? There are 20 power transistors total both sides (Peavey's quasi-complementary designs typically uses 10 per amp correct?)
Are there usually other components that need replacing as a general rule with this type of failure? Voltages I need to check? The power supply is running as designed. Obviously the main CB trips quickly, but the 2 fuses (1A) in what appears to be the protection circuit are holding and good.
What is a good source for buying these power devices? The numbers on the devices do not cross or at least I can not locate them via Google!
Thanks for the help.
Billy
I am repairing my CS800X amp. I have 3 shorted power transistors (9312,9930,9737).
Who knows the cross-reference numbers?
Should I replace all or partial (which pair or group) of the power transistors or just the shorted ones? There are 20 power transistors total both sides (Peavey's quasi-complementary designs typically uses 10 per amp correct?)
Are there usually other components that need replacing as a general rule with this type of failure? Voltages I need to check? The power supply is running as designed. Obviously the main CB trips quickly, but the 2 fuses (1A) in what appears to be the protection circuit are holding and good.
What is a good source for buying these power devices? The numbers on the devices do not cross or at least I can not locate them via Google!
Thanks for the help.
Billy
Generaly MJ15022/15023 or 15024/15025 are the usual power horses
for the final stage , they were often used also as drivers in some Peawey amps
that had a triple EF output stage.
for the final stage , they were often used also as drivers in some Peawey amps
that had a triple EF output stage.
I don't think they are quasi-comp. The followup CS800s has fully complementary output transistors, and the predecessor CS800b also has those. With the .33 ohm emitter resistors, you should probably buy extras and match the Vbe readings of the ones you use. Or you can buy a full set from Peavey, and they should take care of it.
I found O.T.'s that pass the double diode test, can still fail due to damage from the meltdown event. I found that shorting b to e and putting 18VDC on c to be, (or -18v on pnp) and measuring the leakage current with a DVM, can find the ones that are going to explode with full voltage. They have more leakage than new ones.
You're 100 miles from newark.com in NC. I buy On semi stuff from them. They have stocked MJ15024 and 25 when I have looked. If you live in a house or apartment, check USPS priority as the shipping option to save money over UPS. Check "hold and ship all at once" under shipping options to avoid having two boxes sent on different days. Don't buy stuff not in stock, and don't buy "direct ship" items, they come from the UK with a $28 per item shipping cost.
Don't be surprised if driver transistors, predrivers, and a lot of little stuff is blown up too. the little 50v ceramic capacitors are the hardest to test, for me. Zener diodes, op amps, driver collector resistors, I had a lot of stuff blown up in the PV1.3k. Don't forget to use a variac or light bulb box to lower the AC voltage on startup. It limits the size of the O.T. explosions if you don't get all the stressed ones out the first time.
I found O.T.'s that pass the double diode test, can still fail due to damage from the meltdown event. I found that shorting b to e and putting 18VDC on c to be, (or -18v on pnp) and measuring the leakage current with a DVM, can find the ones that are going to explode with full voltage. They have more leakage than new ones.
You're 100 miles from newark.com in NC. I buy On semi stuff from them. They have stocked MJ15024 and 25 when I have looked. If you live in a house or apartment, check USPS priority as the shipping option to save money over UPS. Check "hold and ship all at once" under shipping options to avoid having two boxes sent on different days. Don't buy stuff not in stock, and don't buy "direct ship" items, they come from the UK with a $28 per item shipping cost.
Don't be surprised if driver transistors, predrivers, and a lot of little stuff is blown up too. the little 50v ceramic capacitors are the hardest to test, for me. Zener diodes, op amps, driver collector resistors, I had a lot of stuff blown up in the PV1.3k. Don't forget to use a variac or light bulb box to lower the AC voltage on startup. It limits the size of the O.T. explosions if you don't get all the stressed ones out the first time.
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