Hello, I've got a Peavey 1.3k in need of some output transistors that I couldn't to save my life find on the web. I emailed Peavey but they didn't respond. I'd appreciate the help if anyone has any info or possibly a service manual. There Motorolas, 70484200 and 70474200. I know Motorola Semiconductor is now On Semiconductor and in fact one transistor has the same number but with On instead of an M but there was no listing on On's site.
where is the triac please
Hi
I am fixing up a 1.3K and I am not sure yet if I need to replace any output transistors on the power stage. I suspect I will because there is a lonely little resistor down in between those big resistor banks and it's burned to a crisp.
If anyone could tell me the value of that resistor and what it does I would appreciate it please.
So assuming I do need to replace an output transistor or 10, can you please tell me where the triac is and what I should replace it with (if not the same value) and why I should replace it at all?
I was interested that you wrote about a breaker bar. I have heard about these before on Peaveys. I was pretty surprised when I blew this amp that there appears to be no protection on the amp outputs. One of the preamps has significant burn damage from something, and as I said this resistor on the power stage is burned which suggests (to me anyway; something different to you perhaps) that there is trouble on the power board.
But although it was smoking like a 60s talk show host and the amp was blaring hum, nothing blew to shut it down. Not the front breaker, not any power fuses, and I see no fuse protection on the outputs, so had this decided to go DC I would have probably lost a pair of JBLs. So, what is the breaker bar supposed to protect? I see a few posts where guys want to disable this thing, and they are continually warned against it, but if it does as much for them as it did for us, why not disable it?
Thanks very much for your time
Phil
Hi
I am fixing up a 1.3K and I am not sure yet if I need to replace any output transistors on the power stage. I suspect I will because there is a lonely little resistor down in between those big resistor banks and it's burned to a crisp.
If anyone could tell me the value of that resistor and what it does I would appreciate it please.
So assuming I do need to replace an output transistor or 10, can you please tell me where the triac is and what I should replace it with (if not the same value) and why I should replace it at all?
I was interested that you wrote about a breaker bar. I have heard about these before on Peaveys. I was pretty surprised when I blew this amp that there appears to be no protection on the amp outputs. One of the preamps has significant burn damage from something, and as I said this resistor on the power stage is burned which suggests (to me anyway; something different to you perhaps) that there is trouble on the power board.
But although it was smoking like a 60s talk show host and the amp was blaring hum, nothing blew to shut it down. Not the front breaker, not any power fuses, and I see no fuse protection on the outputs, so had this decided to go DC I would have probably lost a pair of JBLs. So, what is the breaker bar supposed to protect? I see a few posts where guys want to disable this thing, and they are continually warned against it, but if it does as much for them as it did for us, why not disable it?
Thanks very much for your time
Phil
i have fixed a few pv1.3k amps, and hate them! however i will try and help you.... the triacs are at both ends of the output board, this is the only protection, im sure there is a diac or transistor that works in conjunction with it. the triac is a T220 package three legs and bolted to pcb as i remember, make sure you change this before you replace any outputs! otherwise if its gone short last time , you will destroy your new transistors ...
have paper schematics here if you need any help...
lots of small resistors between the large resistor banks....
have paper schematics here if you need any help...
lots of small resistors between the large resistor banks....
I just fixed one of these POS...
I have Schematics from peavey. email me at tetech2@doitnow.com and i can email them to you. they are in PDF form.
Zc
I have Schematics from peavey. email me at tetech2@doitnow.com and i can email them to you. they are in PDF form.
Zc
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