ok i will.Sorry im not on here alot.I have 1n4003 diodes coming.To replace the other diodes on heatsink.
And my multimeter doesnt read the double diodes because my dvom doesnt push even 1 volt.The doubles read when i heat em up a bit.Then my dvom starts reading.0.999 and goes down from there.The diodes do decrease when heated.Thats good.
I'll post the pic in a bit.Thanks Enzo.
And my multimeter doesnt read the double diodes because my dvom doesnt push even 1 volt.The doubles read when i heat em up a bit.Then my dvom starts reading.0.999 and goes down from there.The diodes do decrease when heated.Thats good.
I'll post the pic in a bit.Thanks Enzo.
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heres the wrong photo schematic ,photo of mine.I called Peavey,they confirmed its wrong.The photo doc is wrong ,nothing else.
Your photo you sent me is right. 70473180 pnp all together 70483180 npn all together.And the four drivers in the middle on the separated heatsink.Peavey tech said yours is right.
Your photo you sent me is right. 70473180 pnp all together 70483180 npn all together.And the four drivers in the middle on the separated heatsink.Peavey tech said yours is right.
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An update on the amp.I temporarily had both channels but the bad side to3's got real hot .But im changing all the bias diodes soon and have two mje15025 coming.
I replaced the 22ohm for the turn on triac and it works now with the front switch.
Im jus taking my time.
I will be trying again soon and of course sc187's removed for now.
Bad side to3's were getting real hot but driver 13 pin cable wasnt connected.Thats why i suspect bias,nothing was driving them.No opamps were in the picture from the driver card.Fan would go to full in 8 seconds after turn on.
i'll update again.
I replaced the 22ohm for the turn on triac and it works now with the front switch.
Im jus taking my time.
I will be trying again soon and of course sc187's removed for now.
Bad side to3's were getting real hot but driver 13 pin cable wasnt connected.Thats why i suspect bias,nothing was driving them.No opamps were in the picture from the driver card.Fan would go to full in 8 seconds after turn on.
i'll update again.
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Yes, as I suspected. I asked you to check the LED which would show up as open too since they drop 1.6 v. But they burn green when you turn the power on.
My Craftsman 82144 DVM tries diodes at 2 v. Much more useful.
i need your meter Indianajo .Guess ill buy a craftsman next lol or check the specs better b4 i buy..
I cant find 82144 craftsman anywhere ,sure the # is right? i jus wantsd to chdck it out .
Sears is in bankruptcy, Craftsman is not. Craftsman tools used to be only at Sears, but now they are also sold at other stores, like Lowes and Ace Hardware. Sears sold the brand to get some cash.
I didn't look at them close, but I am sure they are something like Extech or similar, branded for Craftsman.
I would buy a 15 year old Fluke meter in a heartbeat.
I didn't look at them close, but I am sure they are something like Extech or similar, branded for Craftsman.
I would buy a 15 year old Fluke meter in a heartbeat.
Okay today at the worksite I checked my $30 on closeout Tenma 72-7725 DVM. It measured 1.71 v on a yellow LED on diode scale. So it is correct. Also discontinued. https://www.newark.com/tenma/72-772...ErgAg==&ddkey=https:en-US/Element14_US/search
However, I find Newark is usually pretty good at getting decent goods out of *****. Have their own QA department that doesn't miss much. Happy shopping.
However, I find Newark is usually pretty good at getting decent goods out of *****. Have their own QA department that doesn't miss much. Happy shopping.
still working on the cs800x amp.Now the j174 is shorted on one channel and the other has a shorted diode ,it blew two resistors and a ceramic cap.Right under the header pin connector.The flex cable header pin.Its one of the two big diodes on driver board.
The issues stated are on the driver boards .My outputs are good.Outputs arent shorted or getting hot.The 15v regs on the driver boards are good.
I dont know where to begin again lol.
Will the amp work with the j174 fets removed for now?
Thanks for any tips.
It may not can be fixed.Wish there was an abundance of driver boards out there.
The issues stated are on the driver boards .My outputs are good.Outputs arent shorted or getting hot.The 15v regs on the driver boards are good.
I dont know where to begin again lol.
Will the amp work with the j174 fets removed for now?
Thanks for any tips.
It may not can be fixed.Wish there was an abundance of driver boards out there.
When the J174 got blown on my PV-1.3k the transconductance amp U124 was blown too. This is the DDT circuit, I believe the unit will operate without both. J174 are hard to find, and there are two pinouts, the NatSemi one and the Phillips one, so check any units you buy to find out where the gate is.
My unit had 126 parts blown. Not expensive to replace, only the output transistors and rail caps were expensive. I got J174 for $.48 but last ones I bought were $2.30. I think the U100 will operate without both J174 & 8474, but not the DDT function.
It was time consuming to find all the blown parts. My theory was that the blown outputs let rail voltage come forward through the base line and blow up all the parts up forwards. It just took a while to find out what they were. I modified my PV-1.3k by replacing a jumper in the OT base line on the output board with 4 amp blade fuses, and clamping the OT base line to speaker ground on the driver board with 2.1 v 1W zeners. The zeners should blow the fuses if the output transistors blow again.
There was a whole working (allegedly) CS800x in my town for $125 last summer on craigslist. That didn't last long. They are somewhat obsolete in the stage band market because of the heavy transformer. For my home use, the transformer units are not a problem, would inhibit theft the next time somebody broke in here.
Diodes CR132, CR143, and CR104 are all right next to the header pins, so what else is likely to be blown has to do with which one is actually gone. These half amp diodes are about $.07 new and I actually used a bunch of used ones out of a dead PCAT ATX power supply. CR143 is next to Q105 the VI limiter transistor, which is a likely failure candidate in 150 v OT base line events. Not only the PV-1.3k VI limiter transistors all blown, but the sense resistors for the emitter resistors on the output board were all blown too. That unit had one of the .015 uf VI limiter capacitors blown open, too. Those are 50 v caps. It also had some 50 v .1 uf caps blown open around the blown driver op amp. In terms of parts one can leave out, VI limiters are high on my list.
I learned a lot about what the parts of the circuit were for by crawling around the board and replacing blown parts. It was a great tutorial in learning parts of the amp functions, but as an economic practice it would be faster to buy a new class T amp by mowing lawns or shoveling snow. Fixing blown amps is easier on the back, though, and can be done in rainy snowy February days in my comfortable living room. Just finished a PV-4c, lucky only the OT's were blown and the rail caps dried up. The DDT circuit is messed up, but with my TV tuner as sound source at 1W in my den, who needs it? I also changed the shutoff thermostat on the heat sink from 100C to 70 C. That unit had the OT's replaced 4 times previously; likely a design problem with the heat sink. I added more fins to the heat sink, this is diyaudio after all.
In terms of extreme diyaudio projects, one ought to be able to replace the driver board of a CS800x with a LM3886 chip amp board. Think about it.
My unit had 126 parts blown. Not expensive to replace, only the output transistors and rail caps were expensive. I got J174 for $.48 but last ones I bought were $2.30. I think the U100 will operate without both J174 & 8474, but not the DDT function.
It was time consuming to find all the blown parts. My theory was that the blown outputs let rail voltage come forward through the base line and blow up all the parts up forwards. It just took a while to find out what they were. I modified my PV-1.3k by replacing a jumper in the OT base line on the output board with 4 amp blade fuses, and clamping the OT base line to speaker ground on the driver board with 2.1 v 1W zeners. The zeners should blow the fuses if the output transistors blow again.
There was a whole working (allegedly) CS800x in my town for $125 last summer on craigslist. That didn't last long. They are somewhat obsolete in the stage band market because of the heavy transformer. For my home use, the transformer units are not a problem, would inhibit theft the next time somebody broke in here.
Diodes CR132, CR143, and CR104 are all right next to the header pins, so what else is likely to be blown has to do with which one is actually gone. These half amp diodes are about $.07 new and I actually used a bunch of used ones out of a dead PCAT ATX power supply. CR143 is next to Q105 the VI limiter transistor, which is a likely failure candidate in 150 v OT base line events. Not only the PV-1.3k VI limiter transistors all blown, but the sense resistors for the emitter resistors on the output board were all blown too. That unit had one of the .015 uf VI limiter capacitors blown open, too. Those are 50 v caps. It also had some 50 v .1 uf caps blown open around the blown driver op amp. In terms of parts one can leave out, VI limiters are high on my list.
I learned a lot about what the parts of the circuit were for by crawling around the board and replacing blown parts. It was a great tutorial in learning parts of the amp functions, but as an economic practice it would be faster to buy a new class T amp by mowing lawns or shoveling snow. Fixing blown amps is easier on the back, though, and can be done in rainy snowy February days in my comfortable living room. Just finished a PV-4c, lucky only the OT's were blown and the rail caps dried up. The DDT circuit is messed up, but with my TV tuner as sound source at 1W in my den, who needs it? I also changed the shutoff thermostat on the heat sink from 100C to 70 C. That unit had the OT's replaced 4 times previously; likely a design problem with the heat sink. I added more fins to the heat sink, this is diyaudio after all.
In terms of extreme diyaudio projects, one ought to be able to replace the driver board of a CS800x with a LM3886 chip amp board. Think about it.
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