You have an ANALOG AC voltmeter yet? What one does is look at the AC signals through the different stages, and see where things start to go wrong. They don't have to be expensive, a $40 one will do if it has a 25 VAC scale or something. You put 1 vac of signal in with a FM radio on a rock station, then look for the beat on the pointer various places. Of course the volume pot will knock the AC voltage down some. Don't forget the .047 or .1 uf cap inseries with the negative probe on the AC scale, AC vom will false read on DC voltages without it. Also the pointer will kick when you try different places with different DC voltages on them. Or if you love *****, you can buy a scope. My used ones are broken, I don't recommend used scopes. "PC scopes" can be blown up by PA amps, the DC voltages exceed the voltage rating on the sound card. Most cheap scopes have an 80 v rating too, and CS800 can exceed that.
CS800x has only 3 voltage gain stages, U100, the U105, the VAS Q111 & Q113. Drivers & OT's are emitter followers, current boosters. U100 input can be squeezed down to nothing by the DDT Q110 jfet. Crams the input of U100 up to the plus 15 rail.
Note music can be lost on the input board in the 2.2 uf cap or the pot, or the 2.2 cap C147, check those with a Cmeter or do the cheapy route & just replace them, they cost $.10. The VI limiter Q105 Q116 can take the drive off the drivers by shorting it to speaker ground. Be suspicious of the .1 uf caps sprinkled around, they are 50 v rated and a rail voltage out the bass line of the OT's can open or short some of them. Same 50v rating on the .015 uf caps C128 C134, I had one of them bad (in my PV-1.3k) So shorted parts in the VI limiter circuit can take drive current off the driver.
By the the signal gets to the driver it should be pretty close to 46 vac average. My cs800s has 260 w rms 8 ohm, 8*260=2080, sqrt is 45.6. I think cs800x should be the same.
Note again, cheap digital DVM lie a lot about music. They are 50/60 hz. RMS digital VOM cost $180, still average over 2 seconds or so that will miss pulses, and won't even show 7000 hz up, so they will miss ultrasonic oscillation. Waste of money, IMHO. I did a lot of good diagnosis with a $25 R**** S**** meter, but they have gone to ****, so has Sears. Now I have a Simpson 266XLPM, but you don't need to spend $300 to get a 25 VAC scale 5000 ohms/V.
CS800x has only 3 voltage gain stages, U100, the U105, the VAS Q111 & Q113. Drivers & OT's are emitter followers, current boosters. U100 input can be squeezed down to nothing by the DDT Q110 jfet. Crams the input of U100 up to the plus 15 rail.
Note music can be lost on the input board in the 2.2 uf cap or the pot, or the 2.2 cap C147, check those with a Cmeter or do the cheapy route & just replace them, they cost $.10. The VI limiter Q105 Q116 can take the drive off the drivers by shorting it to speaker ground. Be suspicious of the .1 uf caps sprinkled around, they are 50 v rated and a rail voltage out the bass line of the OT's can open or short some of them. Same 50v rating on the .015 uf caps C128 C134, I had one of them bad (in my PV-1.3k) So shorted parts in the VI limiter circuit can take drive current off the driver.
By the the signal gets to the driver it should be pretty close to 46 vac average. My cs800s has 260 w rms 8 ohm, 8*260=2080, sqrt is 45.6. I think cs800x should be the same.
Note again, cheap digital DVM lie a lot about music. They are 50/60 hz. RMS digital VOM cost $180, still average over 2 seconds or so that will miss pulses, and won't even show 7000 hz up, so they will miss ultrasonic oscillation. Waste of money, IMHO. I did a lot of good diagnosis with a $25 R**** S**** meter, but they have gone to ****, so has Sears. Now I have a Simpson 266XLPM, but you don't need to spend $300 to get a 25 VAC scale 5000 ohms/V.
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thanks for the info.I dont have an analog meter yet.Jus hzve to look again for one.All were too high priced.
The relay clicking quit .now theres no sound but i found an mps 8097 is open.So i need to find a substitute.I have a bunch of those 0.22 100v caps coming because thats what mine uses.I think im gonna need to replace some more small transistors on driver board.
Bad mps8097 open so far but i got tired of looking at it for now.Ive got to do more studying.And yea i need an analog meter.
I meant to say it was playing and had full volume but the relay would kick when i turned it up loud..And ddt light would come on.Now nothing gets through and ddt is steady on.Now i found an open mps8097 npn..But now what caused the 8097 to go open.Further analysis i gotta do or learn to do lol.
Any present known replacement for mps8097?
ill be looking too at data x ref.Thanks for the input.My amp has no output.Not yet anyway.
The relay clicking quit .now theres no sound but i found an mps 8097 is open.So i need to find a substitute.I have a bunch of those 0.22 100v caps coming because thats what mine uses.I think im gonna need to replace some more small transistors on driver board.
Bad mps8097 open so far but i got tired of looking at it for now.Ive got to do more studying.And yea i need an analog meter.
I meant to say it was playing and had full volume but the relay would kick when i turned it up loud..And ddt light would come on.Now nothing gets through and ddt is steady on.Now i found an open mps8097 npn..But now what caused the 8097 to go open.Further analysis i gotta do or learn to do lol.
Any present known replacement for mps8097?
ill be looking too at data x ref.Thanks for the input.My amp has no output.Not yet anyway.
They are not picky. MPSA06/56 should replace MPS8097, also 2n5401/5551. Pick your polarity as appropriate. You can download the datasheet from datasheetcatalog, but Peavey tends to like ebc TO92 transistors. Any transistor will blow when BE junction gets >7v backwards. Also higher than rated CE voltage can blow one.
Relay should click when DC occurs, check C136,R177 c136 is the classsic Peavey DC detector. Also Q121 the sbs14 should drop 8 v when energized with a 12 v power supply through a 47k resistor.
I like test equipment from newark & parts-express but I don't think either one messes with analog voltmeter anymore. This one from e-bay for $25 seems about right, 8000 ohms/v on AC scales of 50 vac and 10 vac. Tekpower TP8260L Analog Multimeter With Back Light, and Transistor Checking dock 689790658945 | eBay
No experience with that brand. But E-bay, if it is not as described you can send it back in 30 days. Check it first thing with alligator clip leads and FM radio into RCA connector, earphone jack should put out up to 7 vac. You should see the beat of the drum of rock music into the pointer unless they have made a digital dual slope averaging circuit DVM circuit drive an analog pointer. Which would be useless.
Watch out for shipping from ***** on e-bay, express methods can run into $100's and surface mail can take weeks. It is better to look down the list for a similar higher priced item from a domestic vendor usually. But some items are not available domestically. That particular one was california it said.
Relay should click when DC occurs, check C136,R177 c136 is the classsic Peavey DC detector. Also Q121 the sbs14 should drop 8 v when energized with a 12 v power supply through a 47k resistor.
I like test equipment from newark & parts-express but I don't think either one messes with analog voltmeter anymore. This one from e-bay for $25 seems about right, 8000 ohms/v on AC scales of 50 vac and 10 vac. Tekpower TP8260L Analog Multimeter With Back Light, and Transistor Checking dock 689790658945 | eBay
No experience with that brand. But E-bay, if it is not as described you can send it back in 30 days. Check it first thing with alligator clip leads and FM radio into RCA connector, earphone jack should put out up to 7 vac. You should see the beat of the drum of rock music into the pointer unless they have made a digital dual slope averaging circuit DVM circuit drive an analog pointer. Which would be useless.
Watch out for shipping from ***** on e-bay, express methods can run into $100's and surface mail can take weeks. It is better to look down the list for a similar higher priced item from a domestic vendor usually. But some items are not available domestically. That particular one was california it said.
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I don't see any MPS8097 on the driver board parts list. Look at the picture of the board to find out the Q#, look on the driver parts list page 4 to see what it is really supposed to be. Match or exceed Vceo, match case, match pinout, gain if if buy from newark I don't get any garbage gains. I tend to use newark selector table, put in package, put in >vceo I want, maybe collector current min/max if I'm doing power transistors. Click stock only and no UK items at $20 a line item. Then push view and see what is cheap. There is usually something I can use at $2.50 to $8 a hundred. Preferred # like 2n5401/5551 tend to be $35 a hundred, I don't buy large quantities of those. Don't go double the Vceo there are noise and gain penalties. Like MPSA42/92, can work but noisy.
Watch out for NTE you pay freight on each item on those. Also NTE newjersey semi, central semi leaves out all the specs on the datasheet. On, Fairchild, ST Sanken Allegro are real mostly specified parts.
Watch out for NTE you pay freight on each item on those. Also NTE newjersey semi, central semi leaves out all the specs on the datasheet. On, Fairchild, ST Sanken Allegro are real mostly specified parts.
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