I'm trying to fix this amp that has blown outputs on the left side so I may as well replace the lot, is there any cheap but good T03 outputs I can use instead of chasing up these originals? Ive notice the CS-800 (89 series) comes in different flavors? Mine was shipped on 28/8/1991. SN# 00-05162993.
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MJ15024 and MJ15025 are the Peavey suggested replacements for 70484200 and 70474200. MJ21193 and MJ21194 are a little cheaper at farnell US, but you have to replace them all if you use those because the process is different.
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Mine are 70483180 & 70483180 is there any difference? The first 4 numbers are OK?
Search for the "Peavey semi-conductor cross reference", it will show you all of the generic numbers for just about all of Peavey's semis.
Craig
Craig
Using that document those cross to the same MJ numbers. The 180 refers to Vceo. There are other numbers in USA stock that have the Vceo or the current rating, but it is hard to find a safe operating area at 80 v that large. NTE has some with a soa rating, but they cost more. Out there in the Pacific, I would buy from a franchised distributor; it is pretty easy to wash off an old label and silk screen on a new one. I've got 2n6030 2n5630 from the junk box to work temporarily but I didn't really heat them up with a load before I replaced them. These were also old Motorola parts.
I had a lot of drivers, diodes, resistors, and 50 v ceramic capacitors blown up by the OT's. Also PWB traces. Check all pretty thoroughly before you remove the light bulb from the AC line. I had to put fuses in the OT base drive lines to stop explosions before I found a room heater element that would work. Don't use speakers, use 100w resistors for speakers until you are sure the DC is stamped out. 250 VAC residents find cooking appliances make good loads.
I had a lot of drivers, diodes, resistors, and 50 v ceramic capacitors blown up by the OT's. Also PWB traces. Check all pretty thoroughly before you remove the light bulb from the AC line. I had to put fuses in the OT base drive lines to stop explosions before I found a room heater element that would work. Don't use speakers, use 100w resistors for speakers until you are sure the DC is stamped out. 250 VAC residents find cooking appliances make good loads.
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Heating elements change resistance when heated..better use high watt metal clad resistors instead mounted to large heat sinks with fan cooling...
peavey cs800's the 70's model used all npn types in its o/p stage these being 140v 15 amp devices..
you need the check if your peavey is using npn and pnp types..use your working channel to check these devices...
regards..A
peavey cs800's the 70's model used all npn types in its o/p stage these being 140v 15 amp devices..
you need the check if your peavey is using npn and pnp types..use your working channel to check these devices...
regards..A
plus remove the triac from the o/p stage just in case its short circuited as this is the crow bar circuit.. it's main function is speaker protection that pull's the whole out to ground if there's large dc at the o/p and blows the primary mains fuse...the amplifier will work fine with out this small pcb in..
Water heater elements, when water cooled, will handle a LOT of power before their resistance changes. Even large metal cased resistors will double in value if you get them hot enough. And they're not as easy to water cool.
Any 1990's vintage PA amp that takes TO-3's ought to work with the MJ15024/5, as it was the best that was available at the time. Back in the 70's they had to use what they had - and cherry pick to get "enough" SOA. 140V-rated parts were commonly used up to 160V - and they just didn't run rails above that because it couldn't be made reliable. Now you can just go straight to the 21193/4/5/6 and call it good if you're buying new parts.
Early Peavey amps like the first CS800s used eithe RCA or Motorola transistors, but most of the run of CS800s used Motorolas. Do not mix the brands. (Thermal and current tracking problems if you do). All those SJ number and 704 numbers are peavey house numbers on Motoorola transistors.
SJ numbers came first, then at some point Peavy reorganized their part numbers. Now 704 means semiconductor, so all transistors of that era will have a 704 number.
PV used various moto types. More than one will cross to industry numbers. PV guide recommkends field replacement numbers, meaning what we can buy in the marketplace.
SJ6343 became 70483180, or MJ15024
SJ8306 came later, was also called 70484200, or MJ15024
and so on.
You will only find the 704 types at PV or a PV parts dealer. They are house labelled Motorola (On Semi) parts. SO I always just buy generic Moto parts in the market. MJ15024 is my go-to part for this.
The original 4-space CS800 did come in several revisions: A, B, and C. the C series also called the zener series sometimes. Then PV reengineered the series, and they shortened to a three-space rack chassis. The dominant spotting festure is the "wind tunnel" on the front. IN fact even the factory calls the later ones the wind tunnels. The older ones had a fan in the rear and vents along the sides of the top. The newer wind tunnel units have the large screen-covered air vent in the front panel near the volume controls. Your unit seems to predate the CS800X by a few years, but if yours is a wind tunnel, then use the CS800X schematic.
Oh another way. Old style amps have two power modules with heat sinks, pull the lid and there they are. The newer ones have a large board almost as big as the amp, one channel top, and the othe channel bottom, insteaf of left and right sides like the older. (Of course in Australia, the top and bottom ones are reversed.)
And amptech is certainly right. ANy time your outputs are blown, ALWAYS check that SAC187 triac by the speaker posts. It is a sacrificial part intended to keep your speakers from catching fire.
SJ numbers came first, then at some point Peavy reorganized their part numbers. Now 704 means semiconductor, so all transistors of that era will have a 704 number.
PV used various moto types. More than one will cross to industry numbers. PV guide recommkends field replacement numbers, meaning what we can buy in the marketplace.
SJ6343 became 70483180, or MJ15024
SJ8306 came later, was also called 70484200, or MJ15024
and so on.
You will only find the 704 types at PV or a PV parts dealer. They are house labelled Motorola (On Semi) parts. SO I always just buy generic Moto parts in the market. MJ15024 is my go-to part for this.
The original 4-space CS800 did come in several revisions: A, B, and C. the C series also called the zener series sometimes. Then PV reengineered the series, and they shortened to a three-space rack chassis. The dominant spotting festure is the "wind tunnel" on the front. IN fact even the factory calls the later ones the wind tunnels. The older ones had a fan in the rear and vents along the sides of the top. The newer wind tunnel units have the large screen-covered air vent in the front panel near the volume controls. Your unit seems to predate the CS800X by a few years, but if yours is a wind tunnel, then use the CS800X schematic.
Oh another way. Old style amps have two power modules with heat sinks, pull the lid and there they are. The newer ones have a large board almost as big as the amp, one channel top, and the othe channel bottom, insteaf of left and right sides like the older. (Of course in Australia, the top and bottom ones are reversed.)
And amptech is certainly right. ANy time your outputs are blown, ALWAYS check that SAC187 triac by the speaker posts. It is a sacrificial part intended to keep your speakers from catching fire.
Thanks Enzo, for adding more information regarding these reliable old amp's from peavey.. I've serviced many of these amps and once there put back into action they keep going for years..
Regards.A
Regards.A
Yes, indeed these are great old amps, they are well built and sturdy, well suited to the application, and when they do break, they are easy to service.
I'd rather fix 10 of these beasts than one Carver PM1.5 And the PM1.5 is a fine amp, but not as roadable and serviceable as a CS800.
I'd rather fix 10 of these beasts than one Carver PM1.5 And the PM1.5 is a fine amp, but not as roadable and serviceable as a CS800.
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