I have recently bought a peavey cs400x off ebay.... worked fine, a cracking amp... love it... did a 12 hour gig at full power, only got a touch warm... but switched it on a few days ago and channel a is down... anyone else experienced this? or can point me in a good direction? channel b still works.. and the soft start relay on channel a does not click on powerup... ??
Once had a CS800 and CS1200 (not X) and the CS1200 ceased to function in similar circumstances as you... The solution : changing output transistors....
However, the CS800 never had any problem while being driven @ 100% for 4 years. When I sold it, it wasn't giving its original power output but no components has ever failed.
good luck
However, the CS800 never had any problem while being driven @ 100% for 4 years. When I sold it, it wasn't giving its original power output but no components has ever failed.
good luck
Check the Bridge/Stereo switch on the back.led_zeppelin said:
Make sure you tighten (not too hard) all the screws of the output transistors. You’ll need a Torx screwdriver.
It's a bit of a hassle to dismantle the amp.
Here's how it works: Remove the top panel.
Remove the front panel and the two volume knobs. Careful with the knobs screws, they break. Remove all the screws from the front behind the front panel including the two small silver coloured ones.
Remove the screws at the backside located on the outer sides.
Remove the two bigger screws top left and top right on the backside and the same two that hold the bridge rectifier. (Not sure about that bridge here, could be for CS800.)
Remove the screws on the side panels near the back.
You should be able to pull the complete PCB plus back panel without the power supply.
Does the Ch. A DDT led light up constantly, only when a small signal is applied or never?
Does the Ch. A Power LED light up?
/Hugo
yeah, neither the ddt or powerlight come on for channel a... thats what led me to believe it was a power problem, rather than a semiconductor one... when i got it... he told me the relay on channel a stuck a little, but it clicked back in with a little bash, well it's been a 2 weeks and no joy.... it wasn't in use when it happened... thats why i dont think it was the o/p transistors... i just switched it on and it ceased to work... i thought the channel may have been disabled... but i don't know about the peavey safety circuitry....
Normally, the CS400X doesn't have the triac at the output.
Are the output transistors originals? Or is it a mix from different types, production numbers? They should all be 71140/ 81140 for the drivers and 74140/84140 for the outputs.
Now, did you check the Bridge/Stereo switch at the back?
Move the switch a few times or if you never will use the amp in bridged mode, bypass it.
/Hugo
Are the output transistors originals? Or is it a mix from different types, production numbers? They should all be 71140/ 81140 for the drivers and 74140/84140 for the outputs.
Now, did you check the Bridge/Stereo switch at the back?
Move the switch a few times or if you never will use the amp in bridged mode, bypass it.
/Hugo
he's saying...check the obvious first..then report back to his foum...we'll help you along the way...but if you dun check it...how can we help??...sometimes easy things are overlooked..maybe the LED was loose?? Have you actually checked to make sure the channel is actually off?? the LED not lighting up...doesn't mean the channel is out...
yup... i've tried the channel eventhough the led's are off... and i've had a poke at the relay, as if it was just sticking, a little tap should help... but no joy... there doesnt appear to be any obvious melted or burned components, but i haven't had time to get the whole board out yet... i've tried all switches.... and none are causing the fault , unless one is malfunctioning... i've checked all connectors, as they can often go dry... no luck and i've tried different inputs/outputs/bridge configuration.... no luck.
Ok, first thing to do now is tighten the screws and measure all output transistors. You can easily compare with the good working channel.
On one of the output transistors there's a thermal breaker mounted. Compare it with the good channel.
Look for bad solder joints while you're at it. Quite unlikely, the Peavey's have good boards and soldering, but one never knows.
Also, in between the power transistors there are four small diodes isolated with plastic tubes. Check them.
If all is fine, go to the small signal board and replace TL072.
/Hugo - has some more info if all that is checked (but not much)
On one of the output transistors there's a thermal breaker mounted. Compare it with the good channel.
Look for bad solder joints while you're at it. Quite unlikely, the Peavey's have good boards and soldering, but one never knows.
Also, in between the power transistors there are four small diodes isolated with plastic tubes. Check them.
If all is fine, go to the small signal board and replace TL072.
/Hugo - has some more info if all that is checked (but not much)
Hi li,li_gangyi said:
The relay is the output relay, not the soft start. There is no relay in the power supply. If one channel works, both channels get the main supply power, which is +/-52V.
There is the possibility that the output relay is broken but I never encountered that problem.
I’m not sure this could cause the power LED not the lit.
/Hugo
When the thermal breaker mounted on the output transistor is active or broken, the +15V is disabled as part of the protection circuit.
Besides feeding all opamps, the +15 also serves the On-LED and the output relay. So if the protection is activated for some reason, the LED’s and relay won't work.
Are you also talking about a CS400?
Hugo
Besides feeding all opamps, the +15 also serves the On-LED and the output relay. So if the protection is activated for some reason, the LED’s and relay won't work.
Are you also talking about a CS400?
Hugo
problem with the relay... as it does not click on... its a black one tho, so you cant see thru... this makes me un sure as to if its the relay, or the protection circuitry that control's the relay.... because if it was 'stuck', then the bash should help... and the bloke i bought it off said he had that problem before.... but no joy... when i get home i'll try to check the transistor bolts... and the thermal switches... but shouldn't they automatically reset anyway?
hmmm...might be a real possibility...or maybe if the opamp was powered from a zener..which I assume to be the case..or a linear regulator..have it checked out..and it's de-coupling caps as well...I dun really have this amp..and No...I wasn't referring to this amp when I mentioned the broken relay...
Measure the relay contacts for any continuity when it's supposed to click...if in dpoubt throw it out~!! Have it repaleced...for a crude test...use a wire and link up the part...should give you the same thing..but of course without the protection and stuff..which will cause turn-on turn-off thumps...if it works ok after you use a wire link...have the relay replaced...
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