I have a Crown CE4000 looks like it’s in very good condition no corrosion and very very little dust but it has a couple of blown components, board reference U13 which is a surface mount ic but half the top is blown off where the numbers are, looks like a LM393 which I can see other LM393 chips around there so I assume U13 is the same.
And also board refence U2 which is a VIPer100A located on that offshoot board in the power supply section and that component is blown in half.
All other components look fine.
Would it most likely be just those 2 components? Or does this model have a common fault or something? Is it worth replacing just those 2 components and powering it up? Or is that too risky?
Cheers
And also board refence U2 which is a VIPer100A located on that offshoot board in the power supply section and that component is blown in half.
All other components look fine.
Would it most likely be just those 2 components? Or does this model have a common fault or something? Is it worth replacing just those 2 components and powering it up? Or is that too risky?
Cheers
I would for sure think more components are blown, especially in the output section .... but who knows.
You'll probably need a service manual / schematic to track down what might have blown.
LM393 is a dual comparator ... for it to blow in half something else must have caused it.
Viper100 i a low current SMPS IC, probably used for some input circuit or maybe for the gate drive voltage .... again you need to consult with a schematics.
As I recall it is a multi-stage class d construction, so fairly complex.
Not to take the spirit from you, but to fix this amp I think you need to know what you are doing.
But I would for sure think it is worth restoring ... quite a well built amp
You'll probably need a service manual / schematic to track down what might have blown.
LM393 is a dual comparator ... for it to blow in half something else must have caused it.
Viper100 i a low current SMPS IC, probably used for some input circuit or maybe for the gate drive voltage .... again you need to consult with a schematics.
As I recall it is a multi-stage class d construction, so fairly complex.
Not to take the spirit from you, but to fix this amp I think you need to know what you are doing.
But I would for sure think it is worth restoring ... quite a well built amp
Quick search on the web:
CROWN CE4000 SCH Service Manual download, schematics, eeprom, repair info for electronics experts
... Viper used for low voltage supplies
.... I see a LM393 used for current sensing ....
.......
CROWN CE4000 SCH Service Manual download, schematics, eeprom, repair info for electronics experts
... Viper used for low voltage supplies
.... I see a LM393 used for current sensing ....
.......
Switcher supplies with blown up components, I haven't had much luck with. Did okay with a blown fuse and a blown NTCR used as a fuse, both caused by leaky filter caps. But down in the switching area, good luck. I'm 0 for 3 with those. Also probing around the 200 VDC 240 vac area is intensely dangerous, and they don't respond well to a light bulb box energy limiter. Follow the one hand at a time rule, don't wear jewelry on hands or neck. wear safety glasses cover off power on, exploding components can damage your eyes. You better have a scope and a LCR meter and just because those C & L components read okay at 2 v test voltage doesn't mean they don't short at 100 or 200 v. At least you can get a schematic diagram on this, the 3 computer monitors I tried to fix didn't have one. Should have been simple, they all worked sort of a few minutes when first turned on. Put in some new e-caps and they sit there dead.
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U13 is the protect line. These, in my experience, only fail if the + - 15volt standby supply goes high, if that has happened, most of the op amps that are fed from that line will be suspect.
U2 is the chopper stage for the standby power supply. When replacing it, ensure you replace the tuning components; C5, R5, U3 and U4.
There are no high current paths around U13 and every input / output pin has a feed resistor.
Very odd fault for a very reliable machine.
U2 is the chopper stage for the standby power supply. When replacing it, ensure you replace the tuning components; C5, R5, U3 and U4.
There are no high current paths around U13 and every input / output pin has a feed resistor.
Very odd fault for a very reliable machine.
It uses a PFC so you'll have 400Vdc on the primary side ..... so yes don't do it unless you know exactly what you are doing .....
It's a big amp with a big supply and it can for sure kill you ....
It's a big amp with a big supply and it can for sure kill you ....
When you have replaced the faulty components, place an 18volt supply between the cathode of D5 (positive) and SMPS Ref pin 4 of the 'Viper' chip. It should run and oscillate at about 80k Hz.
If OK, wear protective eye glasses and be careful when powering it up. If it doesn't go bang, you are very lucky and can proceed to the next step of testing it.
Watch yourself, there are lethal voltages in there!
If OK, wear protective eye glasses and be careful when powering it up. If it doesn't go bang, you are very lucky and can proceed to the next step of testing it.
Watch yourself, there are lethal voltages in there!