Hi all!
I have a Crown CE4000 amplifier. It had worked with no issues until one day we decided to open it up and blow any dust out of it. After doing this, it will work fine for 3-5 minutes, then it will fault. Letting it sit for a couple of minutes, it will then work for a couple of minutes again. If I had a guess, I would say its an overheating issue. Everything seems to be intact, and the fan works.
I just found this forum, so figured I would see if anyone has any ideas before I take it to a repair shop. Thanks in advance!
I have a Crown CE4000 amplifier. It had worked with no issues until one day we decided to open it up and blow any dust out of it. After doing this, it will work fine for 3-5 minutes, then it will fault. Letting it sit for a couple of minutes, it will then work for a couple of minutes again. If I had a guess, I would say its an overheating issue. Everything seems to be intact, and the fan works.
I just found this forum, so figured I would see if anyone has any ideas before I take it to a repair shop. Thanks in advance!
I've been nosing around the search engines, and the schematic for this that is available from elektrotanya is very complex. The actual 146 page service manual requires registration on a site I don't choose to give my e-mail address, and the official version is being sold by Crown. There are pages of schematic from the search engine that may refer to several different amps, so which one is yours would require some experience to determine. Furthermore the schematics are partial with mysterious connectors in and out without a lot of sense where they go or what they do. The page I've got has an op amp section and 14 transistors just to drive one channel of a headphone, without any sense as to where the main driver channels are.
I don't see any obvious static sensitive components in there, which could be damaged by blowing air on them. I'd say give this one a rest and try to learn amp repair on something simpler from a company that gives away their schematics. +-45 v rails are pretty high energy anyway to be learning amp repair on, too.
If you do decide to have at it. buy the service manual. You'll also need a DVM, an analog VOM or oscilloscope, some alligator clip test leads to keep your second hand out of there, a grabber test lead for looking at DIP pins without blowing up the IC, and a light bulb box to limit the energy going to the amp. The later is usually built oneself, using a socket and a 60 or 100 W light bulb in series with the AC coming from the wall socket and going to the amp. I build this in a grounded box with a circuit breaker, so if the wires come unscrewed and fly around, which is likely with screw terminals, there is no danger of your body coming in contact with unlimited energy.
I got a PV-1.3k going, that was complex enough and the Peavey schematics are complete enough to be useful to tyros like me. Also their schematics include industry part #'s for the IC's, which does not seem to be the case for the Crown. More page turning required to cross IC number to parts list number.
Best of luck finding an honest repairman. Thre are a couple that contribute to this forum, but there a lot of sleazy ones out there proved by the used electronic devices I've bought or salvaged. From the TV's I've found on the curb for the garbage man around here, "servicemen" are prone to splice in used capacitors parallel to failing ones, up in the air so they don't have to take the board out. You've got to take an old e-cap out to prevent shorts in the future. One "serviceman" had the gall to initial & date the board after he replaced a failed capacitor in a 1998 build amp with a capacitor with a production date of 1986. Of course that 1986 one was failed again just a few years later. Electrolytic capacitors deteriorate on the shelf or in the circuit, IMHO, just like tires, due to the rubber seal. Except the exceedingly rare epoxy sealed ones. When you go into an electronic device over 10 years old, better commit to replacing every electrolytic or tantalum cap with a fresh part produced recently at the end of the job, or expect the amp to fail every few months as the other old e-caps fail one by one. Like those TV's left on the curb for the garbage man. No I didn't keep the salvage e-capacitors, just the heat sinks and a few transistors diodes resistors & film capacitors.
I don't see any obvious static sensitive components in there, which could be damaged by blowing air on them. I'd say give this one a rest and try to learn amp repair on something simpler from a company that gives away their schematics. +-45 v rails are pretty high energy anyway to be learning amp repair on, too.
If you do decide to have at it. buy the service manual. You'll also need a DVM, an analog VOM or oscilloscope, some alligator clip test leads to keep your second hand out of there, a grabber test lead for looking at DIP pins without blowing up the IC, and a light bulb box to limit the energy going to the amp. The later is usually built oneself, using a socket and a 60 or 100 W light bulb in series with the AC coming from the wall socket and going to the amp. I build this in a grounded box with a circuit breaker, so if the wires come unscrewed and fly around, which is likely with screw terminals, there is no danger of your body coming in contact with unlimited energy.
I got a PV-1.3k going, that was complex enough and the Peavey schematics are complete enough to be useful to tyros like me. Also their schematics include industry part #'s for the IC's, which does not seem to be the case for the Crown. More page turning required to cross IC number to parts list number.
Best of luck finding an honest repairman. Thre are a couple that contribute to this forum, but there a lot of sleazy ones out there proved by the used electronic devices I've bought or salvaged. From the TV's I've found on the curb for the garbage man around here, "servicemen" are prone to splice in used capacitors parallel to failing ones, up in the air so they don't have to take the board out. You've got to take an old e-cap out to prevent shorts in the future. One "serviceman" had the gall to initial & date the board after he replaced a failed capacitor in a 1998 build amp with a capacitor with a production date of 1986. Of course that 1986 one was failed again just a few years later. Electrolytic capacitors deteriorate on the shelf or in the circuit, IMHO, just like tires, due to the rubber seal. Except the exceedingly rare epoxy sealed ones. When you go into an electronic device over 10 years old, better commit to replacing every electrolytic or tantalum cap with a fresh part produced recently at the end of the job, or expect the amp to fail every few months as the other old e-caps fail one by one. Like those TV's left on the curb for the garbage man. No I didn't keep the salvage e-capacitors, just the heat sinks and a few transistors diodes resistors & film capacitors.
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I would check for cold solder joints or bad connections first.
Spade connectors tend to be loose.
Spade connectors tend to be loose.
no thermal switch to be found in a CE4000 it a rather complex design employing PWM supplies that incorporate current monitoring and thermal sense for fault protection.
so the repair shop you take it to better have their pants pulled up...and the right tooling to deal with SM components.
high pressure compressed air is not a good way to clean electronics as it can force dirt into places it should not be as well as damage small components.(been down that road before!)
so the repair shop you take it to better have their pants pulled up...and the right tooling to deal with SM components.
high pressure compressed air is not a good way to clean electronics as it can force dirt into places it should not be as well as damage small components.(been down that road before!)
Do not run it for more than 5 minutes without the cover on as the airflow and therefore cooling is stopped and it will overheat!
There is no thermal switch, it is within the design, using temperature sensors on the boards and they talk to the control panel.
There is no thermal switch, it is within the design, using temperature sensors on the boards and they talk to the control panel.
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