Crown CE1000 amp repair suggestions?

[Repairfreak]

Hello, does anybody have experience with repair of Crown CE1000 amp. Have one in for repair. Had blown outputs (one channel), and their emitter resistors on this channel, and blown parts in bias servo section. Many many small smd chip components on this double sided mainboard. I’m just hoping there aren’t parts blown elsewhere that I may be overlooking. Where I’ve found failure I’ve focused, tested and replaced all associated parts, done comparison with good channel for resistances, capacitors, etc. Any successful repair history of this amp for sharing would be greatly appreciated. Amp was turned on at full input and full volume and now is faulting. Inspection on bottom of mainboard reviled many blown .4 ohm 1W SMD power output emitter resistors. All of the emitter resistors were changed out along with shorted Output Transistors found only on chan #1
Other parts found shorted or bad were Q111 MMBT5087LT1, Q110, Q120, Q104 2N3904 therm sense,R150, R133, Q114, Q115, Q118
Other parts in damaged area and replaced anyways were: C135,C115, R146, R147
Others checked and/or compared to other channel
L100, R148, R145 and bias adjust trimmers R134, R234, all SMD 1n914 diodes in these sections checked as well as other smd q’s, as well as U106 LM234 TO92 size volt reg.

T.I.A.

Mike

[The Dude]

At the risk of sounding like a "guru" that used to hang out here: Not at all a dig on you repairing the amp, but I'll say this. I don't fix the Crown CE line in my shop. They usually need a ton of parts, and repair is very labor intensive and frustrating. That, coupled with the fact that you can buy a working used CE1000 for between $100-$200, makes attempting to repair them uneconomical.

[Jazz P Bass]

A lot of effort to get them apart fully.

SMD heaven. (or Hell)

Be aware that to run the amp out of the enclosure you have to jumper circuit points that are normally connected through the chassis when bolted down.

[Repairfreak]

Hello Jazz P Bass, and The Dude
Yes, I here what you are saying. This is a challenging repair dealing with 0805 size smd’s etc. Luckily I have the tools and patience to replace these micro sized parts. Doesn't help either that the Crown schematic is chopped up into many segments which breaks the continuity of following the circuit. Besides the dealing with this and the size of the parts is the frustration of trying to test some of these SMD in circuit. As anyone with experience knows many times other parts tied into the one desired to be tested interfere with the measurement. Unlike through hole components where you can simply lift one leg and then test, with these SMD components they cannot withstand repeated heatings with iron without risk of damage. So it has been my job to compare suspected components with the other good channel. Otherwise I would be replacing all day and night these SMD that test strange because of other soldered in series or paralleled parts. Hopefully I can get at least one of these amps fixed for my customer, but might turn away the second. For it is as said, it is very difficult dealing with this board. I will not be testing without board fully installed, and yes it takes some time to put everything back together. Not a service friendly design at all.
There has been times in past where I have cut the bottom of a chassis out just to make a service access door, quite ridiculous to not have such built into the design. But yes, I guess this is what you get for a economy priced amp which some would just throw away.

Mike

[The Dude]

I'm not a person who likes to turn away a repair. Nor do I like being a Negative Nancy. But, it's just the way these amps are- not repair friendly and cheap. Even if you could fix it in 1 hour, add parts and you'r already at or above the cost of a replacement. And, who can fix one of these in just 1 hour? You just have to face the fact that not everything is worth fixing. I do wish you luck!

[Enzo]

That is one thing I teach techs - it is OK to decline repairs.