ISC isn’t as good. Their copies aren’t much better than outright fakes. Construction is particularly crappy. I’ve never tried MJ15025’s from any of the “regular” second sources (Mospec, Central, Multicomp), but their copies of obsolete parts have been “okay”. Not necessarily up to the capabilities of the originals but seem to meet “spec”. Real ON parts (and obsolete Motorola’s) often exceed the spec with wide margins. You can’t count on even a *good* second source to do that. Especially not with something like a 15025.
You’re really supposed to replace an entire bank of parallel outputs if you blow *one*. If you are dead set on replacing only the one, use a genuine ON for sure.
You’re really supposed to replace an entire bank of parallel outputs if you blow *one*. If you are dead set on replacing only the one, use a genuine ON for sure.
For the PTC, I’d have to go digging around in the catalogs to find something appropriate. PTC10 suggests a 10 amp current rating. Likely to be fairly common.
Check to make sure that’s not the only blown transistor. The driver for that bank, and associated resistors, may have suffered collateral damage. Almost always does.
Check to make sure that’s not the only blown transistor. The driver for that bank, and associated resistors, may have suffered collateral damage. Almost always does.
If XLS802 produces 800 W on speakers, likely draws 1600 w or 12.8A on 125 vac. GE MOV CL-11 is for 12 A steady state, .7 ohm cold resistance. GE MOV CL-101 is 16 A steady state, .5 ohm cold resistance. As long as thermistor is in series with input of transformer, chose similar parameters on other brands. If Mains fuse on amp is lower than 12 amps, choose thermistor suitable for that steady state current. As GE CL-21 is 8 amps steady state, 1.3 ohms cold resistance.
You may want to look into the cause for the PTC burning.
The two PTCs together with the 47 ohms/23W are used to limit the inrush current during power up.
After a short delay, the power relay is activated, thus shorting out these resistors.
Since the PTC is damaged, it indicates that the power relay is opened when the amp goes into protect mode. This should not be the case.
Regards
Mike
The two PTCs together with the 47 ohms/23W are used to limit the inrush current during power up.
After a short delay, the power relay is activated, thus shorting out these resistors.
Since the PTC is damaged, it indicates that the power relay is opened when the amp goes into protect mode. This should not be the case.
Regards
Mike
Yeah, there was just a lot of current when the amp failed. What these amps and others like them NEED is a way to sense excessive temperature rise in the PTC and just enter a permanent shutdown mode when something bad happens. Crown used to make extensive protection circuits, but more modern stuff has been severely lacking in that department.