the first series of this amp(99-01/2) board rev.A, mfg 03/2000. anyways r51 and r52 are toast. they should be the same. also, would be nice to know the part number for d51, and d53. on a side note, would be curious if anyone knows what goes in u108/u109, as they are ground at the factory, but i think they are fine....... thanks,
-Heath H-
-Heath H-
here's the board. just figured out how to upload pics quicker. need better pics?
An externally hosted image should be here but it was not working when we last tested it.
Since I don't have anything specifically for this amp, I would need a relatively good photo of the area were the resistors are located.
best i can do right now. a couple of the pics didn't upload for some reason..... oh, there they went. moved the original, so i think i'll upload that one, too.
hmm, can't seem to make it upload in high res. should be at 2592*1944... i may see if i can find the time to pop open the 750d, and 1100d and try to match up the circuit. thanks.
It looks like the Memphis circuit. The resistors are 22 ohms.
The 16 pin IC is an MC14060. The 14 pin IC is an LM361.
The service manual for the JBL BP1200.1 has schematic diagrams that are very close to many parts of this amp.
The 16 pin IC is an MC14060. The 14 pin IC is an LM361.
The service manual for the JBL BP1200.1 has schematic diagrams that are very close to many parts of this amp.
here is service manual for jbl bp 1200.1
JBL BP1200.1 SM Service Manual free download, schematics, eeprom, repair info for electronics
JBL BP1200.1 SM Service Manual free download, schematics, eeprom, repair info for electronics
thank you guys. so, i'm assuming this is the rectifier circuit for the ic/etc regulators, as it shows in the bp1200 schematic. if that is the case, i am going on the assumption that these both had to have failed at the same time for whatever reason, i.e. freeze, and shorted. it's just weird that both sides of the circuit have the heat damage equally, from running the higher current, but only the one cap seems definitely blown. i just don't want to miss something else that could have caused this.
i am just ordering parts at this point, but i will be replacing the 2 caps, 2 resistors, and the 4 diodes, even though just the 2 got hot. will also be replacing the rail caps, which i already have. did i miss anything?
the diodes read, from what i can tell:
FR154
DC
that number does not come up on digikey, but on the 1200bp schematic, it lists "PR1504" as the diodes used, and those do come up. should i use the pr1504's? is there a reference that shows how to decode the print into that number?.. oh wait, i just noticed that it is a non-stock item. is there a good part number that i can use?
the original complaint of this amp was that it just put out nothing but static, which kind of makes sense, not getting enough power to the regulators, and no filtering. all i have tested as of yet, are the winding and traces from the top-side and all appear well. i also did an ohm check on the regulators, which appeared okay.
thanks again for your help,
-Heath H-
i am just ordering parts at this point, but i will be replacing the 2 caps, 2 resistors, and the 4 diodes, even though just the 2 got hot. will also be replacing the rail caps, which i already have. did i miss anything?
the diodes read, from what i can tell:
FR154
DC
that number does not come up on digikey, but on the 1200bp schematic, it lists "PR1504" as the diodes used, and those do come up. should i use the pr1504's? is there a reference that shows how to decode the print into that number?.. oh wait, i just noticed that it is a non-stock item. is there a good part number that i can use?
the original complaint of this amp was that it just put out nothing but static, which kind of makes sense, not getting enough power to the regulators, and no filtering. all i have tested as of yet, are the winding and traces from the top-side and all appear well. i also did an ohm check on the regulators, which appeared okay.
thanks again for your help,
-Heath H-
Mouser has the originals but if you want to order from DK, the BYV28-200-TAPCT-ND is a good sub for this application. The BYV-28 is good for most instances where you need a fast efficient, relatively high-current diode in a small package. If the originals aren't defective, you don't need to replace them.
The electrolytic capacitors will likely need to be replaced. The FC series of capacitors is a good choice.
P10316-ND (check lead spacing)
If/when you replace the diodes/resistors, install them so that they're about 1/4" above the board. That will prevent them from doing further damage to the board. Using larger resistors will also reduce the operating temperature.
The electrolytic capacitors will likely need to be replaced. The FC series of capacitors is a good choice.
P10316-ND (check lead spacing)
If/when you replace the diodes/resistors, install them so that they're about 1/4" above the board. That will prevent them from doing further damage to the board. Using larger resistors will also reduce the operating temperature.
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