That comparator is defective. With those input voltages, pin 1 should be near 0v.
If you have to post any other voltages, don't use a '-' sign unless it's a negative voltage. Use a colon. It will help eliminate problems/mistakes.
If you have to post any other voltages, don't use a '-' sign unless it's a negative voltage. Use a colon. It will help eliminate problems/mistakes.
i found a replacement @ my local component store, but its a LM339DP does this make a difference?
I don't know what the P suffix indicates. It could mean that it's in a plastic case instead of ceramic (which would be OK). The LM339D is the right part number.
Have you ever replaced something like this?
Is it in a highly populated area?
Do you have any kapton tape?
Have you ever replaced something like this?
Is it in a highly populated area?
Do you have any kapton tape?
never have touched one of these before. i live really close to an electronic components store, i can get nearly anything i need from there. i don't have kapton tape(don't know what it is either lol), and yes highly populated with mostly smd resistors, and some other things.
whats the process for replacing this?
whats the process for replacing this?
also is there a chance that this ic went bad from another issue in the amp, so if i replace it, it might go bad again?
In a highly populated area of the board and no Kapton tape, try it this way:
Apply lots of extra solder to one row of pins. Run the iron back and forth over that row until the solder on all pins is molten. Continue heating the solder and 'gently' lift up on that side of the IC (from the end) with a small screwdriver. Lift until the IC is at a 10-20° angle. Be VERY careful not to cut any traces with the screwdriver. Use desoldering braid to remove the solder from that row of pins (slide the braid between the pins and the pads). Flux will help the solder flow into the braid. When the solder has been removed and all of the pins on that side are free, add solder to the other row of pins and heat until the solder is molten. Slide the IC so that row of pins moves into the area that was under the IC (where there are no other components). Remove the IC and desolder all pads completely.
Add solder to one of the corner pads (preferably the one with the most copper for the trace/pad). Heat the solder and slide the IC into place. Solder the opposite corner. If the IC is in the correct position, solder the other pins. If you bridge two or more pins, remove it with the braid.
Be absolutely sure that you don't heat adjacent components by making contact with the with the braid, the solder or the iron.
Apply lots of extra solder to one row of pins. Run the iron back and forth over that row until the solder on all pins is molten. Continue heating the solder and 'gently' lift up on that side of the IC (from the end) with a small screwdriver. Lift until the IC is at a 10-20° angle. Be VERY careful not to cut any traces with the screwdriver. Use desoldering braid to remove the solder from that row of pins (slide the braid between the pins and the pads). Flux will help the solder flow into the braid. When the solder has been removed and all of the pins on that side are free, add solder to the other row of pins and heat until the solder is molten. Slide the IC so that row of pins moves into the area that was under the IC (where there are no other components). Remove the IC and desolder all pads completely.
Add solder to one of the corner pads (preferably the one with the most copper for the trace/pad). Heat the solder and slide the IC into place. Solder the opposite corner. If the IC is in the correct position, solder the other pins. If you bridge two or more pins, remove it with the braid.
Be absolutely sure that you don't heat adjacent components by making contact with the with the braid, the solder or the iron.
Yes. It could fail again (although it's unlikely). That's why I suggested that you order extras.
figured out the difference between the part numbers. ones a larger though hole design, no surface mount. figures that out once i got home with 3 of them.
this is what im going to order, maybe 10, is there anything else i should order, just in case this part is not what causing the problem, but more or less a result of another problem?
LM339D STMicroelectronics Comparator ICs
LM339D STMicroelectronics Comparator ICs
Those should be the right ones.
I don't have any suggestions for other parts.
If you don't have desoldering braid, order some (with flux). This one should work well:
577-1804-10F
I don't have any suggestions for other parts.
If you don't have desoldering braid, order some (with flux). This one should work well:
577-1804-10F
alright ordered that braid and parts, thanks for the heads up. will be in tomorrow, so well see whats happens. i ordered five ic's
alright, replaced the ic @U3, triple checked for solder bridges.
problem is, still have blinking protect light. the squeak sound is more evident now than before.
dunno what to do next. also with fused removed and applying remote power, get a slight lighting of both thermal and protect LED's.
tried to power up with 15 amp fuse, it blew as soon as power was applied. tried 30 amp, didnt blow, but got the flashing protect.
does other ic need replacing? if not whats next to test etc?
problem is, still have blinking protect light. the squeak sound is more evident now than before.
dunno what to do next. also with fused removed and applying remote power, get a slight lighting of both thermal and protect LED's.
tried to power up with 15 amp fuse, it blew as soon as power was applied. tried 30 amp, didnt blow, but got the flashing protect.
does other ic need replacing? if not whats next to test etc?
alright, first voltages aren't flashing anymore. and led blinkes 2 times per flash instead of one.
ic U3
pin 1/4.7
pin2/4.7
pin 3/4.9
ic U3
pin 1/4.7
pin2/4.7
pin 3/4.9
I don't know if anything else has changed but the output agrees with the input now. It previously did not.
Is the voltage the same as the last time you posted the voltage on this IC? If not, repost the voltages. Copy and paste the following list.
U3
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Is the voltage the same as the last time you posted the voltage on this IC? If not, repost the voltages. Copy and paste the following list.
U3
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
- Status
- Not open for further replies.