TFM5380 vs TSOP1738
 

Just sharing an experience.
Got this Harman/Kardan AVR20 MkII receiver amp for repair with a no
remote operation complaint. Tested the remote control on my remote
tester( the plug in the wall type that shrieks when IR hits it) and it
seemed fine. Opened the amp looked for a signal at the 3 legged IR
receiver's output pin (TFM5380) and found none. Inquired and hunted in
the local market and i couldnt find it. Checked the datasheet and it's
specs seemed almost identical to those of TSOP1738, with one
exception;
TSOP1738 features mentioned "Suitable burst length .10 cycles/burst"
while TFM5380 datasheet stated "Continuous transmission possible
(tpi/T
0.4)"
I decided to try the TSOP1738. The remote would work but
intermittently. I desoldered all microswitches in the microcontrollers
(CXP50116) key matrix thinking some leakage in one or more of the
switches might be mis-interpretted as a key being pressed which might
have priority over IR input. No change. Forced the External Interrupt
pin of the microcontroller low (active high), still worked errantly.My
heart sank, damn, could it be the microcontroller itself? Where'd i get
one with the same suffix CXP50116-652. Went back to the market and
hunted for an alternative to TSOP1738. This shopkeeper had one in the
same package without any number printed or etched into it. Bought it,
soldered it in place and the unit works FINE. Tested it over distance
too. He, the shopkeeper, said he'd got feedback from several
technicians that it worked like a breeze.
So, was the remote command string longer than 10 cycles/burst?????
Jango