I think this is similar to problems ppia600 was having with similar amp in another post.
I have two planet audio TT2250d amplifiers having similar problems. On the output I get a triangle wave from 1-1.5v P-P. Fan not turning so checked driver Board and MPSA42 gets hot and I replaced with MPSW42, didn't change so I replaced all 4, still no change. With all 4 MPSW42 removed the MPSA56 get hot now, wave is gone on output. New MPSW42 into amp get hot and wave is back.
Power and output Fets good, removed inductors to check for shorts, wasn't sure if it shorted but I wedged wire over so it wouldn't in future, no change. One of the amps had one output cap blown off the board, replaced all 4, and checked inductors.
Rail voltage is +/-69.5
+/- 15 volts is ok
On the driver board is an IC that has number sanded off not sure if that is bad or what values should be.
Power IC values appear good.
All test with RCA unhooked and tried shorting rca to get a flat input and still there.
Any help would be much appreciated.
I have two planet audio TT2250d amplifiers having similar problems. On the output I get a triangle wave from 1-1.5v P-P. Fan not turning so checked driver Board and MPSA42 gets hot and I replaced with MPSW42, didn't change so I replaced all 4, still no change. With all 4 MPSW42 removed the MPSA56 get hot now, wave is gone on output. New MPSW42 into amp get hot and wave is back.
Power and output Fets good, removed inductors to check for shorts, wasn't sure if it shorted but I wedged wire over so it wouldn't in future, no change. One of the amps had one output cap blown off the board, replaced all 4, and checked inductors.
Rail voltage is +/-69.5
+/- 15 volts is ok
On the driver board is an IC that has number sanded off not sure if that is bad or what values should be.
Power IC values appear good.
All test with RCA unhooked and tried shorting rca to get a flat input and still there.
Any help would be much appreciated.
On pin 1 there is 0 volts.
Went back through driver board with soldering iron making sure traces/parts were soldered. Now triangle wave is gone on output but now on the speaker out I am getting almost square wave of 168Vp-p 112kHz(like the drv is being amplified), swapped driver board and same thing, now I might have two bad driver boards or something else in amp. Were else can I look or replace items.
Sorry about the down time from last post, Midwest blizzard of 2011 had me busy. I really appreciate the help.
Went back through driver board with soldering iron making sure traces/parts were soldered. Now triangle wave is gone on output but now on the speaker out I am getting almost square wave of 168Vp-p 112kHz(like the drv is being amplified), swapped driver board and same thing, now I might have two bad driver boards or something else in amp. Were else can I look or replace items.
Sorry about the down time from last post, Midwest blizzard of 2011 had me busy. I really appreciate the help.
Ok I removed driver board to check circuit traces, everything seems ok. With board removed, I hooked up sine wave to RCA and am trying to trace signal through amp. The IN+ of driverboard has no signal. I traced it through first 2 or three op amps and loose it, I am going to continue to trace it but was curious if you knew the path I am to trace through op amps? It seems something is up with 13600D IC or before this ic. Master/Slave has no effect.
13600D is getting -14.9v Bias input A and B and proper +/-15volt supply, but
pin 2 is 800mv
pin 3 is 200mv
pin 4 is 200mv
pin 5,7 is 0v
pin 8 is 8.66v
13600D is getting -14.9v Bias input A and B and proper +/-15volt supply, but
pin 2 is 800mv
pin 3 is 200mv
pin 4 is 200mv
pin 5,7 is 0v
pin 8 is 8.66v
If you can follow a schematic diagram, email me. I have one from a similar amp that should be helpful.
babin_perry@yahoo.com
babin_perry@yahoo.com
Ok traced signal. I removed IC107 and the output is noisey like below in attachment. IC107 replaced no signal, so I can say IC107 isn't bad but I am not sure yet what is causing this to happen? VR104A seems good, caps, resistors measure ok. I am still working through this, but curious if you have any ideas in this area of the amp to look for?
Attachments
I had the same problem in a Soundstream TRX2000d. (do you remember Perry?)
I thought that triangle was audible (impossible @60KHz, but i hear a costant whistle/HF noise with speaker connected).
I solved replacing the op-amp in driver board (original JRC4560) with an hi-speed op-amp LM4562.
I try NE5532 with some improvment..but still had a little HF audible noise.
In my case, LM4562 was good.
Triangle was reduced (a bit) but no audible noise at output.
Now amplifier works very well as original. Rock solid!
I thought that triangle was audible (impossible @60KHz, but i hear a costant whistle/HF noise with speaker connected).
I solved replacing the op-amp in driver board (original JRC4560) with an hi-speed op-amp LM4562.
I try NE5532 with some improvment..but still had a little HF audible noise.
In my case, LM4562 was good.
Triangle was reduced (a bit) but no audible noise at output.
Now amplifier works very well as original. Rock solid!
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