hey guys i am new to this site so please disregard any noob actions from me... alright I have a clif designs cd860hc amplifier.
The problem: When i have it hooked up and turned on it goes into protection mode right away. while in protection mode the amplifier pusles. you can see it dim the lights. there is a huge amount of current being drawn. measured aprox. 180-210 amps during the pulse... it does it with rca's disconnected and speakers disconnected. also when the speakers are hooked up the pulse goes through them. I have visually inspected the board and don't see anything.. I have limited electronics experience. mostly diagnosis of wiring faults in vehicles but willing to learn new things. Any help is well apprieciated. thanks
The problem: When i have it hooked up and turned on it goes into protection mode right away. while in protection mode the amplifier pusles. you can see it dim the lights. there is a huge amount of current being drawn. measured aprox. 180-210 amps during the pulse... it does it with rca's disconnected and speakers disconnected. also when the speakers are hooked up the pulse goes through them. I have visually inspected the board and don't see anything.. I have limited electronics experience. mostly diagnosis of wiring faults in vehicles but willing to learn new things. Any help is well apprieciated. thanks
This is most likely due to shorted output transistors.
If you can post photos of the inside of the amp, it would be easier to guide you through the troubleshooting. If you can provide high resolution photos, email them to me. It will make it easier to see the numbers on the board.
babin_perry@yahoo.com
If you're new to amp repair, read through the basic repair page below.
If you can post photos of the inside of the amp, it would be easier to guide you through the troubleshooting. If you can provide high resolution photos, email them to me. It will make it easier to see the numbers on the board.
babin_perry@yahoo.com
If you're new to amp repair, read through the basic repair page below.
Check the A1695 and C4468 transistors to see if any are shorted. With your multimeter set to ohms, if you find anything near 0 ohms between the legs of any individual transistor, the transistor is likely shorted. Check with the meter leads across the legs 1-2, 2-3 and 1-3. They generally short 2-3.
hmmm. The only pictures i can get are from a crappy cell phone. I will email them to you to see if they even help any. thanks for the help...
The information you provided was good enough at this point. Measure the resistance and let us know what you find.
Do this with no power applied to the amp.
Do this with no power applied to the amp.
I believe I have found three A1695 transistors shorted.. The three are in a row and the first 2 legs are shorted. showed about 6 ohms and the rest were about 300 ohms. Any thing else i should consider to be faulty too?
The driver transistor (medium sized transistor standing near the emitter resistors) driving them or the driver transistor driving the other output transistors in that channel could be defective.
Pull those 3 transistors and check them out of the circuit. It's likely that only one is actually shorted. Reinstall the other two (if they're OK), clamp the transistors to the sink and see if it will power up.
You'll have to replace all 6 of the transistors 2SA1695 transistors in that channel. Check the large emitter resistors connected to the 6 transistors to make sure that all are within tolerance.
Pull those 3 transistors and check them out of the circuit. It's likely that only one is actually shorted. Reinstall the other two (if they're OK), clamp the transistors to the sink and see if it will power up.
You'll have to replace all 6 of the transistors 2SA1695 transistors in that channel. Check the large emitter resistors connected to the 6 transistors to make sure that all are within tolerance.
I am stumped... I pulled the three transistors and diode checked them and they seem fine.. I put the pos on leg 3 and the neg on 1 then 2 and both read about .5 which is fine to me. on the other combos it read OL. To my knowledge this means it is fine.. Am I wrong?
I left all three out and hooked it up.... you can hear it pulse but doesn't pull the extreme amperage now... when you listen to it you here it running then it goes tick and the fan slows down like power is being pulled down. then is goes back to normal then tick. P.S.. I forgot to mention it made this ticking sound before too. When it ticked you could see all the lights dim and my subs would pulse with it to. Now it ticks but doesn't go through the subs and it does pull as much amperage now.
On diode check, 0.5v from 2-3 means the transistor is defective.
Check the driver transistors to see if any appear shorted.
Check the driver transistors to see if any appear shorted.
Which ones are the driver transistors? I just want to make sure I am testing the correct component. Thanks for all the help
The medium sized transistors standing near the large white emitter resistors. Check all 4 in the channel where you removed the output transistors.
alright I checked them and the two on the far left had reading of about 1.6 ohms on one of the combos. the other two seemed to test alright.
Did you pull them and test them or did you test them in the circuit?
Since you said they 'seemed' to test alright...
You need to pull all 4 drivers to check them. If you're unsure of the readings, use the form on the following page.
http://www.bcae1.com/repairbasicsforbcae1/repairbasics.htm
Send me the screen caps or post the images here.
If you can't find the form, look for the word 'this' (yellow text). Scroll down to the part of the page that shows you how to check bipolar transistors. The attached image is the area you're looking for.
Since you said they 'seemed' to test alright...
You need to pull all 4 drivers to check them. If you're unsure of the readings, use the form on the following page.
http://www.bcae1.com/repairbasicsforbcae1/repairbasics.htm
Send me the screen caps or post the images here.
If you can't find the form, look for the word 'this' (yellow text). Scroll down to the part of the page that shows you how to check bipolar transistors. The attached image is the area you're looking for.
Attachments
alright i pulled them and sent the screen caps to you.. only one obviously appeared faulty to me..
o crap.. i forgot to change the part number.. the B631 3 and B631 4 pics i sent you are actually D600K's
No, but I'd replace the two with the same part number (2SB631K).
The K version of the 2SB631 is difficult to find. If the large rail capacitors are rated for more than 50v, the rail voltage may be too high for the non-K version. Are the rail caps rated for more than 50v?
If so, the following part from Mouser may be a good sub. I've never used it but the specs look right.
512-KSA1220AYS
The K version of the 2SB631 is difficult to find. If the large rail capacitors are rated for more than 50v, the rail voltage may be too high for the non-K version. Are the rail caps rated for more than 50v?
If so, the following part from Mouser may be a good sub. I've never used it but the specs look right.
512-KSA1220AYS
I checked the emitter resitors and got a reading of .3 to .4 ohms. So they seem good... i thought you would want a lower value for the emitter resistors. like .1 ohms?
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