I checked (and rechecked) several times to verify the drivers were in the correct location. Do you have any confidence in the driver transistors/outputs that mcm sells? I was trying to get everything ordered in one shot but if mcm is not good for fets I will go elsewhere. Mouser has some equivalent's for the drivers but I was nervous about using them after having trouble with the nte parts.
The substitutes that you have shouldn't cause you to have any DC on the outputs. What were the two NTE parts and what were the original drivers?
Yes but when I originally installed those replacement drivers I still had the 688's and 718's in the amp. I have yet to try the replacement drivers with the new outputs installed. Do you think it is worth a shot?
I guess it is a possibility although they still measure ok. I have an untouched pair of those same nte drivers. I will install those along with the new outputs and see what happens.
Well I installed the new pair of drivers and fired the amp up and it powers on normally through a 5 amp fuse. No excessive current draw and there is no longer 35 volts dc present on the speaker output. It's late so I can't get it going too loud at all but from what I can hear I now have clean sound on both channels as well as bridged. So awesome news there. I still had the original pair of NTE drivers laying around and I didn't believe them to be bad so I decided I would try these in the amp one last time(I just had to know if these were the problem). Well with this pair installed the amp still powers on and functions normally so apparently one of the original outputs I was using for troubleshooting was a little too far gone and causing my problems. I can't run the amp full bore as I only have two of 6 power supply fets installed currently but I am hoping that I have the demons worked out of the audio section. We shall see once my ps fets show up.
🙂 congrats! get some quality parts in there asap and let us know how she ends up!
Got to <3 community help.
Got to <3 community help.
Unfortunately there is no good local source for PS fets. Only place in town that might carry stuff like that wants over 5 bucks a piece for nte equivalents of IRFZ44N. Needing 6 there is no way I am paying that much. Got some FQP50N06's on the way from digikey for about 1.20 a piece. They are closer to what the original PS fets were anyhow and at 1.20 a piece the price is much easier to swallow even after shipping plus I needed a couple of caps for another project anyway. This amp wasn't really worth all this trouble as it is a very cheap knockoff of a kenwood amp but I took it as a challenge to myself to repair it because the board was burnt so badly in the power supply. It looks as if somebody tried to solder in what they thought were ps fets to replace some other blown parts and it caused a catastrophic melt down. A couple of the through holes were burnt completely out of the board.
New PS fets showed up yesterday and I got them installed today. Amp appears to be working normally. Ran it at full output for 20 minutes plus with no issues. In case anybody was wondering this mystery amp is a Phonics Digital PD-2613 . Probably the worst burn I've had to deal with but she appears to be running flawlessly now.
SWEET!
I know what you mean dude. I just fixed an LA Sound Sunset 100. What a chinese wreck... Its funny though cause it uses darlingtons for outputs. Ive got nothing left under my workbench to fix today.
I know what you mean dude. I just fixed an LA Sound Sunset 100. What a chinese wreck... Its funny though cause it uses darlingtons for outputs. Ive got nothing left under my workbench to fix today.
Yeah as of right now I have nothing that needs repair. Kinda bugs me not having anything to work on but people want so much for their blown amps it seems. It's like "oh its blown so i'll knock like 20 bucks off". I'm not trying to make money but I'm not looking to get taken to the cleaners either.
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