the right channel is great but left channel is crackling. the gain doesnt change the volume at all. when i turn the volume up on my radio i use for testing, the left channel cracks very loud and annoying. its ok when i turn the radio back down. the radio is the one i use to test amps and it works fine with other amps. its just the left channel of this old autotek. i moved the rca cables around and it isnt the cables.what could cause this? im kinda new to amp repair and im trying to get more knowledge.
If the gain pot makes no difference on the noisy channel but works properly for the other channel, the pot is likely defective.
It's also possible that you have an open shield. The RCA shield should read ~0 ohms to the non-bridging speaker terminals.
It's also possible that you have an open shield. The RCA shield should read ~0 ohms to the non-bridging speaker terminals.
autotek xi? known for bad pots, fairly simple to fix. part # should be on the pot. parts express probally has it in stock.
the pot was bad
i cleaned the pot with contact cleaner and moved it back and forth. i noticed it had a little catch in it and wasnt smooth.it was also at an angle. i tried to straighten it up and part of it broke off with the soldered legs on it. i then turned it and it moved very smoothly. what i gathered was that it was in a bind and was causing it to not conduct like its supposed to. i need a new pot. its the gain pot and has "820kx2" stamped on it and below that a J with a symbol and AU next to the J and symbol . i guess i can find one of these in the mouser electronics catalog and ill try to find out if i can find one.
i cleaned the pot with contact cleaner and moved it back and forth. i noticed it had a little catch in it and wasnt smooth.it was also at an angle. i tried to straighten it up and part of it broke off with the soldered legs on it. i then turned it and it moved very smoothly. what i gathered was that it was in a bind and was causing it to not conduct like its supposed to. i need a new pot. its the gain pot and has "820kx2" stamped on it and below that a J with a symbol and AU next to the J and symbol . i guess i can find one of these in the mouser electronics catalog and ill try to find out if i can find one.
To prevent damaging the board, apply enough new solder to the 3 legs of each section of the pot so that you can lay the tip of the soldering iron across them and heat all 3 at once. Heat all 3 and when the solder is hot enough, the pot should pull free with very little force. Don't try to remove it until the solder is molten on all 3 legs. The vias in the board are easily pulled and if damaged, can make it difficult to get a new pot to work as it should.
cant find replacement part
i looked on the digi key website and i couldnt figure out which pot is which. the one i took out of the amp says B20k x2 . which tells me its a 2 way 20k pot. im not too familiar with the terminology on the pot specs on the digi key website. which pot should i replace it with? im not gonna try radio shack. we have a local electronics store but i dont know what to tell them when i call for the part.
i looked on the digi key website and i couldnt figure out which pot is which. the one i took out of the amp says B20k x2 . which tells me its a 2 way 20k pot. im not too familiar with the terminology on the pot specs on the digi key website. which pot should i replace it with? im not gonna try radio shack. we have a local electronics store but i dont know what to tell them when i call for the part.
There are so many variables that you're unlikely to find a drop-in replacement unless you salvage one from another autotek (or similar) amp or preamp. If you can't find a replacement, you could move one of the other pots to the gain position. You may have to replace the missing pot with resistors (I'm not sure how they're being used in this amp). You could also replace the gain pot with resistors if you want to retain the bass/treble function.
Autotek has them and they want $18.00 each for them + shipping. Call Autotek. They use to be located in Burlingame CA. Near the Air port . (San Francisco air port). Been there a few times in my past life and I might even have one or two myself left over from old stock. Does yours say B20K on it ?
Not cheap but its a drop in replacement from them....🙂
I think they moved back east somewhere. Its been 5 years since i bought the last 4 pots I got off them, but I'm getting a nag that they are back east now.. Sorry for the mis-direction of their parts support ops...
Not cheap but its a drop in replacement from them....🙂
I think they moved back east somewhere. Its been 5 years since i bought the last 4 pots I got off them, but I'm getting a nag that they are back east now.. Sorry for the mis-direction of their parts support ops...
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yes pot says b20k on it
yes thats the one i need. theres got to be another vendor that sells them for a couple dollars.
yes thats the one i need. theres got to be another vendor that sells them for a couple dollars.
its physically damaged. it was bent and i tried to bend it back and broke it. I believe it was bound up and not adjusting the gain in the first place.
If/when you remove it, apply additional solder to all legs of the pot. Lay the tip of your iron across 3 legs at once. When the solder is molten on all 3 legs, pull that half of the pot out. This only works if one of the circuit boards on the pot is broken (which yours is). It will keep you from pulling the vias out of the board.
You can use a non conductive electrical wash spray to clean that pot and it should work like new.
In the pic to the left you will see the exact used old style pot Autotek once used in their amps < Actually ZED >. To my knowledge Autotek never had any engineers or build shop areas, just a warehouse located near the SF airport as a sales office and shipping facility. But never any engineering headquarters and or build shop. ZED built most of their older gear like the amp you have. Autotek and Hifonics were just sales names with NO engineering or internal technical back bone, Just a sales group and a name.. nothing more...Sorta like they are today...
ZED audio might have replacement pots < big maybe but they also used these same pots on most of all the older Hifonics amps also. just not the same value.>
On the right you will see three brand new replacement pots sold to me by Autotek four years ago for $18.00 each + shipping. I actually bought 5 and used two in a guys amp so it would all be like new....Hence my spare exact USED pot left over.
I wish you luck on finding cheap replacements, the rear body size is the issue and the notch located up front to align the pot to the case and lock it in so it does not twist with knob spin. Other then that the value of 20K ohm dual gang pot is the generic info required.
Are mine for sale ? Sorry, no I have scruples and I kept these so I could maintain fast turn around even if it cost me out the back end like these did.....😱
ZED audio might have replacement pots < big maybe but they also used these same pots on most of all the older Hifonics amps also. just not the same value.>
On the right you will see three brand new replacement pots sold to me by Autotek four years ago for $18.00 each + shipping. I actually bought 5 and used two in a guys amp so it would all be like new....Hence my spare exact USED pot left over.
I wish you luck on finding cheap replacements, the rear body size is the issue and the notch located up front to align the pot to the case and lock it in so it does not twist with knob spin. Other then that the value of 20K ohm dual gang pot is the generic info required.
Are mine for sale ? Sorry, no I have scruples and I kept these so I could maintain fast turn around even if it cost me out the back end like these did.....😱
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