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Miscellaneous Automotive
Car Performance & Repair
Autotek 99 - Strange repair by previous owner
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<blockquote data-quote="Wachu" data-source="post: 8560228" data-attributes="member: 672795"><p>Hi guys. At first i must admit that English is not my native language. I know its not at good level, but i hope you can understand what i mean.</p><p></p><p>I recently bought an Autotek 99 car amplifier, made by Zed Audio 1994.</p><p></p><p>(The PCB board tell us its Revision C which i cant find on google image)</p><p></p><p>It cost me 25$. I saw that couple of them was sold on this forum for 100$+, so i thought it was a good price. Seller told me that he is not first owner and he dont know if the amp was repaired, but its fully working. I bought it without asking for photos of inside, just to not waste time (someone else may take it in any moment)</p><p></p><p>I connected an amp when it arrives. both of two channels works identically, there is no crappy sound or distortions (i only tried to playin at 2/10 of volume, but i hope thats enought to say its working correctly)</p><p></p><p>When i opened it i did sad face, because it was repaired by someone.</p><p></p><p>i removed the IMG tags because photos are too big</p><p></p><p><a href="http://i.imgur.com/nNvoD2Y.jpg" target="_blank">http://i.imgur.com/nNvoD2Y.jpg</a></p><p></p><p>1. Somebody added a capacitor (Nichicon 3300uF 35v). It's probably connected between B+ (12v) input signal and this small black diode.</p><p></p><p>2. The coil is also smeared with silicon (maybe to reduce the noise of coil?)</p><p></p><p>3. Im not 100% sure, but also some of the left side transistors looks like they was resoldered (i cant look closer, cause i dont know how to remove those black clips between the transistors and metal. They are very strong and i won't to break anything.)</p><p></p><p>Questions:</p><p></p><p>Can you explain what somebody wanted to achieve by adding this one more capacitor?</p><p></p><p>Transistors looks like resoldered.. Is there chance that somebody inserted a fake's transistors? If yes, does it means that amp is worthless?</p><p></p><p>I have a chance to replace this Autotek for used Boston Acoustics GTA802, fully working in a good condition. Shall i do it? Im looking for strong mono/2channel amp for my rockford fosgate sub. Which of those two will be better?</p><p></p><p>Also, shouldnt the input level potentiometer act like regular volume control?</p><p></p><p>I mean if i connect this amp in home (i dont have my car audio completed yet), to the PC using 2x cinch &gt; jack cable, even if the input level on amp is at minimum and the windows control is at 20/100 it sounds loud. If i set a input level higher volume get increased by little, so the potentiometer by self is working.</p><p></p><p>If you need additional informations or photos, just tell me. I would really appreciate your help. I'm starting my journey with Car Audio.</p><p></p><p>More photos:</p><p></p><p><a href="http://i.imgur.com/KtJdAVV.jpg" target="_blank">http://i.imgur.com/KtJdAVV.jpg</a></p><p></p><p><a href="http://i.imgur.com/6FYuZF1.jpg" target="_blank">http://i.imgur.com/6FYuZF1.jpg</a></p><p></p><p><a href="http://i.imgur.com/LpNTI1T.jpg" target="_blank">http://i.imgur.com/LpNTI1T.jpg</a></p></blockquote><p></p>
[QUOTE="Wachu, post: 8560228, member: 672795"] Hi guys. At first i must admit that English is not my native language. I know its not at good level, but i hope you can understand what i mean. I recently bought an Autotek 99 car amplifier, made by Zed Audio 1994. (The PCB board tell us its Revision C which i cant find on google image) It cost me 25$. I saw that couple of them was sold on this forum for 100$+, so i thought it was a good price. Seller told me that he is not first owner and he dont know if the amp was repaired, but its fully working. I bought it without asking for photos of inside, just to not waste time (someone else may take it in any moment) I connected an amp when it arrives. both of two channels works identically, there is no crappy sound or distortions (i only tried to playin at 2/10 of volume, but i hope thats enought to say its working correctly) When i opened it i did sad face, because it was repaired by someone. i removed the IMG tags because photos are too big [URL="http://i.imgur.com/nNvoD2Y.jpg"]http://i.imgur.com/nNvoD2Y.jpg[/URL] 1. Somebody added a capacitor (Nichicon 3300uF 35v). It's probably connected between B+ (12v) input signal and this small black diode. 2. The coil is also smeared with silicon (maybe to reduce the noise of coil?) 3. Im not 100% sure, but also some of the left side transistors looks like they was resoldered (i cant look closer, cause i dont know how to remove those black clips between the transistors and metal. They are very strong and i won't to break anything.) Questions: Can you explain what somebody wanted to achieve by adding this one more capacitor? Transistors looks like resoldered.. Is there chance that somebody inserted a fake's transistors? If yes, does it means that amp is worthless? I have a chance to replace this Autotek for used Boston Acoustics GTA802, fully working in a good condition. Shall i do it? Im looking for strong mono/2channel amp for my rockford fosgate sub. Which of those two will be better? Also, shouldnt the input level potentiometer act like regular volume control? I mean if i connect this amp in home (i dont have my car audio completed yet), to the PC using 2x cinch > jack cable, even if the input level on amp is at minimum and the windows control is at 20/100 it sounds loud. If i set a input level higher volume get increased by little, so the potentiometer by self is working. If you need additional informations or photos, just tell me. I would really appreciate your help. I'm starting my journey with Car Audio. More photos: [URL="http://i.imgur.com/KtJdAVV.jpg"]http://i.imgur.com/KtJdAVV.jpg[/URL] [URL="http://i.imgur.com/6FYuZF1.jpg"]http://i.imgur.com/6FYuZF1.jpg[/URL] [URL="http://i.imgur.com/LpNTI1T.jpg"]http://i.imgur.com/LpNTI1T.jpg[/URL] [/QUOTE]
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