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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.



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?

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?


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:



 

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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.



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?

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?


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:



Sorry no one responded t your post. I'm not a tech, but it looks to me as if the board had caught on fire and melted the contacts beneath the added capacitor. Whoever "Jerry-Rigged" this repair essentially covered the board in solder and used the capacitor itself to make a connection.

As far as the silicon on the transformer, that's normal. I wouldn't worry about that.

I wouldn't use this amplifier. It's not safe as amps get very hot when playing loud and this repair is temporary at best. It will likely catch on fire again. Just my opinion. If you trade it someone else may have it catch on fire in their car.

Again, this is just my opinion. There are experienced techs on this board that know A LOT more than I do as I'm just a hobbyist. However no one responded, so...

Sent from my Nexus 5X using Tapatalk
 

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And the cap in slot C13 is bulging. It should look like the cap in C12 with the yellow around the ring on top. See how it is rising out of the foil? Good luck on fixing it. Maybe you can find someone to do the work for you.
 

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I do not know that amp, but here's some speculation:

There was a vertical 3300 uF where the horizontal one he added is now. It may have badly leaked, scorching the board and the related traces. So, to get it to work, he added the horizontal one over the scorching, bypassing the damaged traces to make the necessary connections.

If the board is scorched on an amp, there are many repair guys that won't touch it. Even if they do get it running, it will never be quite the same, and since it looks off people assume they did something wrong.
 
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