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New AWH-023 boards from afinity for artifacts off eBay for SA-9100

C

Clay1955-7

Member
wondering if anyone has used these redesigned amp boards, I put them in my 9100 because the old right side board had issues with solder pads lifting, the new board and all new components look great, but I keep getting a short and I can’t find what is wrong, I checked and double, tripled check the components as I was building the boards and have had them in and out several times trying to find anything wrong
 
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Pix may help. Assume dbt is bright on power up, is it bright or somewhat bright.
Mica insulators? (don't know the amp)
 
Yeah starts getting bright at about 50 watts, if I pull the wire in pin #14 ( the +45v for both sides ) the left side and leave the right side in its shorted and if I pull 14 wire from the right side and leave the left in its shorted if I pull both #14 wires the short goes away mica is good no grounding on the outputs. Picture is new board and old board
 

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Here are schematics for old foil and the other was sent from affinity for artifacts about new board but can’t believe it is the boards because of what I wrote in the last post about pulling #14 wire
 

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Here is the back side of new board as you can see it has DNP pin #2 & 10, - I’m pretty sure it’s a short, I was hoping someone that may have rebuilt a 9100 with these boards may know - I followed the ground for #7 pin on right side and it doesn’t hook to anything on the left it grounds at the preamp stage so since both side interact with each other I guess it uses the left side or does it I don’t know
 

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So what you mean when you say the bulb gets bright at about 50 watts? If your device is pushing 50w, the bulb is going to bright without any sorts.
 
I meant preamp switch not stage, I put the right side in first and DBT failed and I thought it may be because the left side needed to be in but it still failed the DBT after installing it
 
So I figured. Have you tried starting without Variac, on the DBT only, with all boards plugged in? DBT gets bright, and then dims if everything is working ok... unless bias is set too high.
 
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Yep I think I’ve tried about everything the bias is turned all the way down bulb stay bright W/O the variac, Ive had the heat sink in and out so many times I can do it blind folded new board has screw terminals I like that makes it easy to remove - I’m thinking about working on the old boards and put them back in just to see what happens
 
Clay1955-7 said:
Here is the back side of new board as you can see it has DNP pin #2 & 10, - I’m pretty sure it’s a short
Click to expand...
Not sure exactly what you mean, can you measure the resistance between pins 2&10 , amp powered off, it should be k-ohms(at least)
 
Yeah I’m not good at explaining; I’m getting 0.2ohms between with continuity - left side has continuity between #7 and the chassie right side does not - so much of the left side board jumps to the right but #7 don’t I haven’t try to jump that wire
 
It seems the right side board is not grounded and A.I. is telling me not to jump from the other board - the ground wire for the right side is in a harness with #4 & 5 wire but it does not come out of that harness at the preamp switch like the other side does
 
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