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Help with 8080DB

III in your picture goes on the back of the tuner unit, to the right, rear of the chassis ( looking at the unit from the front). Good thing is, it should only fit on its mating connector, it would be tough to jam it on to another connector.
 
Tinman said:
Actually, re-locating the resistors is the mod. It involves using ONE 10watt resistor (not sure of the value right now) and attaching it to the metal frame behind the board. I did this to my 9090db, and it runs much cooler.

Change out those caps!!

I'd have to pop the cover on my 9090db if anyone wants a pic and the resistor value.
Click to expand...

I'd like a picture and the value of your resistor if it's not too much trouble.
 
Here are a few pics of my modification. I searched thru several threads on the forum to find out what everyone else was doing. I used a 200 ohm, 20 watt resistor. I mounted mine just off to the side of the board, but I think most mount theirs on the back wall of the tuner chassis. I elected not to do that because of the proximity to the wiring that passes thru the chassis back there. My new resistor is still fairly close to the original baord but it will still drop the temperature considerably. Another thing I did (paranoia) is I ran two conductors to each side. This splits the current up (and heat) so that the wires should run cooler too. I had some fiberglass insulated wire at work and used it. Technically a 10 watt resistor should be fine and might be a little smaller and might fit better on the rear of the chassis. The pics should give you an idea anyway.
 

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I decided that as long as I have the power board out I may as well make the modification. I read all the threads I could find on the mod. and will see if I can mount a single 200 ohm 10 or 20 watt resistor to the rear chassis with a heat sink on the other side. Barring that I'll mount the resistor against the side. Parts Express carries a 10 ohm 150 and 220W but no 200W. 150W would work but I'd rather the 200W for superior heat reduction. Where can I get them? Thanks for the pics.
 
I bought mine from http://www.Mouser.com

The 200 Ohm, 20 watt resistor is part number 71-HLW20-A1Z-200 ($2.46 each)
The mounting bracket is 71-BRACKET203E29 ($0.48 each). I believe you will need 2, one for each end

They may have a minimum order, another thing you could buy would be some heat transfer paste, to put on the back of TR-01 where it mounts to the heat sink and possibly on the resistor brackets where they meet the chassis and on the back of any other heat sink you use.
 
If you can't find a 200 ohm resistor in stock, a 220ohm (more common) works just as well.

BTW, the heatsink now just gets warm. No longer an issue for the capacitor next to it. The original problem was that they were dropping too great a voltage to get 12.5 volts.
This had to be burned off as heat. The larger resistor does a better job of this than the regulator transistor.

NO, the metal does NOT get hot enough to harm the wires.....:rolleyes:
 

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Tinman I like your 200 ohm resistor arrangement. Did the mounting bracket come with it or did you make it?
 
That's a 220ohm resistor I liberated from a power supply, bracket and all.

Been playing the 9090db all day today, heatsink is hot but normal hot. The metal next to the wires is only warm. The resistor is too hot to keep a finger on it, though. It's doing it's job.

Great jazz on tonight.
 
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