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RE: Cracks in EDP (question for Kim)



Dave-

you definitely put it in backwards. the blank side should be facing the
back of the unit. I noticed that those parts have changed a bit over the
years so they don't fit in as neatly as they used to in that spot. You have
to bend the leads so it leans back a little bit.

kim


At 10:04 PM -0800 1/23/01, future perfect wrote:
>I ordered the voltage regulator from DigiKey, and put it in, but I am
>getting some weird results. Either the display flickers a few times and
>turns off completely, or a few LEDs just stay on. This is on a short
>power-up after I put in the part- methinks I screwed up somewhere.
>
>I took #'s u40 & u28, as well as the heatsink out
>The new voltage regulator will only fit in one way, with the 'blank PC
>board' side facing the front of the unit.
>I am guessing "pin 3, on the right when looking at the front of the part" 
>is
>pin3 on the right with the blank side facing me. Let me know if it makes
>sense what I did, and please tell me where things went horribly wrong.
>
>thanks!
>Dave Eichenberger- guitars.loops.devices
>http://www.hazardfactor.com
>
>
>
>
>>
>> You need to change the two +5V linear regulators at the back of
>> the unit to
>> a switching regulator. These are 5 volt regulators U40, and U28. When 
>you
>> take the top off the echoplex, they will be the two in the back
>> attached to
>> the heatsink. These power two 5 volt digital sections.
>>
>> The part used in current Echoplex production to replace these is the 
>Power
>> Trends (http://www.powertrends.com/) PT5101N 5V switching regulator. You
>> should be able to get this part from Digikey (www.digikey.com). This 
>part
>> is a drop-in replacement for the standard 3-pin linear
>> regulators, and they
>> work great. You can actually use one of these to replace both of
>> the linear
>> regulators, and it works just fine. This is what they do in
>> production now.
>>
>> You need to take the PCB out of the chassis to do it. To do that, 
>unscrew
>> the front panel, unscrew the pcb, unscrew the heat sink from the back, 
>and
>> remove the nuts from the jacks on the back. It should pop right out. 
>What
>> you want to do is unscrew the regulators from the heatsink. Desolder and
>> remove both U28 and U40, the linear regs. Take the heat sink out
>> altogether
>> since it will be in the way, and you won't need it anymore.
>>
>> Solder the PT5101 into one of the regulator spots (the left one is a 
>good
>> choice). The PT5101 is pin compatible with the linear regs, so
>> there should
>> be no trouble with that. Now solder a wire from it's output pin (pin 3, 
>on
>> the right when looking at the front of the part) to the output hole 
>(pin 3
>> again) for the other regulator location. Use reasonably thick wire,
>> probably 18 gauge is ok. This way the PT5101 will be supplying power for
>> both the +5V rails the old regulators powered. Put the PCB back in the
>> chassis and screw it back together. Now power it up and make sure
>> it works!
>> You should see the Echoplex runs practically at room temperature now, 
>and
>> hopefully that cures the trouble.
>>
>> Let me know if you have questions.
>>
>> kim


______________________________________________________________________
Kim Flint                     | Looper's Delight
kflint@loopers-delight.com    | http://www.loopers-delight.com