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Post by svart on Mar 11, 2016 12:54:08 GMT -6
So I bought a beat up EP3 on ebay. No wood box, but the rest of the unit is there. It looks like it's going to need some love. I'll post pics of my progress on here..
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Post by noah shain on Mar 12, 2016 12:22:12 GMT -6
So I bought a beat up EP3 on ebay. No wood box, but the rest of the unit is there. It looks like it's going to need some love. I'll post pics of my progress on here.. I have a working, but noisy one. Interested in your progress here! Maybe I'll parallel you  |
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Post by rowmat on Mar 12, 2016 15:32:03 GMT -6
Another one here too!
Add me to the list!
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Post by noah shain on Mar 15, 2016 18:25:19 GMT -6
Oops. Mine is a 2. Tubes. 3 is solid state right?
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Post by rowmat on Mar 16, 2016 0:46:19 GMT -6
Mine is a solid state EP3 I believe.
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Post by svart on Mar 16, 2016 8:05:39 GMT -6
Oops. Mine is a 2. Tubes. 3 is solid state right? Yeah, the EP3 is solid state. It's the circuit basis for the EP booster pedal too. So I messed around with the unit some.. I installed a new 3 wire power cable since the old one was cut off. I recapped all the electrolytic caps. I replaced one of the pots that was really crunchy while turning it. So far I have very little noise playing guitar straight through it, and I hear the old guitar that was on the tape, but I have only a really faint guitar being recorded to the tape. I'll need to probe around a bit to see if it's the head, the wires to the head or the circuit driving the record head which is causing my lack of level. |
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Post by svart on Apr 8, 2016 15:05:27 GMT -6
I've started to get around to working on this again. I pulled a couple of the pots out, and then got too busy to bother ordering them.. I just ordered them and should get them soon.
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Post by svart on Jul 6, 2016 7:22:05 GMT -6
I actually had time to work on this over the long holiday weekend.
I replaced all the pots, which only fixed the scratchy pot issues, but did not fix the record level issue.
I made a guess and figured that the erase head was bad, or not working. Ohming out the record head showed near-proper resistance, so I then moved to the HV generator. There was no output and only one of the driving transistors was hot, so I started troubleshooting. I ohmed out all the resistors, which were *close* to their supposed values. At least they were close enough to work as intended.
I then ohmed out the transformer, which was good, but when I moved backwards to the transistors, I noticed that one was not ohming out correctly, showing open circuit to the transformer.. A close visual investigation found a hairline crack in the solder at the eyelet to the transformer pin..
A quick dab of fresh solder, and the HV was working again.
I plugged the unit in, and gave it a go, and it works great!
So now I need to build a box for the unit and I'll have an EP3 to use in the studio.
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Post by svart on Jul 6, 2016 9:25:25 GMT -6
Next thing I might do is fashion a selection switch that allows me to only use the preamp portion of the unit, and turn off everything else in the unit.
That way I can use the front end as a booster, just like the "EP booster" pedals (which are clones of the preamp of this unit) while saving the tape, motor and heads.
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