Echoplex won't erase.

[drewl]

I hate these things.

Anyway, early solid state EP2, electronics all correct, heads measure right, getting weak echo and it won't erase.

I think the heads are magnetized.

Anything else to check before I give up on it?

[Chuck H]

I use to have a degaussing pen. I don't know it there's a DIY way to do it without a unit made just for tape heads, I've never tried. Worst case you can replace the record/erase head for about a hundred bucks. I didn't bother with a link because I found parts so easily.

*NOTE: They sure know what to charge, don't they? That head price plus whatever else it may need is right on the edge of fixing it or leaving it in the closet on the "some day" shelf

[drewl]

Yeah, its not mine and I don't think owner wants to dump money into it.
I fixed his Line 6 DL4 which does Echoplex and more.

I've repaired several in the past but don't have the time to mess with it.

Thanks.

[Enzo]

Accumulated magnetic charge usually lops off the highs, not killing erase. In fact the erase head should demag itself constantly.

Get out your scope, is the pretty hot erase signal on the erase head? The same signal is used as record bias on the record head, is it there? It doesn't erase, but does it record? Oh yes, you say it records weakly. SOunds to me like your bias oscillator is not running.

[Leo_Gnardo]

SOunds to me like your bias oscillator is not running.

That right there. ^ ^ ^ Bet your heads are OK. Wouldn't hurt to demag, but if your bias circuit is weak, you'll have the symptoms you mentioned.

[drewl]

Dammit.

Had bias oscillator, oscillating like a mo-fo-
Wasn't getting where it needed to- small hairline crack on PC board.

Thanks again.

[Leo_Gnardo]

Had bias oscillator, oscillating like a mo-fo-
Wasn't getting where it needed to- small hairline crack on PC board.

Luv them hairline cracks, when you finde 'em & fix 'em you come up lookin' a hero! Yaaay!

[drewl]

Thumbs up thanks for giving me the idea to check bias circuit.

You forget things when you don't work on odd stuff after a while.
At least I do.

[uboat229]

my ep2 doesnt erase... not supposed to.... it rerecords over the old sound......sos might be dif

frank uboat

[Enzo]

Hi uboat, welcome to the forum.

That is not correct, it has to erase to make way for the new signal to be recorded. That is what the erase head is there for. Erasing is part of the recording process. See schematic below. if it had no erase function, it would lay new material down over the old, but the old would remain, causing an ever increasing pile of noise.

http://bmamps.com/Schematics/Effects..._5939-9067.pdf

[uboat229]

hi enzo.... i looked at your schematic and it shows three heads... mine has two actual heads and when i checked again i noticed the sliding head is actually a record and erase head.... i stand corrected....all this time i thought the recording function erased the old recording.....thanks... im not to old or dumb to learn something new afterall, or to admit i was wrong

frankie uboat