Echoplex EP3 Please help

[jun]

Hello all,

I am trying repair of the echoplex EP3 which get at ebay.

I can not get any echo effect…



When power is ON, the pilot lamp turns on. Moter is working and tape is running correct position.
Also when I play guitar, I can get sound without echo from amplifier.
Tape cartridge is new which get from ORBIT ELECTRONIX.

In my EP3, Sound on Sound head is missing. However I suppose Echo should be effected without SOS head.

I am very glad that if I can get advice for solutions.

Thanks
JUN

[rgorke]

A couple of things, first, do you have a footswitch with a cable 1/4 inch cable. Switch it on and off to make sure that there is not a hang up there.

Also, the Echo and SOS switch might be backward and switch that back and forth.

THen, make sure your record pot (located below the board and accessed through hole in panel), make sure that is turned up to record the signal on the tape.

Report back and we can help with the next steps. There are some other things like the trim pots that deal with the bias for the recording on the tape.

Good Luck

[jun]

rgorke, Thank you for careful advice.

I checked the items which you pointed out as follows:

1) I have not footswitch for EP3. I used my Fender twin reverb foot switch with 1/4 inch conversion plug. When I plug in ECHO/OFF jack and Switch it on and off, pilot lamp is ON with both switch on and off. There was no change in the sound.

2) Yes, The Echo/SOS switch is backward as Echo position.

3) As initial setting, the record pot was setting at 12 o'clock. Then I turned it to the clockwise more, but there was not the change.

I have to inform you, when I got this ep3, the wiring of the record/erase head is unsoldered on PCB.
Then I soldered in reference to some gutshots on the internet.　I attached an image of my wiring.



Thanks
JUN

[jun]

rgorke, Would you please let me know next step for solution ?

JUN

[guitar007]

Have you cleaned and demagnetized the heads? Have looked over the circuits carefully looking for anomalies...burned out, missing, loose components? I had an EP 2 that had a broken input resistor that was not perceptible until I began tapping components with a chopstick.

[Tazin]

Make sure the heads are clean.
Check for any loose or unconnected wires.
Check wiring at ECHO/SOS switch. You can even try bypassing the switch completely by running a jumper from the playback head wire at the switch to the connector on the first board.
If it's a playback head misalignment, try gently moving the playback head bracket up and down with your fingers to see if you can hear an echo....Be careful not to permanently reposition the head through.
Check the voltages and head resistance(s) against schematic.

[jun]

Thanks for advisees. I will check at tomorrow carefully.

Thanks
JUN

[rgorke]

Yeah what they said!! Also, that trim pot to the right of your picture is the key to getting good echo as it biases the recording to the tape. One is "suppose" to use a scope to adjust the pot with a test frequency. Since I don't have a scope, I uses a plastic screw driver, or something that will fit in that slot, and did some minor adjusting while the unit is running with a guitar plugged in and plugged into an amp. Mark or notice where you start. This isn't like adjust a truss were 1/4 turn gets you where you want to be it is more like going from 12:00 to 12:01 on a clock. Very little change can get you what you need. I always just hit one note to see if it is working the way I turned. If not try the other direction.

Also, I will try and find a picture of how your record/erase head is wired and make sure that is right.

Last resort idea is maybe your record head is bad. But we will try these other things first.