Echo chamber repeating only ONCE!

[pretolocus]

Hi.
Like much others I bought a Echolix echo chamber EM- 110 (Univox, Melos...) and it arrived to me in a bad working order.
I think I have read all the threads that google brought to me, and I didn’f found an explanarion to my problems.
Let’s go explaining.
I can hear one echo. Once and only once. And very low, for listen to it I have to put practically the echo balance at 100%.
Both heads works well, and also the tape. Remember that I can hear one repetition (and I love how it sounds).
I soldered both heads in both positions and both recorded on the writing position, but I can’t hear nothing on no one of them when they are in the reading position, I don’t know if that say something, I read that they have to sound if you get it closer to a magnetic field (I did it).
Help please!
Thank you all.

[g1]

Not sure what you mean about getting it closer to magnetic field, there are special tools to DE-magnetize the heads.
The tapes also wear out, have you tried a new tape?

[pretolocus]

When you get closer a head to a movil phone, for example, the head makes some noise, at least the writing one. Perhaps I am not explaining me very well in english.
I changed the band of the tape, and I got the same one repetition.
There are too expensive in Europe, but I think the tape is in good shape. I changed the pads too and the wheel fits well.
Thank you!

[J M Fahey]

You get one repetition per playback head.

To get more, you must feed back some of the echo back into the input, so it gets repeated many times, each one weaker and duller of course.

Google the schematic, you might get lucky, but in any case post a couple pictures, at least one each from front panel, controls, and head assembly.

[pretolocus]

Ok! Here are the pictures. I could't find the schematic for my model, I found for the Em-80A and the Em-120, but there aren't exactly the same...
Anyway, you can see them too in the link.

https://drive.google.com/drive/folde...6d?usp=sharing

Muchas gracias, Juan Manuel.

[J M Fahey]

Cool.
Read the user manual:
*

Controls > 3 Echo Repeat: rotate Echo Repeat control for desired repeat sounds

Of course, it may be malfunctioning, in which case you must check return path/wires/potentiometer to find where signal is lost.

Here I marked the repeat path:



even if you do not have the exact model, that´s the way it works, sending the delayed signal backwards to be delayed and repeated again.

It´s basically a 70´s Japanese cassette tape recorder, with an endless cartridge, and I bet you can kludge a similar echo chamber out of an old cassette tape recorder almost unmodified, with the caveat that you must invert the cassette every 45 minutes .... tops ... not that bad.
Time to search those dusty cardboard boxes in the attic

[pretolocus]

I've already changed the potentiometer and nothing happened, so now I'll try changing the wires and the resistors. Wish me luck.
Thank you very much for the drawing!

[nickb]

You did mention that the single echo you hear was very low in volume. Could it be that the repeats are happening but very very faint? If that is the case the problem could be on the record head drive OR the playback head side of things.

[pretolocus]

I think that both heads are working well. Seems more that could be some problem on the connections of the playback head... I don't know.

[olddawg]

Start with the basics. Clean the heads and tape path with alcohol. Use a wooden Qtip. Break it in half and rub the head surfaces with it. You can’t always see the residue. Make sure the heads are not trenched. Demagnetize everything. Use a NEW tape or reload the old cartridge with new tape. Make sure that hasn’t already been done before and the tape is backwards. If that doesn’t help... you probably need an Oscope to check the oscillator and the signal path.

[pretolocus]

Thank you.
I did all of that except demagnetize and the Oscope. Will try.

[52 Bill]

Have to agree with nickb above. If the basic first recording is weak there will be very little regenerated echoes.

Of the ones that I have repaired, the tape cartridge was the usual place to solve low recording problems. The biggest problem is usually the pads that press the tape against the heads.

But olddawg makes a good point about loading the tape into the cartridge backwards so that the magnetic material side is away from the heads. Make sure that the dull side is facing out.

[pretolocus]

My friends!! Solved!!
It seems that when I changed the side of the tape I mistake and put it wrong again, so now I tried again and it works fine.
Thank you very much!
The moral of this: if only repeats once, that means that the tape isn't as should.
Cheers!

[Leo_Gnardo]

But olddawg makes a good point about loading the tape into the cartridge backwards so that the magnetic material side is away from the heads. Make sure that the dull side is facing out.

Which turned out to be the problem. DOH!

Never used to have this with the Binson Echowreck...

[pretolocus]

You are right man, if I were rich I wouldn't have half the troubles that I have.