Ace tone tape echo machine question- Echos for just a moment. Any ideas?

[MarkJapan]

Hi good people! new member from Wisconsin now living in Japan. I love the site! I have an old Ace tone tape echo machine. It gives really strong echos for about 10 seconds just after I turn it on, then the echos fade to a real low distorted sound. New tape, clean heads, proper tape tension it must be something electrical. I replaced all the caps on the board that controls the echos and was hoping that would do it but it acts the same way. two other boards and the power board inside. any suggestions?

[MarkJapan]

This is the beast in question

[MarkJapan]

The mic volume is not effected. The mic or instrument still sounds strong but the echos diminish to a real muffled sound. If turn it off and back on I get strong, clear, loud, echos again but only for a few seconds.

[Enzo]

Scope it, is the bias oscillator maybe failing to oscillate?

[MarkJapan]

No scope,
but thanks for the reply

[The Dude]

This goes back a few years and I could be wrong or have the wrong machine. I vaguely remember circuit boards that plug into connectors and having problems with those connections. If it's the delay I'm thinking of, clean the contacts on the circuit boards and connectors. Re-tension if necessary. If you can post a gut shot, I can verify and/or better explain- or, it will confirm that my memory is shot.

[Mick Bailey]

I see this problem occasionally with Copicat machines where one or more transistors in the oscillator section fails when they warm up. A targeted blast of freeze spray momentarily restores full operation and quickly pinpoints where the fault lies. Of course, any component can suffer from thermal breakdown and the Mullard Lockfit transistors fitted to Copicats can be particularly problematic nowadays. Still, my thought is that you have a problem with the bias signal dropping. In the absence of a scope you may be able to see this with your DMM set to AC volts and monitoring what happens to the oscillator output as the machine warms up.

[oc disorder]

No schematic I'm sorry to say but a little info + pics ESTECHO

http://estecho.com/2016/12/ace-tone-...essional-echo/

The original link I found here https://web.archive.org/web/20100607...one_EC-10.html

and there they mention a Bazza sorry... Barry an Australian and unfortunately Australia is a big place and I haven't been able to find him !

Originally these links apparently linked to his modifications but don't link to them now.
I'll put them here in case it jogs someones memory.
http://charliehall.proboards.com/ind...ead=2234&page= 1
http://charliehall.proboards.com/ind...ead=3394&page= 1

[MarkJapan]

Thanks a lot for the time and suggestions gentlemen. I will be going back at it soon and let you know what I find out.