Hey guys I need some help and input. I have a early 70s "answering machine", a Phone-Mate pm-400s and I wanna make an echo/tape delay out of it. The problem is Ive never done anything like this. Ive built hundreds of pedals but never something like this so I have no idea where to start. Ive attached some pictures and a youtube video that someone made a few years back that gives a good over all look at it. I bought it a few yrs ago with this intent in mind and I'm hoping we can get this thing running instead of throwing it out. Any help is greatly appreciated. Thanks guys.
https://youtu.be/YPBi95-5YXI
(https://i.postimg.cc/XpF28msV/20220302-125249.jpg) (https://postimg.cc/XpF28msV)
(https://i.postimg.cc/s1GKjbdp/20220302-125335.jpg) (https://postimg.cc/s1GKjbdp)
(https://i.postimg.cc/VJWKyMyp/20220302-125341.jpg) (https://postimg.cc/VJWKyMyp)
(https://i.postimg.cc/ZB2cPx3B/20220302-125530.jpg) (https://postimg.cc/ZB2cPx3B)
(https://i.postimg.cc/KRXfRQxC/20220302-125559.jpg) (https://postimg.cc/KRXfRQxC)
(https://i.postimg.cc/zHhkxHSd/20220302-125559-HDR.jpg) (https://postimg.cc/zHhkxHSd)
(https://i.postimg.cc/NyGpQMBM/20220302-125928.jpg) (https://postimg.cc/NyGpQMBM)
(https://i.postimg.cc/62ycGm7x/20220302-125932.jpg) (https://postimg.cc/62ycGm7x)
(https://i.postimg.cc/NyNbFcjx/20220302-125941.jpg) (https://postimg.cc/NyNbFcjx)
(https://i.postimg.cc/2V4wvv5y/20220302-125948.jpg) (https://postimg.cc/2V4wvv5y)
I remember being amazed at the intro for "Rockford Files" as a small kid, that a phone could answer itself, ha ha. Watching - if you can pull this off, it'll be a great project!
It would appear you have one thing working to your advantage, in that the unit appears to use 1/4" tape, rather than the thin 1/8" tape used in cassettes, and the even thinner tape used in micro-cassettes found in answering machines during the '80s and '90s.
What I'm less sure of is what's doing with the tape mechanism. The lower tape appears to be one continuous loop -presumably for the outgoing message - in contrast to the more familiar feed/take-up reel arrangement for the incoming messages.
If you wanted to make the unit a tape echo, you would need to have a separate record and playback head (preferably more than one if you're aiming for Echorec/Echoplex territory) I can only see one head in the two-reel side of the unit. It is not uncommon for a single head to be used for both record AND playback, but of course you can't play back what you're recording while you're recording it, so a single all-purpose head kind of botches the mission.
I applaud your effort, but I suspect this machine is not going to be the vehicle for what you want to do.