Vintage Synth Repair

hi folks, im wondering if anyone might provide some insight into repairing the reverb circuit in my 2600.

it was VERY noisy, so per mark vail's instructions in the "vintage synthesizers" book, i rewired the tank with shielded wire, and swapped the 6 LM301's on the reverb board for TLE2071's. these, at least as i can tell, are pinout equivalent(i removed the freq comp caps across pins 1-8 on all 6, and socketed them).

but now, the reverb SEND signal is not reaching the tank. if i push up the reverb faders, and physically tap the tank, i hear sound and can tell that the pickup portion is working, but the send from the VCA output is not. 

any leads? thanks for the help.

in typical space cadet fashion, i had seated one of the opamps backwards. DUH. she is purring like a kitten now! sounds fantastic.


all opamps should have the little notchy thing. just the dot is too easy to mess up. 


--- In vintagesynthrepair@yahoogroups.com, "r_j_d_2.phila" <r_j_d_2.phila@...> wrote:

>
> hi folks, im wondering if anyone might provide some insight into repairing the reverb circuit in my 2600.
> 
> it was VERY noisy, so per mark vail's instructions in the "vintage synthesizers" book, i rewired the tank with shielded wire, and swapped the 6 LM301's on the reverb board for TLE2071's. these, at least as i can tell, are pinout equivalent(i removed the freq comp caps across pins 1-8 on all 6, and socketed them).
> 
> but now, the reverb SEND signal is not reaching the tank. if i push up the reverb faders, and physically tap the tank, i hear sound and can tell that the pickup portion is working, but the send from the VCA output is not. 
> 
> any leads? thanks for the help.
>

Hi r j d,

;

Oh how nice of you owning an ARP2600, I envy you!!

Maybe you would consider sending few photos of the beast and maybe also some sounds or perhaps a song attachment if you have some spare time. I'm just curious.. knowing that I would never probably own one.

Thanks and best of luck with your synth. in shining armour!

Regards,

eons

in typical space cadet fashion, i had seated one of the opamps backwards. DUH. she is purring like a kitten now! sounds fantastic.

all opamps should have the little notchy thing. just the dot is too easy to mess up.

--- In vintagesynthrepair@yahoogroups.com, "r_j_d_2.phila" ...> wrote:
>
> hi folks, im wondering if anyone might provide some insight into repairing the reverb circuit in my 2600.
>
> it was VERY noisy, so per mark vail's instructions in the "vintage synthesizers" book, i rewired the tank with shielded wire, and swapped the 6 LM301's on the reverb board for TLE2071's. these, at least as i can tell, are pinout equivalent(i removed the freq comp caps across pins 1-8 on all 6, and socketed them).
>
> but now, the reverb SEND signal is not reaching the tank. if i push up the reverb faders, and physically tap the tank, i hear sound and can tell that the pickup portion is working, but the send from the VCA output is not.
>
> any leads? thanks for the help.
>