[sdiy] ARP 2500 schematic question for 1027 Cocked Sequential Controller

[Travis Thatcher]

Thanks, yeah last night while looking more closely at the schematic I
kinda figured that out. Sorry for the multiple posts too - i didn't
get any confirmations for a day or so and I tried again.  Guess just a
list hiccup.

I'm going to replace a few of the transistors in the typical driver
circuits for the 8th step as well as in steps 1 and 2. The latter work
as far as cv goes but the lamps don't light and they don't appear to
be blown.

Next up, if successful is trying to figure out why both oscs in a dual
osciallator won't respond to cv of any kind.  They hi/low freq
switches work but the oscillators are stuck. I'm thinking its the
summing op-amp which I'm going to try to replace today. Weird that
those amps would be bad on both boards though. I traced the cv to the
card contacts and that path is fine.

http://www.guitarfool.com/ARP2500/1023.html

Thanks for the help!!

On Wed, Oct 1, 2014 at 11:06 AM,  <gordonjcp at gjcp.net> wrote:
> On Fri, Sep 26, 2014 at 04:06:55PM -0400, Travis Thatcher wrote:
>> Hi all,
>>
>> Trying to troubleshoot why step 8 of an Arp 2500 1027 Clocked
>> Sequential Controller does not produce any voltage on any of the 3
>> outputs, nor does the gate out work. I'm wondering if anyone knows
>> what chip/circuit the TD1-10 is and also what PL-#s are?
>>
>> http://www.guitarfool.com/ARP2500/images/1027_sch.jpg
>>
>> Thanks!
>
> Just a guess, but is "TD" the "Typical Driver" shown at the top right? "PL" looks like it might be "Panel Lamp", a small incandescent bulb.
>
> --
> Gordonjcp MM0YEQ
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



-- 
http://www.travisthatcher.com
http://www.soundcloud.com/thevoiceofsaturn
http://voiceofsaturn.blogspot.com