dod 585 delay troubles

[9 volts]

Hey there, I'm trying to repair a dod 585 delay. The trouble is that the delay is very distorted and loud. I've play with the bias trims but had no luck. I read a early letter from Mark Hammer that decided s similar situation in a flanger, and mentioned hat the trouble may be with the ne570 compandor chip. I've got my audio probe out and have noticed that the only pin that doesn't have a distorted signal is pin 11 which is the one of the inputs. Does this seem like the problem? Is there any other tests I could do? Thanks

[heyniceguy]

yeah man. ive had to replace companders before. but what  you've described is right on. if you get a clean input into a chip, and a nasty crappy output on the same chip, then by golly, that chip's got some 'splainin' to do.

in basic terms, the compander is a gain controller. it's job is to take a variable voltage input signal and either compress (decrease gain) or expand (increase gain) the input so the output stays pretty consistent volume-wise. that companded signal is fed into the finicky delay chip so you get consistent level delays.

so yeah. replace that chip. www.smallbearelec.com

[9 volts]

Changed the compandor but didn't fix the problem. I notice that the sound is ok when leaving 14/15 pin on ne570 then after the 4.7 uf capacitor becomes distorted. Could this be faulty? Or would this be normal....Once again thanks

[Barcode80]

i would think the cap is faulty. those yellow caps have a fairly limited shelf life sometimes IIRC, and the 585 is at least 25 years old.

[9 volts]

Thanks before I change some capacitors I thought I'd do the voltage list. (there is alot of caps so I'm trying to pin point the area)
TL022
1)  4.15   2)  4.16   3)  4.16   4)  0.0
5)  3.96   6)  4.17   7)  4.17     8.37

TL022
1)  1.62   2)  1.8   3)  1.8   4)  0.0
5)  5.64   6)  5.86   7)  5.85     8.40

NE570
1)  1.62   2) 1.8   3)  1.8   4)  0.0
5)  1.8   6) 4.66   7)  4.66     1.8
9)  1.8   10) 5.8   11) 1.8   12) 1.8
13) 8.4   14) 1.8   15) 1.8   16) 1.0

4007UBE
1) 00   2) 8.38   3) 8.38   4) .02
5) .01   6) .01   7) .01
  8.38   9) 3.9   10) 7.62   11).01
12)  7.57   13) 8.38   14) 8.38

MN3005
1) 8.20   2)3.82   6) 4.66   7)4.66
.01   9) 3.88   13) 3.62   14) .5

MN3101
1)7.61   2) 3.88   3) .01   4) 3.89
5) 7.18   6) .68   7) 4.14    .52

2n5089
E 0.0   B .59   C 5.0
E 0.0   B .38   C 8.3
E 5.87   B 6.28   C 8.4
E 0.0   B 0.0   C 1.56    *This one connects to 4007.........does this one seem shakey?

2N4124
E .24   B .76   C 4.14

J111
D 8.35      G 8.56      S 8.3
D 4.15      G 4.16      S .08

Once again any insight appreciated!

[Dan N]

Why are those voltages so low? You are using 2 batteries, right?

[9 volts]

yeah but my batteries are wired parallel. this is a 585a. Eg two negs to to input jack two red to somewhere else....I thought that was weird but assumed it was 18 on the power pack 9 on the battery.

[9 volts]

Ok, I've changed the battery connections so now I'm running 18 volts. This has got the voltages up (i'll redo my voltage list). In the meantime I've noticed that there is leakage on my blend pot feeding back into the delay...... So  the blend is influencing the repeat effect causing crazy feed back at a low level and when I turn it up the feedback loop reduces.........I may start changing those capacitors......could the problem be anything else? 
ps starting to lose hair over this one

[9 volts]

Replaced the caps and we're rockin! Great sounding delay

[Dan N]

Congradulations!

[s_roee]

my 585A has 3 problems:
1. The delayed pitch is very unstable, and can add unexpected jumps that sound like UFOs...
2. The delayed signal is a little distorted.
3. lately, the delay adds a very high-pitch noise (something around 20K I guess..). it is not too strong, but it is noticable.

any Ideas?