Hi, I know that symptom but any tech hasn't see it yet so I can't help you.
In Btw the SDS9 has been the most reliable Simmons I had of all till now. Wth the V.
& a breakdown appeared when I set a Zero force socket Insertion for the Eproms on both of my units... would you beleive ?
I'm sure it's not a really bad one but well it needs investigation.
Nothing about PSU nor recapping has been done on them yet (but it will).
We seem to be at the same place with a different way to acces to it... :)
An old british tech told me to start by removing all the Eproms & unsoldered circuits, & checking if all th contacts are well clean... But I think you already did it.
THE AMPLIFIED HISS ON THE SDS9 HEADPHONES is a sort of... "normal" ... Well at least I heard that on all of them I had in my hands... even close to new.
So It's not normal at all but it was in the package ^^ ...Magic of Simmons ;)
The firts to resolve the Issue tells the other . It might be you actually as mine won't be seen before a few weeks.
Good luck !
P.
----- Mail d'origine -----
De: simmonssds7fan <
ptmetcalf@...>
À: Simmons Drums <
Simmons_Drums@yahoogroups.com>
Envoyé: Wed, 12 Jun 2013 20:07:06 +0200 (CEST)
Objet: [Simmons Drums] More issues with my SDS-9
First off, I'd like to thank those that have helped me along with repairing this, but I'm currently at a standstill.
What's been replaced so far: all the caps and IC's in the input mux and mux/demux circuits. This hlped the issue with the low tom circuit with the constant triggering.
The unit also had a random triggering issue with all but the bass channels, almost like the autorun function was stuck, but instead of sequentially triggering, it would randomly trigger channels until all were triggered at the same time constantly, causing basically a constsant buzz noise. Someone mentioned that it may have been an issue with the logic circuit. So, I decided to replace the IC's in the logic/computer circuit as they were pretty reasonably priced. Only the main processor chip: P8031AH, and the PPI chip P8255, were not available as new. I did find New Old Stock chips though, that did appear to be new and unused.
Now the issue: when I turn the unit on, the 4 led's for the kit bank (A,B,C,D) BREIFLY come on and go out, but the "mode" led and the 7 segment led never come on. The unit does generate an amplified hiss through the headphone output jack, like normal amp noise waiting for something to happen is the best way I can describe it. When I try to trigger the unit with the pads, I get nothing. Also, the select buttons do not seem to do anything either. I've checked and rechecked the board to make sure no circuits were damaged from the IC replacements and have found no damage. The unit seems to act like it's waiting for data, but not seeing it. I have tried a few different OS EPROMs, including the original one which did work before and there is no change. I also tried the original processor chip (it is in a socket, s no big deal to change) and it does the same thing with either processor chip. I'd like to note that I did NOT replace the 6116 RAM chip for fear
of data loss, so that is original.
What am I missing here? Is there an initialization sequence I need to do that I am unaware of? Is it possible that the PPI chip (P8255A) that I got is defective? The best way I can describe what the unit is doing is like this: it is like an old DOS based PC, whereas you have the blinking cursor on the screen waiting for you to tell the computer what to do. Does this make sense to anyone?
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