Archive of the former Yahoo!Groups mailing list: Vintage Simmons Drums (UK) Users Group

I have replied individually to those who have had problems with the cartridges but I thought a group response was in order.

Firstly, if someone has CF displayed almost immediately after selecting HI or LO kit this is indicative of the SDS not being able to put the cart into "write" mode. Those who have got the cart to work can check this by simply putting the cart switch to "safe". If there is a delay of around 2 seconds before the CF, this indicates that data was written to the cart but when the SDS verified the data (part of the save process) it did not match what is in the SDS's main memory.

Before the carts were sent I used 2 methods to check their operation;
1) I built a small unit that simply loaded a data pattern into the cart then verified
it matched. It would indicate a pass or fail via 2 LED's. This process was repeated 5 times.
2) If that passed I then checked each cart with 2 SDS7's through a number of DUMP-LOAD cycles. If this passed they were deemed "fit for use"

I was not able to check with my SDS6 as it's in bits getting an overhaul so I am pleased to hear at least one user has had success with their SDS6.=)

When I first did testing, the carts would work on one of the SDS7's but were giving problems on the second unit. In my case, I took the lid off the SDS and simply pulled the CPU, cartridge ribbon etc and "re-seated" them in their respective sockets. I can't guarantee that this will work for you.

As the SDS range is close around 30(+) yrs old, some are bound to be having functionality problems. The signal path for all the address lines, data lines, chip select signals etc MUST be present, and functional. They MUST be of low electrical resistance and free of "electrical noise". So with this in mind some things to check are;
1) the rear socket has no bend pins, there are no foreign bodies (bits of conductive foil etc) in amongst the pins and that the pins are clean of any dark oxidization or tobacco smoke residue (yep this can build up to a nice thick insulating layer over a long period of time)
2) the ribbon cable from the backplane to the expansion board has good conductivity on every line. The plugs are well seated in there sockets and the socket pins are clean and free of oxide. It is also wise to check that ALL the solder connections from the sockets to their respective PCB's are all good (no dry joints, no cracked failed joints or PCB tracks)
3) The CPU board is seated properly in it's backplane socket. It MUST be at 90 degrees to the backplane, NO other angle (not even a few degrees) as this will not allow for good electrical contact of the "fingers" inside the backplane socket. All the connections on the CPU board must be in good condition and free of oxide. The solder connections on the CPU card must be electrically good, no dry joints, cracked solder joints etc.

It is also possible your RAM card may not be the best, but working on this is sure to erase any patch data you have stored so if you want to check it out, be prepared for the long haul of re-entering patch data. I have noticed the ribbon from the backplane to the cart socket is quite short and runs in amongst the AC power wires and the AC transformer. This is NOT good practice, mixing digital data and AC electrical noise. I would suggest re routing the ribbon (difficult because it is short) well clear of the AC section. I intend to make a new cable for mine which is an inch or so longer. THe cable and plugs are readily available and any good techhead or electronics guy will have no problems making a new one. I will probably go a step further and buy the more expensive shielded ribbon, earthing one end of the shield to the SDS ground.
This will ensure no electrical noise can be induced onto the cart lines.

It is also possible that some older SDS units have an older OS eprom that contained a bug or did not support the cart properly. This is something I can't confirm, but it may be a factor. I have an eprom reader/burner so it would be possible to read my the eprom from my working units and burn a replacement for someone to try. (time consuming so not something I would want to do very often). Some users may have noticed even the process of D.U.M.P - HI is sometimes a bit "flakey". On one of my units, I sometimes get halfway through the process then the display goes back to the start and I have to do it a few times to get it to work. This is probably due to dodgy switch contacts but I haven't yet looked into it. (just and example of how the age of these things can cause issues)

It is wise to try the cart on a second unit. Out of 40+ made, I had 5 fail during the testing process (haven't checked them out as to why yet but probably a PCB defect or component fault). Of those that are in the wild (those tested and sent), I have reports of 4 problems (3 users) so it is difficult to diagnose why. All other reports I have received indicate they worked well.

I am more than happy to refund those who are finding they can't get theirs to work, but I would suggest you get your SDS fully checked out first. I have enough PCB's etc to make a few more original clones but do not intend at this stage to do another batch. Any future new carts would be an improvement on the original with USB, larger capacity etc

I will do my best to ensure that everybody is happy..=)

Richard