Last night, I got the boards for the memory expansion module for the Prophet 3000. I built a couple up and they work! All four banks check out in both the Voice chip and DMA chip tests. One of my P3000’s (the rev B, with the I-627B already installed) is having issues with bank 4 when tested with the DMA chip. The Rev B unit had the RAS signals switched around so that you could get two banks of memory without needing the upgrade board, the downside being all of the track cutting and jumpers. The rev A unit (which most P3000’s are) is working flawlessly with both the I-627B daughterboard and the memory expansion board. It works fine with the 3.0B OS, not so much with the WCP1.6A OS. So, there’s a bit of a catch-22: If you upgrade to the I-627B and 8 Meg, you may not be able to use SCSI, but if you stay with the I-627A, you can’t expand the memory. Once more testing has been done, I’ll contact Wine Country and see if they can modify the OS to work with both SCSI and the I-627B. The existing SCSI implementation is pretty limited, as far as I can gather: You can’t actually format the drive on the P3000, it has to be pre-formatted on a Mac with OS 7.x (who even has one of those these days??). The actual problem with WCP1.6A is with loading some floppy disks, so maybe SCSI will work – once I can get a properly formatted drive.

Pictures to follow….

I just got the boards back from PCBcart for the I-627 transition board. I’ve built one prototype, and will test it this weekend.

The website has moved to a new host, so there may be some interruptions over the next few days as I sort things out.

UPDATE: Things appear to be working OK now.

UPDATE 2: The adapter works perfectly!! However, I still have to test it with the expanded RAM module which is still a few weeks away. Currently I only have 1 bank of memory installed.

Over the last few months I’ve had several DSS-1 boards sent to me for repairs following unsuccessful modifications. So, I’ve decided to change my policy regarding upgrades. Going forward, I will only support installation by an authorized service center. I only have time to either build the boards, or do repairs and installation, but not both. And it ends up being just as expensive to have the boards repaired as it is to send them to a service center in the first place.

Contact me for a list of people that I’ve authorized to perform the upgrade.

I’ve completed designs for the Prophet 3000 I-627 rev B memory controller adapter in collaboration with Martin Day in the UK (thanks Martin!). Martin successfully upgraded his 2MB Prophet 3000 to a 4MB unit.

A bit of history: The first revision of the Prophet 3000 (most of which were shipped to Europe) had a first generation custom voice controller chip, the I-627. This chip takes the sound data from RAM and generates 8 voices worth of sample playback. The first generation chip (in a PGA style package) has problems using multiple banks of memory, which is why most Prophet 3000’s only have 2MB. After Yamaha bought Sequential in 1988, they redesigned the I-627 and changed the package to PLCC. The main PCB of the P3000 was redesigned for the PLCC I-627, and these units can be expanded to 4MB.

The corrected I-627 is available from Wine Country Productions; however until now there was no solution to retrofit the first generation Prophet 3000’s. Additionally, the schematics were updated for the new I-627 pinout on one page only, and the rest of the schematics refer to the old PGA I-627. Martin identified the pinouts for the PGA I-627 and cross checked the newer PLCC I-627. He constructed an adapter board for the newer I-627, but unknown to him, there are several errors in the schematics which prevented proper operation. Luckily I have one of each revision of Prophet 3000, and was able to find the errors. It appears as though there was a documenting error with the newly revised I-627. Two power pins were swapped (which Sequential solved by physically removing the PLCC socket contacts for those pins), and the RAM bank select signals were out of order (which they solved by cutting the PCB and using wire jumpers). With the newer units, they reassigned the banks so that banks 0 and 1 were on the PCB and banks 2 and 3 were on the memory expansion connector. I don’t know if Sequential ever made a memory expansion board, but if they did they are very rare.

I’ve completed a design for a memory expansion board which will require the I-627 rev B adapter board for older units. If all goes as planned, this set of boards can be installed without any soldering or modification of the main PCB. Stay tuned!

Well, we finally made it through 2012, the Mayan apocalypse didn’t quite happen and we haven’t fallen off the financial cliff (yet).

The interest in the SP-2 SCSI kit is increasing, and demand for the DSS-1 upgrade kit is still strong. I have just ordered PCB’s for another 50 kits, and I have several DI-10 and SP-2 kits in stock. I also have a few SP-3 for the ASR-10 left, although they will probably get installed in the ASR-10’s that I have here.

I have had some requests for other upgrades, especially the DSM-1. I’m currently looking into doing an upgrade for the DSM-1, and hopefully I’ll have something to announce in the next few months.

The DSS-1 mod kits are sold out until early next year. Thanks to everyone that bought one!

My current focus is on the SP-2 SCSI interface for the EPS-16. Garth at Rubber Chicken Systems has kindly referred his customers to me, as nobody is making the SP-2 anymore. I’m starting off with 30 units, and will build more if demand is strong.

I am also redesigning the CEM5530 board. It’s going to be a 4 layer board and be a bit smaller and have a cleaner layout. There is also someone else who has designed a CEM5530 replacement, and it looks very nice.

Getting a couple of DSS-1’s ready for customers this weekend. I now have 2 left, and I’m reducing the price to $450 since they have some cosmetic issues. I also have some other items for sale, check out the Gear for Sale page.

I’m finding it so easy to update the site now that I’ve revised several sections. I’ve added information on almost every section, and added a couple of new ones, for the EPS-16 and EIII. I’m also going to try and find a way to have direct download links for the DSS-1 files and other hard-to-find files. I have a bunch of EPROM images that might be useful…


I finally have the site moved over to a new server and am using WordPress. All thanks to my brother Paul, who did a superb job on this site and his own, Airborne Sound.

I have the following boards available now:

DSS-1 upgrade kit $250.00
DSS-1 board modification $100.00
DSS-1 full upgrade installation (includes board modification) $150.00

ASR-10 SCSI board $249.00

ASR-10 digital I/O board $199.00

EPS-16 SCSI board $149.00

Prices do not include shipping. For small orders, shipping is $15 in the lower 48 United States, $35 for the rest of the world.

I’ve officially sent out an email letting all interested parties know that the kit is available again. This time, I’m going to focus on just building and testing the boards and let the installation be done by the end user or a local service center. The new style boards require more end-user work, but it’s mostly removing IC’s and installing sockets.

We’re pretty much done with software development for now; both mine and Jim’s schedules will only allow for bug fixes or minor tweaks. That may change in the future. SCSI support is pretty much gone. The new board has locations for the SCSI components but I won’t be installing them unless by special request.

Next, I have to work on a revised service manual to go with the new CPU board. The text is almost done, just need to take some pictures of the process.

Hopefully there are a few people left who haven’t lost interest and moved over to soft-synths…